Note: Descriptions are shown in the official language in which they were submitted.
637~
BACKGROUND OF THE INVENTION
This invention relates to an optical device or
article. More particularly, it relates to such an article
or device including a molecularly oriented highly birefringent
polymeric material.
Materials having a birefringent character have been
variously applied ill connection with -the construction of
filter and other optical devices. Frequently, a birefringent
element utilized in an opt eel filter or other device will
comprise a plate made from a monocrystalline form of biro-
fringent material. Single crystals are expensive materials
and are not readily formed to the desired shape or conformation
required in particular applications. The size to which crystals
can be grown represents an additional limitation on the utile-
lion of such materials in optical devices.
Optical devices including a birefringent material in
the form of a polymeric layer, such as may be formed by the
unidirectional stretching of a suitable polymeric material,
have also been described. Thus, light-polarizing devices -;
utilizing a polymeric birefringent layer have been described
in US. Patent 3,213,753 (issued October 26, 1965 to H.G.Rogers).
Optical devices including polymeric birefringent materials have
so been set forth, for example, in US. Patent 3,506,333
issued April 14, 1970 to E. H. Land) and in US. Patent
3,610,729 (issued October 15, 1971 to Erg Rogers). Frequently,
the efficiency of an optical filter, polarizing or other
optical device including a birefringent element or layer will
pod upon the realization of large net differences in
aye en between a birefrin~ent malarial and adjacent
or contiguous layers. In general, such net differences will
¢
be maximized where a birefringent material is highly biro-
fringent. Correspondingly, large net differences in refractive
indices of contiguous layers will be unattainable where biro-
fringent polymeric materials otherwise suited to application
in an optical device tend to exhibit either low or only
marginal birefringent character. Accordingly, optical devices
including polymeric layers or elements exhibiting a highly
birefringent character will be of particular interest for
optical applications and enhanced efficiency.
O SUMMARY OF THE INVENTION
The present invention provides an optical device or
article Nash includes a molecularly oriented and optically
uniaxial highly birefringent polymer. The polymer comprises
repeating molecular units exhibiting high electron density
substantially cylindrically distributed about the long axis of
the polymer and the repeating units thereof. It has been
found that the birefringent character of a polymer is
importantly related to the molecular configuration or structure
of the repeating units of the polymer and to the distribution
O of electron density about the long axis of the polymer and
the repeating units thereof. Thus, it has been found that the
provision, in a transparent polymeric material comprising a
plurality of repeating units in chain-extended relationship,
of a substantially cylindrical distribution of electron density
about the long axis of the polymer permits the realization of
high birefringence and the simulation in a polymeric material
of optical properties of a uniaxial crystal. I-
The present invention, thus, provides an optical
device or article including a transparent molecularly
3 oriented highly birefringent polymer, said highly birefringent
polymer comprising repeating molecular units exhibiting high
--2--
electron density substantially cylindrically distributed about
the long axes of the polymer and the repeating units thereof,
said highly birefringent polymer being optically uniaxial
exhibiting only two indices of refraction. It has been found
that birefringence of a polymeric material useful in
articles or devices of the present invention exhibit biro-
fringence in relation to the molecular configuration of the
repeating molecular units and the cylindrical or ellipsoidal
electron density distribution about the axes of the polymer and
o the recurring units thereof, said birefringence being in
relation to said molecular configuration and said electron
density distribution according to a dimensionless geometric
index G represented by the relationship
G - 0.222 x E x D
wherein E is a dimensionless eccentricity factor defined by
the relationship
1 + e
where en is the longitudinal eccentricity of the polarizability
of the repeating molecular unit and eta is the transverse
O eccentricity of the electron pursuability of the repeating
molecular unit, L is the length of the repeating molecular unit
along the Cain axis thereof and D is the mean diameter of the
repeating molecular unit.
A preferred article of the present invention is a
multi layer light-transmitting device including at least one
additional transparent layer hazing an index of refraction
substantially matching one index of refraction of said layer of
transparent molecularly oriented highly birefringent polymeric
material and comprising isotropic or birefringent material; said
) at least one additional transparent layer, when a layer of biro-
fringent material, having one index of refraction thereof
I
--I-- t.. _ ., .
substantially different from one index of refraction of said
layer of transparent molecularly oriented highly bixefringent
polymeric material and having a molecular orientation substantially
perpendicular to the molecular orientation of said molecularly
oriented highly birefringent polymeric material.
THE DRAWINGS
Fig. 1 is a geometric representation of molecular
dimensions of a repeat unit of a polymeric material.
Fig. 2 is a cross-sectional view along the line
1-1 of Fig. 2.
Fig. 3 is a vectorial representation of bond and
group polarizabilities of a repeat unit of a polymeric material.
Figs. pa and 4b show, respectively, ellipsoidal and
circular cross-sectional distribution of electron density
about the long axis of a recurring unit of a polymeric material.
Fig. 5. is a diagrammatic fragmentary edge view of a
light-transmitting device of the present invention illustrating
the transmission of light rays there through.
Fig. 6 is a diagrammatic side view of an automotive
vehicle headlamp which includes a light-polarizing filter of
the invention.
Fig. 7 is a diagrammatic fragmentary edge view of
another embodiment of the present invention showing incident
light thereon being partly transmitted and partly reflected
as separate linearly polarized components vibrating in ortho-
gonad directions.
Fig. 8 is a diagrammatic side view of an optical
beam-splitter device including a bire~ringent polymeric material.
DETAILED DESCRIPTION OF THE INVENTION
o As indicated herein before, the present invention
provides an optical device including a transparent, molecularly
oriented and highly birefringent polymeric material. The biro-
fringent polymeric material of the devices of the invention
comprises repeat molecular units which exhiklt high electron
density substantially cylindrically distributed about the long
axes of the polymer and the repeat units thereof. The polymeric
material, comprised of repeating units of molecular structure
such as to provide a substantially cylindrical distribution of
electron density about the long axis or backbone of the polymer,
exhibits optical anistropy ox birefringence in accordance with
the relationship
G c 0~222 ( 1 -I eta ) D
where G represents the geometric index of a repeating unit;
en is the longitudinal eccentricity of the electron polarize-
ability of the repeating molecular unit; eta is the transverse
eccentricity; L is the length of the repeating unit along the
main axis thereof; and D is the mean diameter of the repeating
molecular unit. The contribution to birefringence of the
molecular structure of a repeating, chain-extending unit and
of electron density distribution will be better understood by
reference to the drawings hereof.
In Fig. 1 is shown a geometrical representation of
a repeating chain-extending molecule-- unit of a polymeric
material. Each repeating unit may thus be visualized as a
repeating rod-like segment of finite length L and of a
generally cylindrical configuration. Birefringence has been
found to be importantly related to the molecular structure of
the repeating units of the polymer in accordance with the
relationship of geometric index G, set forth herein before. A
highly birefringent polymeric material useful in the optical
I devices hereof will thus comprise a plurality of molecular units
n chain-extended relationship, each unit having a length L,
shown in Fig. 1. The long axis X of each repeating unit forms,
in the chain-extended polymer, the long axis or backbone. Each
axis in Pig. 1 forms a right angle with respect to any other
axis The mean diameter D, sex forth in the geometric index G,
is determined for each repeating unit by the expression
Y + Z
D = 2 . In Fig. 2 is shown along line 1-1 of Fig. 1, a
cross-sectional view. The shown Y and Z axes are at right angles
to one another, the X axis comprising the axis of the cylinder
extending in a direction normal to the plane of the paper.
In addition to a rigid rod-like geometry in a
polymeric material as the result of an end-to-end combination
of repeating units, the electron density distributed around
the long axis of the polymer, variously treated as a cylindrical
or ellipsoidal distribution, is believed to comprise a major
contributing factor to optical an isotropy or birefringence.
sigh electron density substantially cylindrically distributed
around the long axis of a polymer is exhibited, for example, in
a polymer of coaxially-bonded repeating units comprising non-
coplanar, particularly orthogonal, biphenyl groups. An ortho-
gonad relationship between adjacent phenylene rings can be nearly
attained by the placement of substituents with large steno
effects on at least one ortho-position of each rink, relative
to the inter-ring bond. In Fig. 3 is shown a vectorial reps-
sensation of bond and group polarizabilities of a repeating
I unit of a polymer. It will be appreciated that electron density
distribution about axis X will be variously treated as a
cylindrical or ellipsoidal distribution depending upon the
relative magnitudes Okay the Y and Z vectors. In Fig. pa is
shown an ellipsoidal cross-section along the axis of Fig. 3
where the magnitude of the shown Y vector is greater than that
of the Z vector. Ideally, Y and Z vectors would be equal and
the resulting circular cross-sectional distribution along the
X axis is shown in Fig. 4b.
By a combination of lonc3itudinal eccentricity (eland
transverse eccentricity (eta), based upon bond and group
polaxizabilities, and the length and mean diameter of a
repeating unit, a geometric index, G, related lo optical
an isotropy or birefringence, can be represented as follows:
G = 0.2~2(-1 +- eta D
wherein elm eta L and D have the monks herein before ascribed.
Longitudinal eccentricity en may be represented according to
the following relationship
~X2 _ (~)
Transverse eccentricity eta may be represented by
the relationship
r--2 2
Lo Z
eta y
wherein the magnitude of vector Y is the larger of the Y and
Z vectors. Ideally, transverse eccentricity eta will equal
zero and longitudinal eccentricity en will equal one, in which
case, eccentricity factor, E, will equal the theoretical maximum
ox two.
Geometric index G can be calculated for a variety of
repeating units of a polymer material by resort to mean
diameter and length values and longitudinal and transverse
eccentricity values calculated from experimentally determined
. . ,
dihedral angles. It will be appreciated that the magnitude of
values of length, mean diameter, longitudinal eccentricity and
transverse eccentricity will mate~ialltyinf7uence the value ox
geometric index G. Thus, it will be appreciated that a repeating
unit having, for example, a length of about twice that of a
--7--
repeating unit having a different molecular structure end con-
fiqura~ion will have a geometric index of about twice that of
such different repeating unit. Accordingly, in making compare-
sons of geometric indices and magnitude thereof in relation to
structural differences between comparative molecular repeating
units, such differences in length should he borne in mind.
In general, experimentally determined values of
birefringence for polymeric materials comprised of repeating
units as aforedescribed will correlate directionally with values
of geometric index, G, of the repeating units. Thus, in general,
recurring units having higher geometric index values provide
polymers exhibiting higher birefringence. Polymeric materials
comprised of repeating units having a geometric index value, G,
of about OHS or higher exhibit high birefringence and can be
utilized in the optical devices of the present invention. It
will be preferred, however, that polymeric materials comprising
repeating units having geometric index values of one or higher
be utilized herein. Especially preferred herein are polymers
comprising repeating units of geometric index value of 1.2 or
higher. Experimentally determined birefringence values for polyp
metric materials have been found to correlate with calculated
geometric indices. For example, a geometric index of 1.20 was
calculated or the recurring structural unit of the following
polymer:
H O H H
Theoretical maximum birefringence (I Max) was obtained ox
plotting the orientation function for the polymer (calculated
from infrared dichroism) against the measured birefringence of
the polymer and extrapolating to 100~ orientation. A Max
value of 1.20 was obtained. In like manner, a correlation of
geometric index 5 of 1.18 and ma of 0.98 was obtained in
connection with the following polymer comprising the shown
recurring uric
L N
CF3 n
A number of polymeric materials comprising recurring
units having a geometric index as herein before refined of about
0.5 or higher can be suitably employed in oriented form as a
birefringent polymeric material in an optical device
of the present invention. Rigid rod-like polymeric materials
comprised of recurring or repeating diva lent units having inter-
bonded p-phenylene moieties of non-coplanar molecular configure-
Zion are especially suited herein and are generally characterized
by geometric index values of one ox greater an by high biro-
ingenue. Exemplary of recurring units of high geometric index
and high birefringence are certain polyamide materials
including recurring units comprised, for example, of inter-
bonded aromatic rings where the aromatic rings are in twisted
relation to one another, it where the aromatic rings are in
a non-coplanar molecular configuration with respect to each
other or, preferably, in mutually orthogonal planes. It has been
found that the presence of substituent moieties on inter bonded
aromatic radicals, of type and position such as to effect a non-
coplanar molecular configuration with respect to the inter bonded
aromatic radicals, provides a recurring unit having a high
geometric index. The condition of non-coplanarity among aromatic
rings in a recurring unit, or presence in such units of rings
in "twisted" configuration relative to one another has been
found to be importantly related to high birefringence in the
rigid rod-like oriented polymers resulting grow the end-to-end
joining of such recurring units.
Among polyamide materials suited to application as
highly birefringent layers in the devices of the invention are
polyamides comprising repeating units of the formula
JO O R
to - A C - N - BUN
wherein each of A and B is a diva lent radical, except that B
can additionally represent a single bond; R and Al are each
hydrogen, alkyd (e.g., methyl, ethyl), aureole (e.g., phenol,
naphth~yl), alkaryl (e.g., toll), aralkyl (ego bouncily); c is
zero or one; and wherein, when c is one, at least one of A and
B is a diva lent radical selected from the group consisting of:
(1) a diva lent substituted biphenyl radical
We Or
where U is a substituent other than hydrogen, each
W is hydrogen or a substituent other than hydrogen,
p is an integer from 1 to 3, each X is hydrogen or
a substituent other than hydrogen and r is an
integer from 1 to 4, said U, We and Or substitution
being sufficient to provide said radical with a
non-cop1anar molecular configuration; and
(it a diva lent substituted stilbene radical
--10--
I
where each of Y and 7, is hydrogen or a substituent
other than hydrogen and each t is an integer
from 1 to 4, with the proviso that when each said
Z is hydrogen, at least one said Y substituent
is a substituent other than hydrogen positioned
on the corresponding nucleus o'er with respect
Z
to the -C= moiety of said radical, said and Ye
substitution being sufficient to provide said
radical with a non-coplanar molecular configuration;
and wherein, when c is zero, A is a diva lent radical selected
from the group consisting of radicals (1) and (~) as herein-
before defined.
As used herein, substitution sufficient to provide a
radical with a non-coplanar molecular configuration refers to
substitution of type and position effective to confer to the
inter bonded aromatic radical thereof a non-coplanar molecular
configuration such that the value of the geometric-index, as
herein before defined, is about 0.5 or higher. Preferably, the
nature of such substitution will be sufficient to provide a G
0 value of 1.0 or higher, and most preferably, 1.2 or higher.
As described herein before, birefringent polyamides
useful in devices of the present invention include those come
prosing recurring units of the formula
I
t C - A C - N - No ho
wherein c is zero or one and wherein A (when c is zero)
or at least one of A and B (when c is one) comprises a
substituted diva lent biphenyl radical or a subset-
tuned diva lent stilbene radical. Thus, when c is zero,divalent radical A comprises a substituted biphenylene radical
having a non-coplanar molecular configuration or a substituted
... ... . . .
diva Len stilbene radical of non coplanar molecular configuration.
Similarly, when c is the integer one, one or both of diva lent
radicals A and B comprises such substituted biphenylene or
substituted stilbene radicals. It is preferred from the stand-
S point of ease of preparation that each of R and Al be hydrogen,
although each of R and Al can be alkyd, axle, alkaryl or aralkyl.
From inspection of the general formula set forth as
descriptive of recurring units of the polyamides of Formula I,
it will be appreciated that polyamides comprising the following
recurring units are contemplated when c is one:
-E Al
C - A - C - N - B - N Formula II
In such recurring units, at least one of divinity radicals
A and B will comprise a substituted biphenylene or substituted
... . ; _,_
stilbene radical of non coplanar secular configuration
conforming to the formulae
; Formula III
We Or
or
C-C formula IV
.. . . .. .. . . ...... .. . . .
Where only one of said A and B radicals is a substituted
biphenylene ox substituted stilbene radical conforming to
the radicals represented by the structures of Formulas III
and IV, toe remaining A or B radical can comprise any of a
art of delineate radicals so long as the birefringent
properties of the polyamide material are not effectively
us negated. In general, where only one of the A and B radicals
conforms to the structures represented by Formulas III and IV,
-12-
the remaining A or B radical will desirably be a delineate
radical which does not confer transverse eccentricity to the
recurring unit. Similarly, where one of radicals A or B is
a radical which confers transverse eccentricity to the
recurring unit, the other of radical A or B will desirably
be a radical which confers high longitudinal eccentricity
such that the recurring unit of the polymer exhibits a high
geometric index. Suitable diva lent radicals include for
example, unsubstituted biphenylene or s~ilbene radicals;
phenylene; trans-vinylene; or ethynylene. Also suitable are
polyunsaturated diva lent radicals conforming to the formula
Elm
c = CJ
where n is an integer of at least two (e.g., two or three) and
each of D and E is hydrogen or alkyd (e.g., methyl) and inkwell-
size of such polyunsaturated diva lent radicals as transitoriness-
1~1 }l
1,4-butadienylene, i.e., -C-C-C=C- ; and 1,4-dimethyl-trans-
H H
SHEA H
trans-1,4-butadienylene, i.e., -C - C - C = C- . It will be
SHEA
appreciated that compounds containing amino groups directly
attached to carbon atoms having linear unsaturate radicals are
not stable and that, accordingly, the aforesaid vinylene,
ethynylene and butadienylene radicals cannot serve as B radicals
in the recurring units represented by the structure of Formula II.
In general, from the standpoint of maximized biro-
fringent properties, it will be preferred that each of radicals
A and B comprise a diva lent radical exhibiting a non-coplanar
molecular configuration and conforming to the structures of
Formulas III or IV. It will be appreciated, however, that the
-13-
I
particular nature of such A and B radicals may affect the
ability to readily orient the polyamide material, as by extrusion,
stretching or the like. Accordingly, where the ability of a
polyamide material to be oriented is effectively reduced by the
presence in the polyamide of each of radicals A and B of non-
coplanar molecular configuration and conforming to the structures
of Formulas III or IV, it will be preferred that only one of
such radicals A and B of the polyamide material conform to the
structure of Formulas III or IV.
In the case of radicals A and/or B of the recurring
type represented by Formula ILL, U will comprise a substituent
other than hydrogen; W will be either hydrogen or a substituent
other than hydrogen; and p will be an integer ox from 1 to 3.
In the case of such radicals, X will be hydrogen or a subset-
tent other than hydrogen and r will be an integer of from
. 1 to 4. It will be appreciated from the nature of U, I, p,
X and r, as set forth, that at least one aromatic nucleus of
the biphenylene radical represented by Formula III will be
substituted by a moiety other than hydrogen and that such
O substituent, U, will be positioned in an ortho relationship
to the bridging carbon atoms of the biphenylene nuclei.
Preferably, each aromatic nucleus of the biphenylene radical
of Formula III will contain a substituent other than hydrogen
positioned in an ortho relationship to the bridging carbon
'5 atoms of the biphenylene radical of Formula IT and in this
case, the diva lent radical will haze the following formula
. Formula V
Jo
wherein each of and X comprises a substitutent other than
hydrogen.
The nature and positioning of substituents U, and
X of the biphenylene radical of Formula III can vary widely,
consistent with the provision of a biphenylene radical having
a non-coplanar molecular configuration. While applicants do
not wish to be bound by precise theory or mechanism in
explanation of the highly birefringent character observed in
oriented polymers comprising recurring units of high geometric
index, it is believed that the non-coplanar character conferred
or promoted by the presence in a polymer of such recurring units
provides a distribution of high electron density cylindrically
about the long axis of the polymer. This distribution is
believed to be importantly related to unusually high birefringence
observed in such polymers.
The nature of substance, U, We and Or should be
such as to provide the biphenylene radical of formula III with
a non-coplanar molecular configuration referred to herein before.
Such configuration will in part be determined by the positioning
and size of non-hydrogen substituents on the aromatic nuclei
of the biphenylene radical and upon the number of such
subsfituents on such aromatic nuclei. For example, where the
bi~,lenylene radical contains a single non-hydrogen substituent,
i.e., substltuent U, the nature and, in particular the size of
such U substituent, should be such as to provide the desired
non-coplanar molecular configuration. Suitable U substituents
herein include halogen (e.g., flyer, sheller, broom, idea);
vitro; alkyd (e.g., methyl, ethyl); alkoxy ego., methoxy);
substituted-alkyl (e.g., trifluoromethyl or hydroxymethyl);
cyan; hydroxy; thioalkyl (e.g., thiomethyl); car boxy;
sulfonic acid esters; sulinic acid esters; car boxy-
I
aside; sulfonamide; amino; and carbonyl. Substituent X can
comprise hydrogen or any of the substituents set forth in
connection with substituent U. Preferably, at least one X sub-
stituent will comprise a substituent other than hydrogen. Each
substituent W can comprise hydrogen or a substituent other than
hydrogen as set forth in connection with substituents U and X.
Normally, W will be hydrogen and p will be the integer 3.
Preferred polyamides herein are the polyamides come
prosing recurring units having the biphenylene radical of
lo Forr.lula V, ire.,
U
o Formula V
wherein each of U and X is a substituent other than hydrogen.
The presence of such non-hydrogen substituents on each of the
aromatic nuclei of the radical promotes a condition of non-
coplanarity. Examples of such preferred substituents, which may
be the same or different, include halo, vitro, alkoxy and
substituted-alkyl (e.g., trifluoromethyl). While the presence
of such non-hydrogen substituents is preferred from the
standpoint of promoting non-coplanarity, it will be appreciated
from the nature of substituents W and X set forth in connection
with Formula III herein before, that each X and W can be hydrogen
and that, accordingly, substituent U will in such instance
desirably comprise a bulky substituent such as will provide
steno hindrance to a condition of coplanarity.
In the polyamides of the present invention which
comprise recurring units represented by the following formula
O C' R Roll
Formula
_ -C A - C - N - B - N I-
either or both of radicals A and B can comprise the substituted
stilbene radical set forth herein before as Formula IV, i.e.,
-16-
y Ye
I Formula IV
~C~C
In such stilbene radicals, the nature of each Y and Z will be
such as to provide the radical with a non-coplanar molecular
configuration. Preferably, non-coplanarity will be provided by
the presence of a single non-hydrogen substituent Z. Whole each
Z is hydrogen, non-coplanarity can be provided by the positioning
of a non hydrogen Y substituent on at least one aromatic nucleus
of the radical in an ortho relationship to the -C= moiety of the
radical. Suitable non-hydrogen Y and Z substituents include, for
example, any of those set forth in connection with radicals U,
W and X defined herein before.
Examples of preferred stilbene-type radicals included
within the class represented by Formula IV include the following:
Y H
C- 1 Formula VI
where at least ogle of the Y substituents is other than hydrogen,
preferably, halo or alkoxy; and
H
C - C Formula VII
where Z is a substituent other than hydrogen, preferably halo.
Inclusive of polyamides of the present invention
represented by the structure of Formula II ore those having
recurring units represented by the following structures wherein,
unless otherwise specified, U, W, p, X, r, Y and t have the
meanings set forth herein before:
¦ - C N - Jo N ; PormulavlI
We Or We r
~17-
pi
t 30 I c I I Formula It
We Or
to con I Formula X
O H O H V H
_ CHIC = C~C - N No _; Formula XI
I
'' We Or ,
8 U H
tic = I CON ONE Jo FormulaXIII
o 'X Z Z y O H Y Z Z Y H
= C CON C = 1{~>11 Formula XIV
I - C C - C = C - C - N I)_ N}; Fun via XV
_ . . .. . .. ..
-
O Z H O H U H
C C = C C - N No Allah
X
where Z and X are other than hydrogen; and
Of U O H U Al 1
. I N J formula XVII
X X
where each X is other than hydrogen.
From inspection of the general formula set forth
as descriptive of recurring UJlitS of the polyamides,
i.e., recurring units of the formula
I - A Formula I
it will be appreciated that, when c is zero, the recurring
units will be represented by the following formula:
I
to - A - N Formula XVIII
In such recurring units, radical A will comprise a diva lent
radical having a non-coplanar molecular configuration and
conforming to the structures of Formulize and IV set
forth herein before, i.e.,
U .,
Formula III
We Or
or
C=C Formula IV
-19-
where U, W, p, X, x, Y, t and Z have the same meanings.
Inclusive of polyamides represented by the structure
of formula XVIII are those having recurring units represented
by the following structures wherein U, We p, X, r, Y and t,
unless otherwise indicated, have the meanings set forth
herein before:
C + ; ormolu XIX
C W : Formula XX
where X is other than hydrogen;
lo t I C = C I ; Formul
a XXI
O Z H H
_ I C = I N - , Formula
where Z is other than hydrogen
While the polyamides described herein
consist essentially of recurring units represented by the
.5 structures of Formulas Rand XVIII, i.e., recurring units
of the formulas
r 11 8 1 Irk I Toll
t I t
a combination of such recurring units, the polyamides can
-20-
.
also comprise recurring units not conforming to the described
structures of Formulas IIand XVlII. Examples of recurring
units which do not conform to such descriptions and which
can be present in such polyamides in proportions which do not
negate the high birefringence of the polymeric material include,
for example, recurring units having the formulas
O o
If 11
-C - G - C- , Formula XXIII
R R
-N - G - N- , or Formula XXIV
R
C - G - N- Formula XXV
wherein G is a diva lent radical such as 1,4-phenylene;
4,4'-biphenylene; vinylene; trans,trans-1,4-butadienylene;
4,4'-stilbene; ethynylene; 1,5-naphthalene; 1,4-dimethyl-
transrtrans-l~4-butadienylene; 2,4'-trans-vinylenephenylene;
trans,t~-4,4'-bicyelohexylene; 2,S,7-bicyclooctatriene-1,4-,
i.e., I< ; or
Jo ,
Other diva lent radicals can, however, serve as radical G
provided that such radicals do not adversely and materially
reduce the birefringence of the polyamide material. It will
be appreciated that G cannot represent an aliphatie unsaturated
moiety where a carbon atom thereof having such unsaturation is
to be bonded to an amino group.
The substituted polyamides utilized in devices ox
the present invention can be prepared by resort to polyamide
synthesis routes involving the polymerization of suitable acid
halide and amine monomers in an organic solvent which may
-21-
contain a solubilizing agent Suckle as lithium chloride or
chain-terminatillg agent where desired. Polyamides of the type
represented by the structure of Formula I can be prepared, for
example, by toe reaction of a dicarboxylic acid halide of the
O 0
R R
formula Hal-C~A-C-Hal with a Damon of the formula H-N-B-N-H,
where Hal represents halogen, such as sheller or broom and A
and B have the meanings herein before set forth, except that
B cannot represent an aliphatic unsaturated moiety. The
reaction can be conducted in an organic solvent such as N-
methyl pyrrolidone (NIP), ~etramethylurea (MU) of a mixture
thereof, and preferably, in the presence of a salt such as
lithium chloride to assist in the solubilization of reactant
monomers and maintenance of a fluid reaction mixture. The
preparation of a polyamide of the proselyte invention can be
illustrated by reference to the preparation of pull'-
dibromo-4,4'-biphenylene)-trans-t~-bromo-p,p'stilbbone
dicarboxamide, a preferred polyamide herein, in accordance
with the following reaction scheme:
C1- C C-C--~ Cal + HEN ~12 LlCl
By
o By H By H
I C No N- n
Polyamides containing recurring units having the
.. rod I 1
structure represented by Formula XIII, i.e., t C - A - N
can be prepared, for example, by the polymerization of a
p-amino-aroyl halide monomer in the form of a halide,
-22-
I
arylsulfonate, alkylsulfonate, acid sulfonate, sulfate or
other salt. This polymerization can be illustrated by
reference to the preparation of poly(2,2'-dibromo-4,4'-
biphenylene)carboxamide in accordance with the following
reaction scheme showing the polymerization of the hydra-
chloride salt of 2,2'-dibromo-4~amino-4'-chlorocarbonyl-
biphenyl:
Of Ho C Of 3 NO f Hal
By By n
Substituted polyamides useful in optical devices of
the present invention can be prepared by polymerization of
correspondingly substituted monomers in a suitable organic no-
action solvent. Such solvents include aside and urea solvents
including N-methyl-pyrrolidone and N,N,N'N'-tetramethylurea.
Other suitable reaction solvent materials include N-methyl-
piperidone 2; N,N~dimethylpropionamide; N-methylcaprolactam;
N,N-dimethylacetamide; hexamethylphosphoramide; and NUN
dimethylethylene urea. The polymerization can be conducted by
dissolving the monomer or monomers to be polymerized in the
reaction solvent and allowing the exothermic polymerization
reaction Jo occur usually with the aid of ox vernal cooling. In
general, the polymerization will be conducted initially at a
temperature of from about -20C to about 15C, and preferably,
in the range of from about -5C to about 5C. Thereafter,
usually within about one half hour to one hour, the reaction
will be heated with formation of a thickened polymeric mass of
gel-like consistency. In general, the polymerization reaction
will be conducted over a period of from about 1 to 24 hours,
preferably about 3 to 18 hours.
-23-
_ _ . . .
While the monomer or monomers to be polymerized can
be dissolved in a suitable aside or urea solvent and allowed
to react with formation of the desired polymeric Material, a
preferred reaction sequence where a Metro of ccpolymerizable
monomers is utilized involves the preparation of a solution
of a first monomer in the aside or urea solvent and the
addition thereto of a second or other monomer or a solution
thereof in a suitable organic solvent thrower, such as twitter-
hydrofuran. External cooling of the resulting reaction mixture
provides the desired polyamide material if. high molecular
weight and minimizes the production of undesired side reactions
or by-products.
The polyamide materials prepared as described can
be recovered by combining the polymerization reaction mixture
with a non-solvent for the polymer and separating the polymer,
as by filtration. This can be effectively accomplished by
blending the polymerization mixture with water and filtering
the solid polyamide material. The polyamide can be washed
with an organic solvent such as acetone or ether and dried,
for example, in a vacuum oven.
Polyamide materials as described herein before and
methods for their preparation a-e described in greater detail
in United States Patent 4,384,107.
the transparent highly birefringent materials
useful in the devices of the present invention have been set
forth by reference to certain polyamides, represented by the
structures of Formulas II and XVIII, it will be appreciated
that transparent highly bir~fringent polymeric materials of
other polyamide types, or of types or classes other than
-24-
,.,, I,
polyamides, can likewise be utilized herein where the repeating
units of such polymers have a substantially cylindrical duster
button of electron density about the long axis or the polymer.
Particularly useful herein are transparent polyamide
materials comprising recurring units corresponding to Formula I
hereof wherein c is zero or one, each of A and B is a diva lent
radical, except that B can additional represent a single bond,
and at least one of A and 3 is a s-~bstituted-quaterphenylene
radical having the formula
LO
1`1p Or W
wherein U, W, X, p and r have the meanings set worth herein and
the U, We and Or substitution is sufficient to provide the
radical with a non-coplanar molecular configuration.
The above substituted-quaterphenylene polyamides can
be prepared, for example, by reaction of a suitably substituted
quaterphenylene Damon and a dicarbo~ylic acid or halide. These
polymers and their preparation are described in greater detail
and are claimed in the Canadian patent application of ROY. Gaul
Diana and P.S. Kalyanaraman, (Serial Jo. 397,277) filed of even
O date herewith.
Transparent polymeric materials from classes other than
polyamides and which can be utilized herein include, for example,
polymers having thiazole, imidazole, oxazole and/or ester
linkages. For example, polymeric materials comprising the follow-
in thiazole-containing recurring units, where U, Wry X, and r
have the meanings herein before ascribed, can be utilized herein:
i 3 Us
-25-
- -
Such polymeric materials can be prepared by reaction of a
dicarboxylic acid compound of the formula
ICKY Ox C-OH
We Or
with an ami~o-thiol of the formula
2 ~y,~~y,SH
s 101
HO NH2
in a suitable organic solvent with recovery of the desired
polymeric material.
, Polymers comprising the following imidazole-
containing repeating units can also be employed herein, where
U, W, X, p and r have the meanings herein before described.
WOW
p r H
These polymers can be prepared, for example, by reaction of a
dicarboxylic acid compound of the formula
o U o
OKAY C-OH
We Or
, . . ... . .
with 1,2,4,5-tetramino-hen~ene.
Polymers containing recurring units having an oxazole
moiety can be suitably prepared by reaction of a dicarboxylic
acid compound as aforedescribed with, for example, 1,4-dihydroxy-
2,5-diamino-ben2ene, with formation of a polymer containing the
following recurring units where U, W, X, p and r have the
meaning set forth hexeinb~fore.
-26-
I,
I)
' N O J
We.. Or
Polyester materials kennels be suitably employed
herein. Exemplary of such polyesters are those having recurring
units of the formula
I I
We Or We Or
wherein each U, W, X, p and r has the meaning set forth
herein before.
Other polymers that can be utilized in optical
devices of the present invention are polymers comprising
JO recurring units of the formula
r
r Mu-C-Az-C
where Mu is a diva lent radical having the formula
--Cluck - .
D' I' .
where each of D, D', E and E' is hydrogen, alkyd or
.5 substituted-alkyl; and A is a diva lent radical having the
formula R 1'
-N-W-N-
where each of R and R' is hydrogen, alkyd, aureole, alkaryl or
aralkyl and W is a single bond, alkaline or alkenylene; or
I A is a diva lent radical having the formula
-27-
yo-yo
-N N-
where each of Y and Y' represent the atoms necessary to
complete with the nitrogen atoms to which they are bonded
a piperazine or substituted-piperazine radical.
These polymers can be conveniently prepared by
reaction of a dunk acid chlorite such as mucononic acid
chloride or dimethylmuconic acid chloride with hydrazine
or a Damon such as piperazine, 2-methylpiperazine or
2,5-dimethylpiperazine. Suitable polymers of this type and
methods for their preparation are described in United States
patent 4,393,196.
The polymeric materials utilized in the devices of
the present invention can be variously formed or shaped into
films, sheets, coatings, layers, fibrils, fibers or the like.
For example, a solution of a substituted polyamide as described
herein before, in a solvent material such as N,~-dimethyl-
acetamide, optionally containing lithium chloride solubilizing
agent, can be readily cast onto a suitable support material
for the formation of a polymeric film or layer of the polyamide
material. The polymeric film can be utilized for the product
lion of a birefringent polymeric film or sheet material which
can be utilized in an optical device of the invention. Thus,
I a polymeric film or sheet material can be subjected to
stretching so as to introduce molecular orientation and pro-
vise a film material having a highly .~irefrir.~ent character.
I
., j.
Known shaping or forming methods can be utilized for
the orientation of polymeric materials suited to application
in devices of the present invention. Preferably, this will
he accomplished by unidirectional stretching of a polymeric
film, by extrusion of the polymer into a sheet, layer or
other stretched form, or by the combined effects of extrusion
and stretching. In their oriented state, the polymers utilized
herein exhibit unusually high birefringence. To general,
treater birefringence will be observed in the case of polyp
metric materials exhibiting a greater degree of molecular orientation. It will be appreciated, however, as has been
pointed out herein before, that the particular molecular struck
lure or configuration of the polymeric material may affect
desired physical attributes of the polymer material or other-
wise impose a practical limitation upon the degree of oriental
lion that can be realized by stretching or other means. It is
a significant aspect of the present invention, however, that the
polymeric birefringent materials utilized in the devices of
the present invention, particularly for a riven degree of
. orientation, exhibit unusually high birefrin~ence. In this
connection, it is to be noted, for example, that the substituted
polyamides described herein will often exhibit higher biro-
fringence than the more highly oriented materials of different
-limerick structure. For example, an extruded film of a tub-
stituted polyamide hereof comprised of recurring units of the
formula
C = I C - N N
By
-29-
and having a degree of orientation in the range of from about
80% to 85% as determined from infrared dichroism, exhibited
a birefringence ( no of 0.865 as measured utilizing principles
of interferometry. In contrast, a polyamide fiber material and
comprised of recurring units of the formula:
o O H H
_ I C -- N N
is reported in the literature, ALA. Humus and J. Sikorsky, J.
Microscopy, 113, 15 (1978), as having a birefringence of
0.761, as measured by interferometric technique and at a degree
of orientation of about 90% to 95%.
The birefringent polymers useful in the devices
hereof will desirably simulate to the maximum practical
extent the optical properties of a uniaxial crystal.
Accordingly, the birefringent polymers will exhibit
substantially uniaxial optical behavior, i.e., only two
indices of refraction. Optical efficiency and maximum
birefringence will be realized where such substantially
uniaxial behavior is exhibited by such polymers.
The molecularly oriented birefringent polymers
utilized herein will preferably exhibit a birefringence of
at least about 0.2, and more desirably, a birefringence of
at least 0.4. Thus preferred polymers for use in the
articles hereof will exhibit substantially uniaxial optical
behavior and a birefringence of at least about 0.2 and will
be comprised or recurring units naming a geometric index
of about': 0.5 or higher.
-30-
_ = " = . = = ", .
The birefringent polymeric materials utilized in the
devices of the present invention, in addition to exhibiting
high birefringent properties, are advantageous from the stand-
point of their transparency. In contrast to polymeric materials
which become decidedly opaque as a result of stretching,
birefringent materials hereof exhibit transparency in unwarranted
end stretched forms. For example, the substituted polyamides
described herein exhibit a high transparency and a low order of
light scattering, exhibiting a ratio of amorphous to crystal-
line material of from about 10:1 to about 20:1 by weight.
These materials are, thus, suited to optical applications where
a light-transmissive, highly refractive and bireringent
material is desirably utilized. Depending upon the nature of
substituent moieties on the diva lent radicals of the recurring
units of these polyamides, colorless or nearly colorless polyp
metric films or layers can be fabricated. Inhere, for example,
nitro-substituted biphenylene radicals are present, a yellow
-31-
transparent film or giber can be fabricated. Films, coated
or other shaped forms of the substituted polyamides can be
redissolved end reshaped or prefabricated it desired. Depending
upon the nature of particular recurring units of the polyamide
materials, and particularly the nature of substituent moieties
and solvent materials, the volubility characteristics of these
substituted polyamides can be varied or controlled to suit
particular applications.
The birefringent properties of polymers utilized in
lo the devices of the present invention can ye determined by the
measurement of physical and optical parameters in accordance
with known principles of physics and optics. Thus, for example,
the birefringence L n) of a suitable birefringent polymeric
material can be determined by the measurement of optical phase
retardation (R) and film thickness (d) and calculation of
birefringence in accordance with the relationship
R
d
where represents the wavelength of light utilized for the
conduct of the measurements. Alternatively, parallel refractive
index and perpendicular refractive index of the film material
can be measured utilizing Beck line analysis or critical
angle measurement.
A preferred method for determining the birefringence
of useful polymeric materials involves the measurement of
retardation of the polymeric material by a method utilizing
principles of polarized-light microscopy and interferometry.
Such method provides desired precision and accuracy in the
measurement of the phase difference between a sample ray passing
mu through a sample of polymeric material and a reference ray
-32-
. _ ,,~
passing through a neighboring empty aria (embedding medium
or air) of the same thickness The light emitted by a low-
voltacle lamp of a microscope is linearly polarized by passage
through a polarizer and, in turn, is passed through a condenser,
a calcite plate beam splitter, a half-wave retarder plate,
the polymeric sample, a beam recombinator calcite plate, and
through an analyzer whose transmission direction is vertical
to that of the polarizer (crossed position). In the analyzer
the components vibrating in its absorption direction are ox-
tinguished, whereas the components of both rays in the trays-
mission direction are transmitted and interfere. The phase
difference between sample and reference beams, caused by the
molecular structure or configuration of the polymeric sample,
is measured with compensators. From these measurements, the
thickness and refractive index of the polymeric material can
be determined. By determining index of refraction of the
polymeric sample for both parallel and perpendicular directions,
birefringence can, by difference, be determined. A suitable
method and apparatus for determining phase retardation, index
of refraction and birefringeance for the polymeric materials
utilized herein is a pol-interference device according to
Jamin-Lebedeff described in greater detail by WAGE. Patzelt,
"Polarized-light Microscopy," Ernest Lutz GmbH, Wetzlar, West
Germany, 1974, page 92.
Preferred optical devices of the present invention are
multi layer devices which include a layer of molecularly oriented
and highly birefringent polymeric material as described
herein before, and in addition, at lest one layer of isotropic
or birefringent material. The additional layer or layers.
I whether isotropic or bire~ringent, comprises a material having
-33-
an index of refraction matching substantially one index of
refraction of the highly birefringent material. For example,
a layer of isotropic material having an index of refraction
matching substantially one index of refraction of the highly
birefringent layer can be suitably bonded to the layer of
highly birefringent polymer. A preferred device comprises a
layer of the molecularly oriented and highly birefringent
material bonded between two layers of isotropic material,
the index of refraction of each isotropic layer corset-
lo tuning substantially a match with an index of refraction
of the molecularly oriented and highly birefringent material.
Such a preferred device can be utilized for the pullers
lion of light and may be termed a "total transmission
light polarizer, i.e., one which is particularly adapted
to polarize a very large portion of incident light. Total
polarizers find application in equipment such as may be
employed fox signaling, projection and display purposes,
or the like, and in anti-glare systems for automotive
vehicles.
2Q According to another embodiment of the present
invention, a molecularly oriented and highly birefringent
material as defined herein can be suitably bonded to an addition-
at layer of birefringent material. In such an embodiment, one
index of refraction of the molecularly oriented and highly
birefrir.gent material will match substantially one index of
refraction of the additional birefringent material. Similarly,
the second index of refraction of the molecularly oriented and
highly birefringent material will be substantially a mismatch
with respect to the second index of refraction of the additional
pa by no morel Where a layer of molecularly oriented
-34-
and highly birefringent material is bonded to an additional
layer of birefringent material, the direction of oriental on
of each contiguous birefring~r.t material will be substantially
perpendicular with respect to the other.
According to another embodiment of the present
invention, a plurality of alternating isotropic and birefrin-
gent layers can be utilized for the production of a multi layer
light polarizing device, at least one of the layers of
birefringent material comprising a molecularly oriented and
highly birefringent material as defined herein. Such a
device can be utilized as a multi layer polarizer which partly
transmits and partly reflects incident light as separate
linearly polarized components vibrating in orthogonal directions.
In Fig. 5 is shown, in considerably exaggerated
dimensions an optical device of the present invention in the
form of light-polarizing sheet material 10 as it would appear
in cross-section, namely, as viewed axons a given edge.
In order of arrangement with respect to the direction of a
collimated beam 12 from a light source (not shown) the
material is composed of an isotropic, or at least functionally
isotropic layer 14 having a relatively low refractive index,
a molecularly oriented highly birefringent polymeric layer 16
and a functionally is~txopic layer 18 having a relatively
high refractive index, the layers preferably being laminated
or bonded together to form a unitary structure. It is not
essential to the proper functioning of the device that the
layers thereof be bonded together; provided, however, that
adjacent or contiguous layers enclosing an air layer are
maintained parallel to one another One refractive index of
the polymeric molecularly oriented and highly birefringent
-35-
- -
layer 16 matches substantially that of layer 14 while the other
refractive index thereof matches substantially the index of
retraction of Mayer 18. For purposes of illustration, the alone-
said refractive indices may be liken as follows: the refractive
index of layer 14 is 1.50; the two indices of layer 16 are 2.00
and 1.50; and the index of layer 18 is 2.00.
The interface between layers 14 and 16 is composed
of a plurality of lens-like or lenticular elements aye and the
interface between layers 16 and 18 is composed of a plurality
of lens-like or lenticular elements 16b. It will be noted that
Lye lenticules of one interface are offset, laterally, with
respect to those of the other. The term "lenticular", as
employed herein, may broadly be interpreted as constituting a
plurality of surface configurations, including prismatic
elements, as well as those of a strictly lens-like form. A
certain degree of latitude is possible as to the choice of
materials employed in forming the several layers. Thus, for
example, layer 14 may suitable be composed of an isotropic
plastic material such as poly~methylmeth~crylate) having a
refractive index of 1.50. Layer 16 can, accordingly, be come
posed of a transparent plastic layer which, for example, has
been rendered birefringent as by unidirectional stretching.
Suitable for this purpose is the polymeric material, pull'-
bis(trifluoromethyl)-4,4l-biphenylene]2",2"'-dimetthwacks"'-
biphenyldicarboxamide having refractive indices of 1.50 and
2.00 when thus rendered birefringent. Layer 18 can be suitably
comprised of or incorporate a transparent isotropic material
having an index of refraction approximating the higher index of
birefringent layer 16.
-36-
. .
One such material is poly(2,2'-dibromo-4,4'
biphenylene)-4,"4"'-stilbenedicarboxamide having an index of
refraction of 2.07. Alternatively, layer 18 can comprise
poly(2,2'-dibromo-4,4'-biphenylene)-~-bromo-4",4"''-stilbene-
dicarboxamide having a refractive index of 2.05.
One method of constructing the sheet material is to
form the birefringent layer 16 by a casting, or a casting and
embossing procedure, after its proper solidification, and
casting the isotropic layers 14 and 18 on the opposite lunatic-
far surfaces thereof. The birefringent layer I may be composed
of substantially any material having a birefringence adapted
to facilitate the required separation of light ray components
and having indices of refraction which bear a proper relation
to those of the contiguous layers 14 and 18. It may also be
formed by any of several different procedures. Assuming, by
way of illustration, that the birefringence of layer 16 is to
be achieved to ought its molecular orientation, a sheet or
film of properly deformable material, such as the aforementioned
material, poly[2,2'-bis(trifluoromethyl)-4,~'-biphenylene]-
2",2"' -dimethoxy-4",4" -biphenyldicarboxamide, i.e., a sheet
of a given length and predetermined thickness, can be first
extruded or cast. The sheet can then be subjected to a mechanic
eel stress in a longitudinal direction to elongate and Milwaukee-
laxly orient it, as by a stretching operation in the presence
of heat or other so toning agent, or by a cold drawing method,
or, again, by applying a mechanical stress to its surface.
The direction of stretch or other application of orienting
stress is to be taken as having been performed toward and away
from the viewer, namely, in a direction normal to the plower
of the awry; is being the case, the optic axis 20 of layer 16
constitutes a direction both in the plane of layer 16 and
normal to the plane of the paper.
Birefringent layer Lo, having acquired the desired
birefringence 25, for example, a birefringence of 1.50 and 2.00,
assuming the stated refractive indices, can then be subjected
to surface modification to form thereon the converging or
positive lenticular elements aye and the diverging but
functionally converging or positive lenticular elements 16b.
This can be suitably performed by passing the material between
embossing means such as embossing blades, wheels or the
like, the surfaces being slightly softened as by a solvent or
heat, or both, as may be necessary during their treatment
but not to such an extent as would relax the material and
alter the previously provided orientation and birefringence.
The embossing procedure is preferably performed in a direction
along that of the optic axis, to facilitate preservation of
the given orientation. Accordingly, the lenticules, as
illustrated, are generally cylindrical with their axes
extending parallel to the optic axis. As will be apparent
and explained in further detail below, the lenticules play
a major role in the predetermined separation and focusing
of the respective rays. While len~icular means of the type
described constitute one preferred configuration, they may be
so formed as to extend in other directions of the sheet or
even have a spherical shape, provided that their refractive
characteristics are properly chosen and the birefringence of
the material is suitable. Alternatively, the lenticules may
be formed by a grinding and polishing procedure or the sheet
may be stretched or otherwise treated for orienting its
-38-
molecules after the lenticules have been formed thereon.
After completion of the surfacing of the birefrinqent
'ever 16 and either prior to or after its orientation, the
isotropic layers 14 and 18 are assembled therewith or formed
- 5 thereon by any appropriate method such as by casting them in
liquid form on the preformed layer 16. Assuming that the
material of layers 14 and 18 is not of a type to cause any
disturbing double refraction of light rays when solidified
and subjected to mechanical stress, as by stretching, the
stretching and desired molecular orientation of layer 16 may
be accomplished after casting and solidifying layers 14 and
18 on it surfaces, the entire sheet 10 then being stretched
as a unit. Or, the layers 14 and 18 may be cast on layer 16
after orientation of the latter. Alternatively, and again
assuming layers 14 and 18 to be substantially incapable of
becoming birefringent when stressed, they may be preformed
so as to have the lenticular surfaces shown, superimposed in
correctly spaced relation, the birefringent layer 16 formed
there between in a fluid state and solidified, and the entire
unit then stretched. In a further modification, the layers
14 and 18 may be preformed and assembled with layer 16, in
either a bonded or non-bonded relation therewith, after the
layer 16 has been treated to acquire a proper birefringence.
It has been noted with reference to Fig. 5, that the
lenticules aye and 16b are relatively offset from left to
right, that is transversely of the sheet 10, so that the Yen-
tires of lenticules aye are optically aligned with the
longitudinal edges or intersections of lenticules 16b.
While the lenticules aye and 16b are shown as being spherical
and of similar radii ox curvature it will be understood that
-39- .
neither of these conditions is essential, per so, the choice
depending in general upon the directions in which the rays
are required -to be refracted, the extent of their travel in
said directions, and such factors as the refractive indices
and thicknesses of the layers.
The collimated beams 12, emanating, for example,
from a light source and reflector of a headlamp (not shown)
- and normally incident upon the isotropic layer 14, are
transmitted without deviation through the latter to the
converging cylindrical lenticules aye of birefringent layer 16.
At layer 16 each beam is resolved into two components, that
is an ordinary or "O" ray aye and an extraordinary or "E"
ray lob. Bearing in mind that the refractive index of
isotropic layer 14 has been given as 1.50 and the refractive
indices of birefringent layer 16 as 1.50 and 2.00 let it be
assumed that the 1.50 refractive index applies to the
components aye which, or purposes of illustration, Jill be
considered the ordinary jays vibrating substantially at
right angles to the optic axis. Inasmuch as these rays
have a refractive index which is essentially identical to that
of layer 14, which precedes layer 16 in order of their travel,
they are refracted by lenticules 16b so to converge generally
toward a theoretical focal plane, not shown. The rays aye pass
through isotropic layer 14 without deviation inasmuch as the
refractive index of 1.50 and that of layer I are substantially
identical. The components lob, which in this instance are
taken as the extraordinary rays vibrating in a plane passing
through or parallel with the optic axis and having a refractive
index ox: 2.00 identical to that of the isotropic layer 18, are
I refracted by the lenticule!3 aye because of the dissimilarity of
I
respective refractive indices. However, the diverging or
negative lenticular surface aye constitutes, in effect a con-
verging lenticular surface of isotropic layer 14, the components
i2b thereby being refracted convergently toward the aforesaid
theoretical focal plane. As described, the layer 16 is
positively birefringent inasmuch as the refractive index ox
the E ray is represented as greater than that of the O ray, but
a reverse condition is possible. The rays aye and 12b,
generated in birefringent layer 16 are plane polarized, their
vibration directions being at 90 to one another as indicated.
The rays are thence transmitted WitilOUt alteration of their
state of polarization with their vibrational planes normal
to one another.
Either the E or the O ray, or both, may be selectively
treated, as by passing them through retardation materials,
to provide their vibrations in a single azimuth as will be
described below. Even without such treatment and a non-
uniformity of vibration directions, the sheet material of
Fig. 5 has certain uses such, for example, as for illumination
purposes where it is desired to polarize the light partially
in a Yin direction, for three-dimensional viewing or for any
function wherein transmission of a large part of the incident
light is of importance but wherein completely uniform polarize-
lion throughout a given area is not essential. While the entering
rays 12 are shown us collimated at 90 to the plane of the sheet,
a slight departure from this condition, from left-to-right in
the drawing, can exist without preventing operation of the device
of Fig. 5 or of others illustrated herein and a wide deviation
therefrom may exist in a direction along the axis of the
lenticules.
Consistent with obtaining an operational refraction
or non-refraction of rays generally similar to that shown in
Fig. 5, the several layers may be formed of substantially any
materials having suitable refractive in cues, transparency
and physical or mechanical properties such as thermal
stability, flexibility or adhesion. Thus, for example,
layer 14 may be composed of any of such materials as twitter-
fluoroethylene, vinyl acetate, cellulose acetate bitterroot,
an acrylic material, glass or the like. Birefringent layer 16
can be, for example, poly[2,2'-bis(trifluoromethyl~-4,4'-
bip~.enylene~4",4"' -stilbenedicarboxamide having indices of
refraction 1.61 and aye or a layer of poly(2,2'-dlbromo-
4,4'-biphenylene~-4"/4"' -stilbenedicarboxamide having indices
of 1.77 and 2.64. Layer 18 can be a polymeric material which
has been rendered birefringent but which has its optic axis or
direction of molecular orientation at 90 to that of layer 16,
it being understood that its len~icular surface Gould match
with that of layer 16 at 16b.
In an optical device of the present invention, the
indices of refraction of the several layers can be modified
or adjusted in predetermined manner such that the proper
functional relation between the indices of refraction of the
several layers is maintained. Thus, the indices of refract
lion of the several layers may be controlled in predetermined
fashion by altering plasticizer content. For example, the
index may key lowered by the addition of plasticizer. Where
bonding substances or subgoals are employed in laminating
preformed layers, a material used for such a purpose Shelley
have an index of refraction similclr to that of one of the
-42-
. _ _ _ . _ . _ . . , .. . .. , _ . .. .. . ... . . _ . _ .
layers undergoing bonding to prevent unwanted reflection.
According to another embodiment of the present
invention there is provided a light-polarizing element
comprising a prismatic layer of molecularly oriented biro-
fringent material and an isotropic or functionally isotropic layer. Such an element can be utilized in a device such as
the headlamp of an automotive vehicle.
In Fig. 6 there is shown a headlamp 30 which
includes a specularly reflecting parabolic mirror 32, a
filament 34, a diffusely reflecting plate element 36 and a
light-polarizing sheet material 40. Light-polarizing element
40 includes a prismatic layer 42 of molecularly oriented and
highly birefringent polymer and an isotropic layer 44, the
refractive index of the isotropic layer a substantially
matching the low index of refraction of birefringent layer 42.
Thus, for example, birefringent layer 42 may have refractive
indices of 2.0~ and 1.50 and layer 44 a refractive index
of 1.50. An unpolarized collimated beam 12, upon entering
birefringent layer 42, is resolved into O and E components
aye and 12b, as previously described in connection with
the device shown in Fig. 5. The prism elements of biro-
fringent layer 42 are so formed and disposed relative to
the incident collimated beam 12 that the E ray 12b is no
floated rearwardly to the parabolic mirror 32, is reflected
to diffusely reflecting element 36, whereat it is Doppler-
Zen, is reflected to mirror 32 and thence to light-
43-
polarizing sheet material 40 as a second collimated unpolarized
beam 12d. The prism elements, may, for this purpose, appear-
privately be prisms or so-called hollow corner cubes which
have the characteristic of reflecting collimated light rays in
the direction whence they came. The O ray aye is transmitted
without deviation straight through layer 44 which matches its
refractive index. Thus procedure repeats itself, ad infinitum,
it being apparent that eventually substantially all of -the
light from source 34 is transmitted in the form of collimated
O rays having a uniform azimuth of polarization.
According to still another embodiment of the present
invention, there is provided a multi layer light-polarizing
device effective to linearly polarize a large portion of the
light incident thereon and to transit substantially all of
one polarized component of light while reflecting substantially
all of the orthogonally polarized component. Such a polarizer
is shown in Fig. 7 as polarizer 50 having alternate layers 54
and 56 of molecularly-oriented, highly-birefringent material
and of isotropic or functionally isotropic material.
The layers 54 are each composed of a molecularly
oriented birefringent materiel. For instance, the material
may comprise poly~2,2'-bis(trifluoromethyl)-4,4'-biphenylene]
2",2"' -dimethoxy-4",4"'-biphenyldicarboxamide. Other materials
can also be utilized in forming the birefringent layer and
should be selected to have as great a difference between the
two indices of refraction as possible since the number ox
layers in the polarizer can be substantially decreased when
using bi,-efringent materials having a greater difference
between their indices of refraction.
I
The isotropic layers 56 may be composed of a
number of different materiels with the requirement that its
refractive index substantially match one of the refractive
indices of the birefringent material layers on either side
thereof. Some examples of materials which are useful for
this purpose include polyacrylates, poly(2,2'-dibrGmo-4,4'-
biphenylene)4",4"' -stilhenedicarboxamide, silicon oxides or
titanium dioxides. The isotropic layers can be provided, for
example, by vacuum deposition so that their thickness can be
precisely controlled. Alternately, the isotropic layer may be
co-extruded simultaneously with the birefringent layers
interleaved there between.
As shown in Fig. 7 the optical axis 58 of each
birefringent layer lies in a plane parallel to the planar
substrate surface 60. This is accomplished, for example,
through the use of a stretch orientation operation. Layer
thickness can be suitably controlled by the extrusion
process and allowances for dimensional changes expected in
the layer thickness during the stretching step can be made.
Fig. 7 schematically shows a number of light rays 62
incident on polarizer 50 and traveling in a direction
perpendicular to the surface thereof. As an example, the
birefringent layers 54 may have a pelf of refractive indices
of no = 1.50 and no = 2.00 and the refractive index of
each isotropic layer may be taken as n = 1.50. As each
ray 62 passes through the first bir~fringent layer 54, it is
-resolved thereby into two components shown as separate rays,
. I
namely/ an extraordinary or "E" ray aye for which the biro-
fringent layer has the higher index no = 2 7 00 and an
ordinary ray or "O" ray 62b for which the birefringent layer
has, for example, the lower index JO = 1.50 , the rays
traveling in a similar direction and with their vibration
azimuths relatively orthogonally disposed as depicted in
the drawing. As shown in jig. 7, a portion 62c of the "E"
rays aye is reflected at the first interface 64 -cached, it
being recalled that the refractive index of an isotropic
lyres given at n = 1.50 The reflection is due to the
refractive index discontinuity at the interface between the
layers 54 and 56 which exists for the "E" polarization but
not the "O" polarization. For purposes of illustration the
reflected light rays 62c are shown as being reflected at a
slight angle while in actuality they are reflected straight
back it the direction of rays aye. Thereafter each inter- ¦
face such as 66 and 68 will reflect a further portion of
ray aye. The rays 6~b are unreflected at the interface 64
because the refractive index for "O" rays 62b in layer 54
matches that of layer 56 and in fact, these rays 62b will
pass through all layers 54 and 56 unreflected and comprise
that portion of the light incident on the polarizer that is
transmitted thereby.
In order to greatly increase the reflectivity of
the polarizer 50 each layer 54 and 56 is made to have an
optical thickness of one-quarter the length of a selected
wavelength. The optical thickness is equal to the physical
thickness multiplied by the index of refraction of the layer b
material. The wavelength selected is preferably in the
middle of the visible spectrum, for example, 550 no so that
I
_ . . .. ... .
I
the polarizer is effective over a substantial range of
visible light. This arrangemerlt utilizes optical inter-
furriness to enhance the efficiency of the polarizer. The
following discussion relates to phase changes in a light
wave, not to changes in the the polarization azimuth of
the light wave. In analyzing the optical properties of the
polarizer, it is important to remember hat light suffers a
phase change of on reflection when it goes from a medium
of low refractive index to a medium of higher refractive
index while it suffers no phase change on reflection when
it goes from a medium of high refractive index to a medium
with a lower refractive index. Thus, in Fig 7, a light
ray such as aye, as it passes through the first quarter-
wave birefringent layer 54 will suffer a phase change I
As the light ray strikes the first interface 64 part of it
is reflected back through the first birefringent layer 54
again suffering a phase change of I the total phase change
being equal of I + I If. Note that tune ray aye suffers
no phase change on reflection at interface 64 due to the
I rule as stated above. Now as the remaining portion of
ray aye strikes the second interface 66, it has traveled
through two layers suffering a phase change of I I
in one direction and I + I on reflection. The ray aye
will also suffer a phase change of r on reflection due to
the above rule and the total phase change will equal 4 I +
or 3 I. Thus, in accordance with this analysis, the
ray aye will always suffer a phase change of some multiple
of as it is reflected from each and every interface in
the multi layer polarizer. Each reflected component 62c of
ray aye and other such similar rays will reinforce one
-47-
another resulting in substantially total reflection of the
one polarized component of incident light represented by
rays aye providing the number of layers and interfaces are
sufficient. The other component 62b will pass undisturbed
through the multi layer polarizer 50 so long as the refractive
index of the isotropic layers 56 match one of the refractive
indices of the birefringent layers 54. Since substantially
none of the rays aye are transmitted, the entire amount of
light output from polarizer 50 consists of rays 62b, ail
polarized in one direction.
In Fig. 8 is shown on optical beam-splitter device of
the present invention embodying a layer of birefringent polymer.
Beam splitter 70 comprises prisms aye and 72b of isotropic
material]. such as glass joined in a Nikolai configuration with
layer 74 of molecularly oriented birefringent polymer there-
between. Elements aye and 72b can be composed of a variety of
glass or other isotropic materials and will have a per pen-
declare index of refraction greater than that of the polymer
layer 74 between such elements. For example, a unidirection-
ally stretched layer 74 of poly-[2,2'-bis(tri~luoromethyl~-
4,4'~biphenylene]-~,2'-dimethoxy-4,4'-biphenyl having a per pen-
declare index of refraction of about 1.65 and a unidirectional
stretch direction as indicated in Fig. 8 can be utilized
between isotropic glass elements aye and 72b of refractive
index I In operation, unpolarized light 76 enters element
aye and a portion thereof is reflected at the interface of
element aye and layer 74 50 as to emerge as plane-polarized
light 78. A portion of light 76 is refracted by layer 74 and
emerges from element 72b as oppositely plane polarized Lotte 80.
Light 76 is thus split into separate beams of oppositely
polarized light by beam splitter 70.
I
ilk particle cmbodilnc~ s of the prcscn~ invcn-
lion utilizing polymeric birefrinyen~ layers have bean
; described in connection wit the devices Shelley in Fig 5
to 7, other devices utilizing such polymeric bircfrillgcnt
layers can also be prepared. Examples of other devices which
can be adapted to include a polymeric all highly birefringent
layer as described herein are described, for example, in
US. Patent 3,506,333 (issued April 14, 1970 to Eland;
in U. S. Patent 3,213,753 (issued October 26, 1565 to
H. G. Rogers); in U. S. Patent 3,610,729 (issued Oc'obcr 5,
1971 to H. G. Rogers); in US. Patent 3,473,013 (issued
October 14, 1969 to H. G. Rogers); in US. Patent 3,522,984
(issued August 4, 1970 to H.G.Rogers); in US. Patent 3,522,985
; (issued August 4, 1970 to }I.G.Rogers); in Us Patent 3,528,723
(issued September 15, 1970 to H.G.Rogers); and in So Patent
3,582,424 (issued June 1, 1971 to K. Nervous). Still other
devices that can be prepared utilizing a birefringent polymer
hereof include Wallaston prisms, Russian prisms, Fuessner
prisms, Brewster polarizers, non-polarizing beam splitters,
compensators and the like.
The following non-limiting examples are illustrative
of the present invention.
-49-
x7\~lp~
This cxarnplc illustrates the preparation of posy
(2,2'-dibromo-fi t fi'-biphcnylclle)-p,p'-biphcnylene dicarboxaMidc
and the preparation therc~om of birefringent polymeric films.
A 50-r~ll. Rockwell vessel (a resin-making cattle
equipped Wltil a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying Tokyo) was heated while simultaneously
flushing the Bessel wit nitrogen. After the reaction vessel
had cooled to room temperature, 1.63 grams of an hydrous
lithium chloride and 0.5746 gram ~0.00].679 mole) of sublimed
2,2'-dibromobenzidine were added while maintaining a positive
I nitrogen pressure. The reaction vessel was fitted with a
. .
thermometer and a rubber stipple (a rubber membrane e
sealing lid capable of receiving a syringe and of sealing
lo itself upon removal of the syringe). Ten mls. of an hydrous
distilled N-methylpyrrolidone (NIP) and 15 mls. of an hydrous
distilled ~e~=~methylurea (MU) were carefully added with the
Jo
aid ox syrinxes. The resulting mixture was stirred and
warmed to 40C until all solids had dissolved. The solution
was when cooled in a heath ox ice and salt to a temperature
! of -5C. A small amount of lithium chloride precipitation
was obs~rvcd. Recrystallized p,p'-biphenylene dicarbonyl
chloride (0.4689 gram; 0.001679 mole) was quickly added by
means of a funnel to the stirred 2,2'-dibromobel-zidinc
solution. on additional five mls. of MU were added through
the funnel to the reaction mixture. The temperature of the
reaction mixture did not rise above a temperature of 7C.
After stirring for 60 minutes, the reaction mixture bran
to thicken and streaming birerringence (but not stir
opalescence) was observed.
! The ice bath was removed from the reaction vessel
Al 15 and the temperature was observed to rise to 20C in 30
minutes at which point the reaction solution became milky
l in appearance. The reaction vessel was placed in an oil
; bath (40C) and the reaction mixture was warmed for 30
minutes. The reaction mixture became clear. The temperature
of the reaction mixture rose during the warming to a maximum
temperature of 55C at which temperature the reaction Metro
was stirred for one hour. The reaction product, a 3% wt~/vol.
polymer solution (three grams of polymer per 100 mls. of reaction
solvent) was cooled to ~0C and poured into 200 mls. of ice-
water in a blender. The resulting fibrous solid was filtered and washed (in the blender) twice each with water, acetone
and ether. The product was dried in a vacuum oven at lo mm.
pressure and 90C fur 18 hours the product, obtained in
95,4~ yield, was a white fibrous polymeric material having
the following recurring structural units:
G C- N
~-51
.
The inherent viscosity of a polymer solution
(0.5 gram of the polymer ox example 1 per 100 mist of a
I solution of five yearns lithium chloride per 100 mls. of
i dimethylacetamide)was 3.54 dl./yram at 30C.
¦ 5 Molecular structure was confirmed by infrared
spectroscopy. Inspection ox the ultraviolet/visible
absorption spectrum for the polymer of Example 1 (in So
wt./vol. lithium chloride/dimethyl~cetamide showed a Max I
320(~ = 75,000).
Elemental analysis for Creole provided
the following
J I OH Brie ON I 0
Calculated: 56.97 2 92 29 16 ;.11 5 84
Fouled: 56.86 3 25 28 72 5.10 6 07 (my difference)
lo Polymeric films were prepared from the polymeric
material of Example 1 by casting (onto glass plat2s?solutions
of the polymeric material in a 5% wt./vol. solution of
lithium chlsxide and dimethylacetamide (five grams lithium
chloride per 100 mls. of dimethylacetamide). The concentration
of polymer ranged from OHS to I wt./vol., i.e., from 0~5 gram
to five grams polymer per 100 mls. of the lithium chloride/
dLmethylacetamide solution. On each instance, toe glass
plate carrying the puddle-cast polymer solution was immersed
in water (after minimal evaporation of solvent). The polymer
film was observed to gel and a transparent and colorless
unwarranted film separated prom the glass plate. The resulting
film was soaked for several hours in water to effe-:. extraction
of occluded lithium chloride and solvent, soaked i!' acetone
and dried in a vacuum oven at 90C and 15 em. pressure.
Retractive index, Mazda by inte~fe~ometry, was ii93
-52-
Jo
S~xetchcd polymeric films were prepared in the
followillg nlanller. Wa~er-swollell films (obtained by sicken the
polymer films for several hours for removal of occluded
hum chloride and solvent as aforedescribed) were cut into
strips. The strips were mounted between the judges of a mechanic
I eel unidirectional stretcher. The strips were stretched (in
air at 220C) to about 50~ elongation, to effect film oriental
lion. The resulting films were optically transparent. Biro-
fringence, measured with the aid of a quartz wedge, was 0.293.
! lo EXAMPLE
'I
This example illustrates the preparation of posy
(2,2'-dinitro-4,4'-biphenylene)-o,o'-dinitro-p,p'--biphenylene
dicarboxamide and the preparation therefrom of birefringent
polymeric films.
A 50-ml. reaction vessel pa rcsin-making kettle
equipped with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
Louisiana l-he vessel with nitrogen. Attacker the reaction vessel
had cooled to room temperature, lo grams ox an hydrous
lithium chloride and 0.47~9 swam (0.001750 mole) of recrystal-
lived 2,2'-dinitrobenzidine yellow crystals were added while
maintaining a positive nitrogen pressure. The reaction vessel
was fluted with a thermometer and a rubber stipple and 30 mls.
of an hydrous distilled N-methylpyrrolidone (NIP) and 20 mls.
of an hydrous distilled tetramethylurea MU were carefully
added with the aid of syringes. The resulting mixture was
stirred and warmed to 40C until all solids had dis~olvcd. Lowe
solution was then cooled in a bath of ice and salt Jo a
temperature of -5C. Recrystallized colorless donator-
4,4'-biphenyl dicarbonyl chloride (0.6460 tram; 0.0')l75 Jo to)
was quickly added by means of a funnel to the Seward I
dinitrobenzidine solution. An additional three mls. of No
53
wore addocl Roy ho unloyal to the reaction mixer. The
-tempcra~ure ox the reaction mlxtu~e did not rise above a
temperature ox 0C. Altar stirring for 30 monks, there was
no nuzzle change in reaction mixture viscosity.
The ice bath was removed-from the reaction vessel
and the temperature was observed to rise to 20C in 30 minutes
at which point the reaction solution was heated in stages up
to 90C over a period ox 2.5 hours.
The reaction product, a OWE wt./vol. polymer solution
(three trams ox polymer per 100 mls. of reaction solvent) was
cooled o 40C and poured into 200 also of ice-water in a
blender. The resulting gelatinous solid was filtered and
washed (in the blender) twice each with water, acetone and
ether. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The polymeric product,
obtained in 88% yield, was a dark-yellow powder having the
following recurring structural units:
-t C C No N -}_
NO 2
The inherent viscosity of a polymer solution
(0.5 grams of the polymer of Example 2 per 100 mls. of a soul-
lion of five grams lithium chlorite per 100 mls. of dim ethyl-
... .. . . . . .. , .,, . ....... . .. ..... . ......... . .
acetamide~ was 1.40 dl./gram at 30C.
Molecular structure was confirmed by infrared
spectroscopy. Inspection of the ultraviolet/visible absorption
spectrum for the polymer ox Example 2 (in I wt./vol. lithium
chloride/dimethylacetamide) showed a Max of 30? no (I - 38,400)
and an abrasion peak at 365 no = joy).
Elemental analysis for C26H14N6Olo p
following:
3C lo Jo %0
Calcul~cd: 54.7~ 2.47 1~.73 28.06
~~~~ 5~.24 2.60 13.~1 29.25 (by do furriness)
Thermogravim~tric analysis showed that onset ox
degradation of the polymer of Example 2 occurred at 360C in
nitrogen and at 300C in air. Differential scanning calorimetry
and thermal mechanical analysis of film samples showed a repro-
educible transition at about 190C.
Polymeric films were prepared from the polymeric
material of Example 2 by casting (onto glass plots solution
of the polymeric material in a pow wt./vol. solution of
hum chloride and dimethylacetamide (five Greece lithium
chloride per 100 mls. ox dime~hylacetamide). The concentra-
lion of polymer was I wt./vol., i.e., five grams polymer per
lo lo mls. ox the lithium chloride/dimethylacetamide solution.
'In each instance, the glass plate carrying the puddle-cast
polymer solution was immersed in water (after most of the
solvent had evaporated). The polymer film was Observed to Mel
and a transparent, yellow unwarranted film separated from the
glass plate. The resulting film was soaked for several hours
in water to effect extraction ox occluded lithium chloride
and solvent.
Stretched polymeric films were prepared in the
following manner. Water swollen films (obtained by soaking
the polymer films for several hours for removal of occluded
lithium chloride and solvent as aforedescribed) were cut into
strips. The strips were marled between the jaws of a
mechanical unidirectional stretches. The strips were
stretched (in boiling ethylene glycol) to about 60~ elan-
lion, to effect film orientation. The resulting polymer;
strips Whelk optically transparent Blrefrlngence, measured
Whitehall tile aid of a quartz wedge, and by index Mekong, was
0~33. 'rho calculated isotropic refractive index was l.75.
Wide-angle Ray analysis ox the birefringent films showed
crystalllnity to be less than lo by weight.
EXAMPLE 3
_
This example illustrates the preparation of posy
(2,2'-dibromo-4,4'-b~phenylene)-o,o'-dibromo-p,p'--biphenylene
dicarboxamide and the preparation therefrom of birefringent
lo polymeric films.
50~ml. reaction vcss~l (a resin-makirlg kettle
i keypad with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
; flushing the vessel with nitroscn. Afro the reaction vessel
lo had cooled to room temperature, 2.0 grams of anhydrsus
lithium chloride and 0.7828 gram (0.002289 mole) of sublimed
2,2'-dibromober~zidine were added while maintaining a positive
nitrogen pressure. The reaction vessel was fitted with a
thermometer and a rubber stipple and 20 mls. of an hydrous
distilled N-methylpyrrolidone (NIP) no 35 mls. of an hydrous
distilled tetramethylurea MU were carefully added w oh the
aid of syringes. The resulting mixture was stirred and
warmed to 40C until all solids had dissolved. The solution
was then cooled in a bath of ice and salt to a temperature
of 0C. Recrystallized 2,2'-dibromo-4,4'-biphenylene dicarbonyl
chloride (1.0000 gram; 0.002289 mole) was quickly added by
means of a funnel lo the stirred 2,2'-dibromobenzidine
solution. An additional five mls. of rrMu~ at a temperature
of 25C, were added through the funnel to the reaction mixture.
The temperature so the reaction mixture rose to 15C and wrier
-56-
dropped to 4C. Tory stirring or 15 minutes, the wreck;
Myra Jan Jo thicken and streaming birefringcnce (buy no
stir opalescence) was observed. Stirring was continued for
an additional 30 monks at 7C and the ice bath was removed
from the reaction vessel. The temperature ox the reaction
mixture nose Jo 25C (in 90 minutes) and the reaction mixture
was then slowly heated to 100C over a Tory period.
The reaction product, a 4% wt./vol. polymer solution
(four grams of polymer per 100 mls of reaction solvent) was
cooled to 40C end poured into 200 mls. of ice-water in
a blclldcr. The resulting fibrous solid was filtered and
washed (in the blender) twice each with water, acetone and
ether. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The product, obtained in
96.6~ yield, was a white fibrous polymeric material having
! the following recurring structural units:
C C-N N
By
the inherent viscosity of a polymer solution
(OWE grams Go the polymer of Example 3 per 100 mls. or a soul-
lion of five grams lithium chloride per 100 mls. of dim ethyl-
~cetamide) was 2.04 dl./gram at 30C. Molecular weight
determination based on light scattering, indicated 2.72 x 105,
and by gel permeation chromatography, a molecular weight of
5.66 x 104. Molecular structure was confirmed by infrared
spectroscopy. Inspection of the ultraviolet/visible
absorption spectrum for the polymer of Example 3 (in I
wt./vol. lithium chloride/dimethylacctamide) showed a Max
of 305 no ( , 31,900) and no absorption above 380 rum.
Y Bryan provided the
~ollowil~g:
-57~
.
I Lo if Yin JO
Calculated: 4~.23 1.'~9 45.27 3.99 ~.52
l = 4~.5~J 2.19 45.25 3D~7 4.15 by dif~crcllcc)
it Thermogravimetric analysis showed that onset of
Al 5 degradation of the polymer ox example 3 occurred at 530C in
i nitrogen. Thermal mechallic21 analysis ox film samples showed
a reproducible transition at about 120C.
Polymeric films ware prepared from the polymeric
material of Example 3 by casting (onto glass plates) solutions
of the polymeric material in a JO wt./vol. solution of
lithium chloride and dime~hylacc~amidc (five grams lithium
chloride per 100 mls. of dime~hylacetamide). The concentration
'i of polymer ranged from 0.5 Jo I wt./vol., i.e., from 0.5 gram
to 5 grams polymer per 100 mls. ox the lithium chloride/
I, 15 dime~hylacetamlde solution. In each instance, the glass
plate carrying the puddle-cast polymer solution was immersed
in water (after most ox the solvent had evaporated). The
polymer film was observed to gel and a transparent, colorless
unwarned film separated from the glass plate. The resulting
film was soaked for several hours in water to effect extract
lion of occluded lithium chloride and solvent, soaked in
acetone and dried in a vacuum oven at 90C and 15 mm. pressure.
Refractive index, measured by interferometry,was 1.84.
Stretched polymeric films were prepared in the
following manner. Water-swollen films (obtained by soaking
the polymer films for several hours for removal ox occluded
lithium chloride and solvent as aforedescribed) were cut into
strips. The strips were mounted or stretching between e
jaws ox a mechanical unidirectional stretcher. Strips were
stretched, in some instances, in air at 220C and, in other
instance sin boiling ethylene glycol. Elongation ranged from
I
60~ to 65~. Infrared dichroism indicated that the films wore
less than 65~ oriented The films were optically transparent.
Birefringence, measured tooth the aid of a quartz wedge, was
! ox 390. ~ide-angle X-ray analysis of the bir~fr_n~ent polymer
films showed them to be less thin 10~ by weight crystalline.
EXAMPLE
This example illustrates the preparation of posy
~2,2'-dichloro 5,5'-dirnethoxy-biphenylene)-o,o'-dibromo-p,p'-
biphenylene dicarboxamide and the preparation therefrom of
birc~ringcnt polymeric films.
¦ A Smalley. reaction vessel (a resir.-making kettle
equipped with a mechanical stirrer, nitrogen inlet tube and
¦ calcium chloride drying tube) was heated while simultaneously
flushing the vessel with nitrogen. After the reaction vessel
had cooled to room temperature, 1.5 grams of an hydrous
I lithium chloride and 0.6519 gram (0.002082 mole) of sublimed
__ .
I 2,2'-dichloro-5,5'-dimethoxybenzidine were added while main-
twining positive nitrogen pressure. The reaction vessel was
fitted with a thermometer and a rubber stipple and ten mls. o
an hydrous distilled N-methylpyrrolidone (NIP) and ten mls. o
an hydrous distilled tetramethylurea (MU) were carefully added
with the aid of syringes. The resulting mixture was stirred
and warmed to 40C until all solids had dissolved. The resulting
orange solution was then cooled to a bath of ice and set. to
a temperature of 0C. A small amount of lithium chloride
precipitation was observed. Recrystallized 2,2'-dibromo-~,4i-
biphenyldicarbonyl chloride ~0.9095 gram; 0.002082 mole was
quickly added by means or a funnel to the stirred 2,2'-
dichloro-5,5'-dimethoxybenzidine solution. An additional ten
mls. of MU Nat a temperature of 25C) were adder through-. one
funnel to the reaction mixture The temperature or the
-59-
,1 .. .
reaction mixture did riot rise above a ~cmpera~urc of okay.
pharaoh stirring for 30 minute.., 'Lowe ~ormatioll ox a clue oust
light-yellow, transparent mass (which exhlbi'.ed Strom
b refringence but not stir opalesc2nc^) was observed. Syrian
was continued for an additional ten minutes at 8C, the
stirring was stopped and the ice bath was removed. The tempera-
; lure of the reaction mass was observed to rise to SKYE in 15
minutes, and the gal became stiffer in consistency. Heating
was immediately commenced and an additional 20 mls. of MU
were added to facilitate dissolution of the reaction mass.
Within 60 minutes the temperature rose Jo 90C and the gel
melted to provide a homogeneous, viscous solution.. seating at
90C was continued for two hours while stirring vigorously.
The reaction product, a 2.82~ wt~/vol. light-
yellow polymer solution I a trams of polymer per 100 mls. of
reaction solvent) was cooled to 40C and the resulting gel-
; Tunis, transparent mass was added to 200 mls. of ice-water
in a blender. The resulting rubbery solid was filtered and
washed (in the blender) twice each with water, acetone and
other. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The product, obtained in
99.3~ yield, was a very pale-yellow fibrous polymeric material
having the following recurring structural units:
By OUCH
The inherent viscosity of a polymer solution (0.5 gram or the
polymer of Example 4 per 100 mls. of a solution of five ye- my
lithium chloride per 100 mls. of dimethylacetamide) was 5.75
diagram at 30C.
-60-
Molecular structure was confirmed by infrared
spectrose~lJy~ mental allalysis for C2~l118Er2C12N2O4pro-
voodooed the hollowing:
I By clue ON %0
Calculated: 49.66 2.68 23.60 10.~ 4.1~ ~.45
; Found: 49.05 2.~5 23.07 __ 4.15 __
Polymeric films were prepared from the polymeric
material of Example 4 by castillg (onto glass plates) solutions
of the polymeric material in a I wt./vol. solution of
lithium chloride and dimethylacetamide five gyms. lithium
, chloride per 100 mls. of dimethylacetamide). The concentra-
i lion of polymer was 2% wavily, i.e., two grams of polymer
per 100 mls. of the lithium chloride/dimethylacetamide solution.
In each instance, the glass plate carrying the puddle-cast
; 15 polymer solution was immersed in water (after minimal evapora-
lion of solvent. The polymer film was observed to gel and a
transparent, colorless unorier.ted film separated from the
'j glass plate. The resulting film was Swede for two days in
water to effect extraction of occluded lithium chloride and
solvent, soaked in acetone and dried in a vacuum oven at 90C
and 15 mm. pressure. Refractive index, measured by inter-
formatter was 1.87.
Stretched polymeric films were prepared in the
following manner. Watar-swollen films (obtained by soaXir.g
the polymer films for several hours for removal of occluded
lithium chloride and solvent as a~oredescribed) were cut
into strips. The strips were mounted between the jaws of a
mechanical unidirectional stretcher. The strips were
stretched (in air at 220C) to about 50~ elongation, to
I effect film orientation. The stretched films were optically
. .
----
I -61-
.
transparent. Birefringerlce, measured with the aid ox a
Ayers wedcJc, WAS O . I .
Solutions of the polymer of Example 4, in a concern-
traction ox 3 Jo I wavily., in lithium chloride-containing
solvents (cog., dimet:hylace~amide containing lithium chloride
were found to form colorless, transparent gels which could be
melted and r~solidi~icd without thermal degradation. When ho
molten solutions were poured into molds or cast into films,
solidification was rapid and the solid pieces or films were
readily removable. The resulting rubbery solids exhibited high
birefringence upon application of very slight stress. Removal
ox the stress Wow accompanied by instantaneous disappearance
ox he bire~ringent property.
EXAMPLE 5
This example illustrates the preparation of posy
~2,2'dibromo-4,4'-biphenylene)-octafluoro-p,p'-bipphenylene
dicarboxamide and the preparation therefrom ox birefringent
I polymeric films.
;, A 50-ml. reaction vessel (a resin making kettle
equipped with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
flushing the vessel with nitrogen Aster the reaction vessel
had cooled to room temperature, 1.5 grams of an hydrous
lithium chloride and 0.4571 gram (0.00}338 mole of sublimed
2,2'-dibromobenzidine were added while maintaining a positive
nitrogen pressure. The reaction vessel was fitted with a
thermometer and a rubber stipple and ten mls. of an hydrous
distilled N~methylpyrrolidone (NIP) and ten mls. of an hydrous
distilled tetramethylurea (MU) were carefully added wl~rl the
1 30 aid of syringes. The resulting mixture was stirred en.
I warmed to 40C until all solids had dissolved. The solely;
=62-
lo
was n tooled in a bath ox ice and salt to a tcmpera~urc ox
0C. A small amount ox lithium chloride precipitation was
observed. Distilled 2,2'~,3',5,5',5,6'-octafluoro-4,4'-
biphenylene dicarbonyl chloride ~0.5660 tram; 0.001338 mole)
was quickly added by means of a funnel to the stirred,
2,~'-dibromobenzidine solution. An additional ten mls. of
'MOE (a a ~m~era~urc ox 25C) were added wreck the tunnel
to the reaction mixture. The temperature of the reaction
mixture did not rise above a temperature of 2C. After
stirring or 15 minutes, the reaction mixture began to
thicken and streaming birefringence (but not stir opalescence)
was observed. Stirring was continued for an additional 30
minutes at 4C and the ice bath was removed. The temperature
of the reaction mixture was observed to rise to 25C in 40
minutes at which point the reaction solution was slightly
viscous and cloudy in appearance. The reaction mixture was
warmed gently or 90 minutes with stirring. The temperature
of the reaction mixture rose curing the warming to a maximum
temperature of 45C at which temperature the reaction solution
became homogeneous. Stirring was continued for 18 hours at 45C.
The resulting reaction product, a 3% wt./vol.
polymer solution (three grams of polymer per 100 mls. ox
reaction solvent) was cooled to 40C and poured into 200 mls.
of ice-water in a blender. The resulting fibrous solid was
filtered and washed (in the blender) twice each with water,
acetone and ether. The product was dried in a vacuum oven
at 15 mm. pressure and 90C or 18 hours. The product,
obtained in 87.6~ yield, was a white fibrous polymeric
material having the hollowing recurring structural units
C I
-63-
The inherent viscosity of a polymer solution
(owe cJr~ln ox e polymer of example 5 per 100 mls. of a
solution ox live or lithium chloride per loo mls. of
dimethylace~amidc) was l.G8 dl./gram at 30C.
Molecular structure was confirmed by infrared
spectroscopy. Inspection of the ultraviolet/visible absorb-
lion spectrum for the polymer of example 5 (in I wt./vol.
lithium chloride/dimcthylacetamide) showed a Ajax of I no
and an absorption peak at 360 no (I = 306).
El~mC~tal analysis or C26l~8Br2F8N22 provided
''t the following:
I OH Brie OF ON OWE
Calculated: 45.11 1.17 23.09 21.97 4.05 4.61
Found: 42.89 1.17 21.86 20.81 3.76 byway di~fcr~lce~
Thermogravimetric analysis showed that onset of
degradation of the polymer of Example S occurred at SKYE in
nitrogen and at 350C in air. Differential scanning calorie
metro showed a reproducible transition at about 15~C.
Polymeric films were prepared from the polymeric
material of Example 5 by casting (onto glass plates) solutions
of the polymeric material in a I wt./vol. solution of
lithium chloride and dimethylacetamide (two grays lithium
chloride per 100 mls. of dimethylacetamide)O The concentra-
lion of polymer ranged from 0.5 to 5% wt./vol., i.e., from
... . .
0.5 gram to five grams polymer per 100 mls. of the lithium
chloride/dimethylacetamide solution. In each instance, the
glass plate carrying the puddle cast polymer solution was
immersed in water (after minimal evaporation of solvent). The
polymer was observed to gel and a transparent and colorless
unwarranted film separated from the glass plate The resulting
film was soaked for several hours in water to effect extract
.
I -64-
lion ox occluded lithium chloride and solvent, soaked in
acutely end dlicd in a vacuum oven at 90C and 15 mm. pressure.
Reflective index, measured by interreromctry was i.74.
; Strc~ched polymeric films were prepared in the
following manner. ~ater-swollell films (obtained my soaking
the polymer films for several hours for removal of occluded
lithium chloride and solvent as aforcdcscribed) ware cut into
strips. The strips were mounted between the jaws of a
mechanical unidirectional stretcher. The strips were oriented
by stretching; (in air at 200C)to an elongation in the range
of 50 to 55%. The polymeric strips were optically transparent.
i Birefrin~er.ce, measured with the aid ox a quartz judge, was
0.35. Strips were also stretched in methanol at 25C to an
elongation of 55~. Measurement of birefringence for such
; 15 ; stretched films showed a birefrin~ence of 0.44.
EXAMPLE 6
This example illustrates the preparation of posy
(~,2',3,3'~,4',6,6'-octafluoro-4,4'-biphenylene)caarbohydrazide
and the preparation therefrom of birefringent polymeric films.
A 50-ml. reaction vessel (a resin-making kettle
equipped with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
flushing the vessel with nitrogen. After the reaction vessel
had cooled to room temperature, 1.15 grams of an hydrous
lithium chloride and 0.0386 gram (0.001205 mole) of distilled
hydrazine were added Chile maintaining a positive nitrogen
pressure. The reaction vessel was fitted with a thermometer
and a rubber stipple and seven mls. ox an hydrous distilled
N-methyl~yrrolidone (NIP) and 12 mls. of an hydrous distilled
tetrame~hylure~ (MU) were carefully added with the aid of
syringes. The resulting mixture was stirred until most of
-65-
7 '11 h'
A aye.
the lithium chloride had dissolved. The solution aye thin
cooled in a bath of ice and salt to a temperature of 0C. A
small amount of lithium chloride precipitation was observed.
Distilled 2,2',3,3',5,5',6,6'-octafluoro-4,~'-biphen~lenc
5 dicarbonyl chloride (0.5100 gram; 0.001205 mole) was quickly
added by means of a funnel to the stirred hydrazine solution.
An additional four mls. of MU (at a temperature of 25C)
were added through the funnel to the reaction mixture. The
temperature of the reaction mixture did not rise above a
10 temperature ox 5C. The reaction mixture did not thicken and
; stcamin~ bircfrin~Jencc was not ob~crvcd. Lithium carbonate
(0.08~0 tram; 0.0024 mole) was added to the reaction mixture,
stirring was continued for 30 minutes at 4C and the ice bath
was removed. As the temperature of the reaction mixture rose
15 to 25C during the subsequent 60 minutes, the reaction soul-
lion first became cloudy and, then, a white precipitate formed.
; Over the next 30 minutes, the reaction mixture was warmed to
40C at which time the reaction mixture became homogeneous.
The reaction temperature was raised to 70C and maintained
20 for one hour. No increase in viscosity was apparent.
The reaction product, a 1.99% wt./vol. polymer
solution (1.99 grams of polymer per 100 mls. of reaction
solvent) was cooled to 40C and poured into 200 mls. of ice-
water in a blender. The resulting powdery solid was filtered
and washed (in the blender) twice each with water, acetone
and ether. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The polymeric product,
obtained in 95.4% yield, was a white solid material having
the following recurring structural units:
-66~
F F F I'
i The inherent viscosity of a polymer solution'
(0.5 gram of the polymer of Example 6 per 100 mls. of a
solution of five grams lithium chloride per 100 mls. of
dimethylacetamide) was 1.16 dl./gram at 30C. The molecular
structure of the polymer of Example 6 was confirmed by infrared
spectroscopy.
Polymeric films were prepared from the polymeric
material of Example 6 by casting (onto glass plates) solutions
of the polymeric material in a I wt./vol. solution of
I, lithium chloride and dimethylacetamide (two grow lithium
chloride per 100 mls. of dimethylacetamide). The concentra-
lion of polymer ranged from 0.5 to I wt./vol., i.e., from
'I 0.5 gram to five grams polymer per 100 mls. of the lithium
chloride/dimethylacetamide solution. In each instance, the
grass plate carrying the puddle cast polymer solution was
immersed in water (after evaporating the solvent for one
hour). The polymer film was observed to gland a physically
weak, cloudy and colorless film separated from the glass
plate. The resulting film was soaked for several hours in
water to effect extraction of occluded lithium chloride and
solvent, soaked in acetone and dried in a vacuum oven a
90C and lo mm. pressure. The films were not of sufficient
strength to undergo stretching. Refractive index, measured
by interferometry,was 1.60.
EXAMPLE 7
-
This example illustrates the preparation of posy
(2,2'-dibromo-4,4'-biphenylene)-t~ p,p'-stilbene dicarbox-
aside and the preparation therefrom of birefringent polymeric
films.
-67~
250-ml. reaction vessel (a resin-making kettle
equipped with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
slushing the vessel with nitrOcJCn. After the reaction, vessel
had cooled to room tcmpcratur~, OR grams of an hydrous
; lithium chloride and 2.1~41 grams (0.006269 mole) of sublimed
2,2'-dibromobcnzidine were add while maintaining a positive
nitrogen pressure. The reaction vessel was fitted with a
thermometer and a rubber stopplc and 45 mls. of an hydrous
distilled N-methylpyrrolidone (NIP) and 45 also of an hydrous
distilled tetr~methylurea tTMU) were carefully added with the
aid of syrinxes. The resulting mixture was stirred and
Jo warmed to 40C until all solids had dissolved. The solution
was when cooled in a bath of ice and salt Jo a temperature
of -5C. A small amount of lithium chloride precipitation
was observed. Recrystallized to p,p'-stilbene dicaxbonyl
chloride (1.9129 grams; 0.006269 mole) was quickly added by
moans ox a tunnel to the stirred 2,2'-di~romobenzidine soul-
Al lion. An additional 30 mls. of NMP/TMU mixture (1:1 by weight),
at a temperature of 25C, were added through the funnel to thyroxine mixture. The temperature of the reaction mixture
did not rise above a temperature of 5C and then dropped
rapidly to 3C. After stirring for 30 minutes, the rewaken
mixture began to thicken and streaming birefringence (but not
stir opalescence) was observed. Lithium carbonate (0~92G gram,
0.01254 mole) was added and stirring was continued for an
additional 30 minutes a 0C.
The ice bath was removed from the reaction vessel,
and when the temperature reached 20C yin 30 minutes), tune
reaction solution had become sufficiently viscous as to begin
I
!
it `
to climb the shaft of the mechaslical circa A maximum
Rio t~n-i~cra~ul-c of 55C way reached. Stirring was
stopped and the mixture was heated overnight at a temperature
of 55C. The reaction product a viscous polymer solution ox
3% wt./vol. concentration (three grams of polymer per 1~0 mls
of reaction solvent) was diluted with 130 mls. of I wt./vol.
lithium chloride in dimethylacetamide. The resulting polymer
solution was poured into 200 mls. of ice and water in a
blender. The resulting fibrous solid was filtered and washed
(in the blender) twice each with water, acetone and ether.
The product was dried in a vacuum oven at 15 mm. pressure and
90C or 18 hours. The polymeric product, obtained in 100%
yield, was a vex light-yellow fibrous solid having the
following recurring structural units:
,.
C C = I C-N N
By
The inherent viscosity of a polymer solution (0.5
gram of the polymer of Example 7 per 100 mls. of a solution
of five grams lithium chloride per 100 mls. of dim ethyl-
assumed) was 9.04 dl./gram at 30C. The molecular weight
, 20 of the polymer, as determined by light smatterings, was
¦ , 1.95 x 106, and be gel permeation chromatography, 8.71 x 105.
the molecular structure OX the polymer was confirmed
¦ l by infrared spectroscopy. Inspection of the ultraviolet/visible
spectrum of the polymer (in 5% wt./vol. lithium chloride'
1 25 dimethylacetamide~ showed a Max ox 352 no (E = 66,000) j ire
absorption peak at 368 no (I = 52,~00) and an extremely woe.
tail at 400 no.
-69-
~lcmcntal analysis for I r2N2O2 provided
philology:
~C Libra ON JO
I,
Calculated: 5~.56 3.1627.83 ~.88 5.57
Found: 5~.50 3.2227.94 4.87 5.47 (by difference)
Thermog~-avime~ric analysis showed that the onset of
degrada~ioll of ho polymer of example 7 occurred at 470C in
nitrogen and at 515C in air. Differential scanning calorie
metro and thermal mechanical analysis of film samples detected
a reproducible transition at about 225C.
Polymeric films were prepared from the polymeric
lo material ox Example 7 by casting (onto glass plates) solutions
of the polymeric material in a I wt./vol. solution of lithium
chloride and dimethylacetamide (five grams lithium chloride per
100 mls. of dimethylacetamide). The concentration of polymer
ranged prom l to 5% wt./vol., i.e., from one gram to five grams
polymer per lo mls. of the lithium chloride/dimethylacetamide
; solution. In each instance, the glass plate carrying the
puddle-c~st polymer solution was immersed in water wafter
minimal evaporation o. solvent). The polymer was observed to
gel and a transparent and colorless unwarranted film separated
from the soaked glass plate. The resulting film was soaked
for several hours in water to effect extraction of occluded
lithium chloride and solvent, soaked in acetone and dried in
a vacuum oven at 90C and 15 mm. pressure. Refractive index,
measured by interferometry,was 2.03.
Stretched polymeric films were prepared in the
following manner. Water swollen films (obtained by soaring
the polymer films for several hours for removal of occluded
lithium chloride and solvent as a~oredescribed) were cut Lowe
strips. The strips were mounted between the jaws of a
mechanical unidirectional stretcher. The strips were Starr
!
- 7 o -
., ... , . , .. . . . . . .. . . _ .... _ . _ ...
_,. I, ,_. .
(in air at 220C) to about 55 to 55~ elongation, to coquette
film oricn~a~iol~. The stretched films jerk optically runs
parent. Infrared dichroism indicated that the stretched
films crook less than 65~ by weicJht oriented, the modulus was
3~9 x 106 pi Wide-angle X-ray analysis ox the films
showed crystallinity to be less than 10% by weight. Bircfrin-
Al genre, measured with the aid of a quartz wedge, was 0.589.
! Solutions of thy polymer of Example 7 in lithium
chloride/dimethylacetamide, as aforedescribed, were formed
into extruded films by tile "wc~-jct" method whereby the soul-
lion of polymer is extruded into an aqueous coagulation bath
I for golfing of the polymer material. The resulting trays
parent, colorless film strips were soaked in water and cut to
about 1 Jo 2 inches ( 25.4 to 50.8 mm.) for testing. The
partially oriented strips of film produced by the extrusion
I were further oriented by stretching in the manner described; in the Examples hereof Stretching was effected in air at a
temperature ox 180C. Elongation was to the break point, in
; the range of about 40~ to So the stretched strips were
optically transparent. Infrared dichroism indicated that the
films were 85% oriented. Measurement of birefringence utilizing
i a quartz wedge provided a birefringence value of 0.977. Measure-
mint my resort to interferometry provided a value of 0.865.
EXAMPLE
1 25 This example illustrates the preparation of posy
(2,2'-dibromo-4,4'-biphenylene~-_rans- -bromo-biphenylene
I dicarboxamide and the preparation therefrom of birefringnet
¦ polymeric films
¦ A 50-ml. reaction vessel (a resin-making kettle
¦ 30 equipped with a mechanical stirrer, a pressure-equalizing
dropping funnel, a nitrogen inlet tube and calcium chlsri~e
-71~
L
drainage Tokyo was h~2tcd Chile simul~alleously Lang the
vessel with nitrogen. After the reaction vessel had cooled
owe room temperature, 1.5 grams of an hydrous lithium chloride
and 0.4779 gram ~0.001397 mole) of sublimed 2,2'-dibromo-
i 5 benzidine were added while maintaining a positive nitrogen
pressure. The reaction vessel was pitted with a thermometer
and a rubber supply and it mls. of an hydrous distilled N-
methylpyrrolidinone (NIP) and five mls. of an hydrous distilled
tetramcthylurea (MU) were carefully added with the aid of
I syringes. The resulting mixture was stirred and warmed to
40C until all solids had dissolved. The solution was then
cooled in a bath of ice and salt to a temperature of 0C. A
small amount of lithium chloride precipitation was observed.
Recrystallized ~-bromo-p,p'-stilbene dicarbonyl chloride
(0.5366 gram; 0.001397 mole) was quickly added by means of a
funnel to the stirred 2,2'-dibromobenzidine solution An
additional ten mls. of MU (at a temperature of 25C) were
added through the funnel to the reaction mixture. The tempera-
; lure of the reaction mixture did not rise above a temperature
of 4C. After stirring for 15 minutes, the reaction mixture
began to thicken and streaming birefringence (buy not stir
opalescence was observed. Stirring was continued for an
additional 30 minutes at 4C.
The ice bath was removed from the reaction vessel
and the temperature was observed to rise to 25C in 90
minutes at which point the reaction mixture had become
sufficiently viscous as to climb the shaft of the mechanical
stirrer. Over the next 90 minute, the very pale-yellow
reaction mass was gently warmed with intermit tat stirring
the maximum temperature reached was approximately 70C.
-72-
:
; The reaction product, a I wt./vol. ~olyllleL oily
(three yearns ox polymer per 100 mls. of reaction solvcn~) was
; cooled to 40C and poured into 200 mls. of ice-water in a
j blender. The resulting fibrous solid was filtered and washed
(in the slender) twice each with water, acetone and ether.
The product was dried in a vacuum oven at 15 mm. pressure
¦ and ~0C or 13 hours. The product, ob~aincd in 95.4!~ yokel,
I, was a light-yellow fibrous polymeric material having the
following recurring structural units:
o If
The inherent viscosity ox a polymer solution (0.5
gram of the polymer ox Example 8 per 100 mls. of a solution
of five grams lithium chloride per 100 mls. of dim ethyl-
acetamide) was 7~81 dl./gram at 30C.
Molecular structure was confirmed by infrared
spectroscopyO Elemental analysis for C28H17N2Br3O2 provided
the following:
I _ OH _ Brie ON JO
Calculated: 51.478 2~604 36.724 4.289 4.90
Found: 51.17 2.80 34.~2 4.15 7~06 my doffers)
Polymeric films were prepared from the polymeric
material of Example 8 by casting (onto glass plates) solutions
ox the polymeric material in a 5% wt./vol. solution of lithium
chloride and dimethylacetamide (five crams lithium chloride
per 100 mls. of dimethylacetamide). The concentration of
polymer ranted from 0.5 to I wt./vol., i.e., from 0.5 gram
to 5 grams polymer per 100 mls. of the lithium chloride/
dimethylacetamide solution. In each instance, the glass
plate carrying the puddle-cast polymer solution was immersed
in water (after minimal evaporation of solvent). The polymer
-73-
_ .1
was observed Jo gel and a transparellt and colorless unranked
film separated prom tic socked lass plate. Tile rc~ultillg
film was soaked for several hours in waler Jo effect extraction
of occluded lithium chloride and solvent, soaked in acetone
and dried in a vacuum oven at ~0C and 15 mm. pressure.
Refractive index, measured my inter~exomctry, was 2.07.
Stretched polymeric films were prepared in the
following manner. Watcr-~wollcn films (obtained by soaking
the polymer films for several hours for removal of occluded
lithium chloride and solvent as aforcdcscribed) were cut into
strips. Toe strips were mounter between the jaws of a
mechanical unidirectional stretcher. The strips were stretched
(in air it 220C) to about 60~ to 65~ elongation, to effect
film orientation. The stretched strips were optically trays-
parent. Birefringence, measured with the aid of a quartz
wedge, was 0.680.
Solutions of the polymer of Example 8 in lithium
chloride/dimethylacetamide, as aforedescribed, were formed
into extruded films by the "wet-jet" method whereby the
solution ox polymer is extruded into an aqueous coagulation
bath for golfing ox the polymer material. the resulting
transparent, colorless film strips were soaked in water and
cut to about 1 to 2 inches (25.4 to 50.8 mm.) for testing. The
partially oriented strips of film produced by the extrusion
were further oriented by stretching in the manner described
in the Examples hereof. Stretching was effected in air (at a
~empcra~ure ox 180C) Jo the break point, in the range ox
about 40% to 50~ elongation. The stretched film strips were
optically transparent. Measurement of birefringence utilizing
a quartz wedge provided a birefringence value of 0.~55. Measure-
mint my resort to interferometry provided a value of 0.849.
-74-
t
EXAMPLE 9
.
This example illustrates true preparation of posy
` (2,2'-dibromo-4,4'-biphenylene)-~,a'-dimethylmuconnomad and
! the preparation therefrom of birefringent polymeric films
A 50-ml~ reaction vessel (a resin-making kettle
quipped with a mechanical stirrer, a pressure-equalizin~
f~rGplJin~J urea at, a rli~rocgcl~ inlet lube, and calcium chloride
drying tube) was heated while simultaneously flushing the
v~s~l with ni~roycn. After the reaction vessel had cooled
to room temperature, C.4 gram of an hydrous lithium chloride
lo all 0.8519 gram ~0.00249 mole) of sublimed 2,2'-dibromo-
benzidine were added while maintaining a positive nitrogen
pressure. The reaction vessel was fitted with a thermometer
; a rebuker stipple, and ten mls. of alluders distilled N-
me1-hylpyrrolidone to P) we're carefully added with the aid of
a syringe. The resulting mixture was stirred and warmed Tokyo
until all solids had dissolved. The solution was then cooled
in a bath of ice and salt to a temperature of OKAY with format
ion of ohmic, lithium chloride,_, precipitate. A solution or wrecker-
tallied dim ethyl muconyl chloride gram; 0.0024,91
mole) in six mls. of an hydrous, distilled tetrahydrofuran(T~F)
was added to the dropping funnel through a rubber stopper with a
syringe. The dim ethyl muconyl chloride/THF solu~lon,
the temperature of which was 25C, was added drops o'er
five minutes to the cold 2,2'-dibromobenzidine solution white
~tirrincJ~ moderately. The addition funnel was rinsed w oh
six my Or' Nil' which was alto addled dropwisc to ho rcic~_io,
ix,;urc ill order to prevent the temperature of the rcacsio~
mixture from rising above 1C. After stirring for one Gore
Jo during which time the solution turned lemon-yellow us did
not thicken), 0.354 gram of solid lithium carbonate way added
-75-
I
¦ all at once Jo ho reac~icn mixture. Within ten minutes
`! nuzzle ~hickeninc~ was observed and after an additional
, I minutes, at 20C, the viscosity increased further. The
' ice bath was removed from the reaction vessel and the tempera-
-lure of the reaction mixture was allowed to rise to
25C over a one-hour period during which time a thick paste
Lowe wormed. 'Lowe ~empcrature ox the reaction mixture was
I increased Jo 65C over the next 20 minutes producing a
mix~urc Welch could no longer be stirred. Additional heating
for 18 hours at 55C without stirring produced a transparent,
Lyle viscous polymer solution. The reaction product,
a 5.36~ wt./vol. polymer solution (5.36 grams of polymer per
100 mls. of reaction solvcn~) was observed to exhibit con-
siderable streaming birefringence upon application of low
' 15 mechanical stress; stir opalescence was not, however, observed.
I The polymer solution was poured into a blender
;' COntaininCJ 200 ml. ox ice-wa~cr and the resulting; fibrous
solid was filtered and washed (in the blender) twice each
i with water, acetone and ether. The product was dried in a
vacuum oven at 15 rum. pressure and 90C or 13 hours. The
product, obtained in 94.7~ yield, was a white fibrous polymeric
nla~crial having the following; recurring structural units:
13 if if o if r
t C - C = C -- C = C -- C -- N N
SHEA By
'I C inhere Vim ox my old a polylne~r solute ion
(owe grams of the polymer of Example 9 per 100 mls. ox a
solution of five grams lithium chloride per 100 mls. or
dilnc~hylacc~amidc) was Go dl./gram at 30C.
-76-
I
Molecular structure was confirmed by infrared
I¦ spec~roscopy. Inspection of the ultraviolet/visible absorption
! spectrum for the polymer of Example 9 (in 3j wt./vol. lithium
chloride/dimethylacetamide showed a Max I 333 no = 33,600)
and an extremely weak tail at 400 no.
Elemental analysis for Clue 3r2~l22 P
, Jo 1 tow i~lCJ:
¦ I OH Brie ON JO
Calculated: 50.448 3.387 33.562 5.883 6.72
Issue 50.0~ 3.~5 3~.17 5.7~ Go (my ~i~Ecr~-,c~
hcrmogr?vime1ric analysis showed what the onsc~ ox
degradation occurred at 360C in ni~rogcn and at 310C in air.
Differential scanning calorimetry and thermal mechanical
i~n~lysis of film samples showed a reproducible transition at
about 185C.
Polymeric films were prepared from the polymeric
material ox Example g by casting (onto glass plates) solutions
ox tune polymeric material in a I wt./vol. solution of lithium
chloride and dimethylacetamide (five grams lithium chloride
per 100 mls. of dimethylacctamide). The concentration ox
polymer ral~g~d prom 2 to Jo wavily., i.e., from two grams
to four yams polymer per 100 mls. of the lithium chloride/
dllllo~llylac~alnide slyly. in each instance, the glass pluck
carrying the puddle cast polymer solution was immersed in
water (after minimal evaporation of solvent). The polymer
film was observed to gel and a transparent and colorless
ulloriell~ed film separated prom the glass plate. The resul~inc3
Film was socked for several hours in water to effect cx~rac-
Shea of occluded lithium chloride and solvent, soaked
30 Salk and dried in a vacuum oven at 90C and 15 on. wrier.
Refractive index, measured by interferometry,was 1.~1.
-77-
s Lo
¦ Stretched polymeric films were prepared in the
! ~ollowil~c; manner. Water-swollen films (obtained by soaking
¦ the polymer films for several hours for removal of occluded
I lithium chloride and solvent as aforedescribed) were cut into
¦ 5 strips. The strips were mounted between the jaws of a
ccll~nic~ reacher and were unidirectionally stretched,
,¦ ~ucco~ivcly, in steam, acc~onc and boiling e~hylcnc ylycol
(all of which function as plasticizers). The strops were
¦ stretched to an elongation of from 35% to 45~. The film trips
LO were further elongated (up to 60~) by stretching in air at
, 200C. Thy stretched strips were optically transparent. Optical
;, retardation was measured with a calibrated quartz wedge; film
thickness was measured with a micrometer. Birefringence,
I measured by means ox a quartz wedge, was 0.40.
EXPIMPLE 10
, For purposes of comparison with the substituted
i polyamides of the present invention, an unsubstituted polyp
a e was prepared and evaluated in the following manner.
i A solution polymerization reaction for the production
of poly(p-benzamide) was conducted in accordance with the
hollowing reaction scheme:
O
O = S = N C Of Lick Lowe- >
n
¦ A 50-ml~ reaction vessel (a resin-making kettle
¦ e~lull~le~ with rnech2nical stirrer, nitrogen filet lube an
calcium chloride drying tube) was heated while sommeliers I
¦ Lowe he vessel with nitrocJen. After the recline vex
i had cooled to room temperature, 40 mls. of an hydrous d~s~lllec
I -78-
era methyl urea (TAO), 8.0~ trams (0.04 mole) of vacuum-
¦ distilled p-thionylaminobenzoyl chloride and 0.52 yam
1 (0.012 mole) of lithium chloride were added while Mouton;
'I a positive nitrogen pressure. The resulting reaction mixture
Al 5 was stirred for ten minutes at room temperature and l.G8 yearns
(0.0~ mole) of lithium hydroxide MindWrite were added white
vigorously stirring. The reaction mixture was when stirred
or one hour at room temperature. After a period of seven
additional minutes, the reaction mixture became cloudy an
we_ o~rvcd Jo ~hickcn. the L~olymcric reactiorl product,
Err 20 milks, tl~ickcncd su~icicntly Jo adhere ho aye
of the mechanical stirrer. Tory only hour, the reaction
mixture, which could not be stirred, was heaved. on additional
flu y (14 my ox 'Lou way added a which point the
I reaction mixture still could not be stirred. The reaction
mixture was then heated Jo 130C without stirring. After
, two hours of heating at 130C, pliability of polymeric
I iOJl 111~ increased an ho product appeared to have
partially dissolved. Two reaction product was stored in the
reaction vessel overnight and was washed with water, filtered
and washed with acetone then ether. The product, posy
(p-bcn~amide) was dried in a vacuum oven at 80~C or two hours,
The inherent viscosity of a polymer solution of
poly(p-benzamide) in sulfuric acid was 1.60 dl./gram at 30C.
I Polymeric Elm of poly(p-bcnzamidc) were prepared
by casting a solution of the polymeric material in a 56 wt./vol.
solution of lithium chloride and dimethylacetamide (five trams
lithium chloride per 100 mls. of dimethylacetamide). The
concentration of polymer was 5Q~ wt.jvol., i.e., five yam
JO l.olymcr par 100 also ox the lithium chloride/dime~hyl~cetaml~e
-79-
solution. The cast polymer film was dried in a vacuum oven
a 90C (30 in. Hug) overnight. The polymer film was an
opaque, White flexible film Additional films were formed
by puddle-casting the solution as a~orcd~scribed onto glass
plates In each instance, the glass plate carryincJ the
puddle-cast polymer solution was immersed in water (after
most ox the solvent had evaporated). The polymer film which
separated from the glass plate was a tough, transparent,
~lcxiblc film. The resulting film was sucked or several
10 hours in waxer to effect extraction of occluded lithium
chloride and solvent.
Stretched polymeric ills were prepared if, the
~ollowislcJ manner. Wa~cr-swollcn films (obtained by oily
the polymer films or several hours or removal of occluded
lithium chloride and solvent as aforedescribed) were cut into
strips. The strips were mounted between the jaws ox a mechanic
eel richer aloud ware unidirectionally s~re~ched, successively,
in skim and in air (at 200C). The strips were stretched to
an elongation of approximately pow. The resulting stretched
films ware clouded in appearance. Optical retardation was
measured with a calibrated quart wedge; film thickness WAS
measured with a micrometer. Birefringence, measured by means
ox a quart wedge, was 0.23.
By inspection of ho valves ox biro ~ringc:s,cQ
described it coslnection with the substituted polyamides of
Lo TV Lo ' I ; ho I
it can be seen that the birefringence of poly(p-bcn~.~midc)
of collpar~tive ~xaml~le 10, was, in general, decidedly lower.
-80~
I~XAM?LE: 11
I This employ illustrates the pxeparatlon Go polo-
;! [2,2'-bis(trifluoromethyl)-4,4'-biphenylenc]-transsup
stilbene dicarboxamide and the preparation therefrom of
birefringent polymeric films.
loo rnl. rcac1:ion vassal (a rcsin-makinc~ kc~tlc
¦ equipped with a mechanical stirrer, nitrogcll into lube and
calcium chloride drunk tube) was heated while simultaneously
flushing the vessel with nitrogen. After the reaction vessel
ha cooled to room tcmpcra~urc, 1.5 Crimea of an hydrous lithium
chloride and 0.5171 gram (OKAY mote) of recrystallized
¦ 2,2'-bis(trifluoromethyl)-benzidine were added while main
twining a positive nitrogen pressure. The reaction vessel was
it'd with a thermometer end a rubber stol~plc and ten mls.
of an hydrous distilled N-methylpyrrolidon~ (NIP) and ten mls.
of an hydrous distilled tetramethylurea (MU) were carefully
I added with the aid of syrinxes. The resulting mixture was
stirred and warmed to 40C until all solids had dissolved.
The solution was then cooled in a bath of ice and salt to a
I temperature of -5C. A smell amount of lithium chloride
precipitation was observed. ~ccrystalli~cd trans-p,p'-
stilbene dicarbonyl chloride (0.4923 gram; 0.001615 mole) was
carefully added by means of a funnel to ho stirred 2,2'-
bis(trifluoromcthyl)-ben~idinc solution. on additional 10 mls.
of MU, at a temperature of 0C, were added through the funnel
to the reaction mixture. Tic temperature of the reaction
mixture did not rise above a temperature of 5C and then
roll rapidly to -3C. r s~irril~cJ or 30 monks, the
reaction mixture began to thicken and streaming birefringence
(but not stir opalescence) was observed. Stirring was continued
for an additional 30 minutes at 0C.
-81~
The ice bath was removed from the reaction vessel,
an when the temperature reached 20C (in 30 minutes), the
reaction solution had become very viscous. Over the next 75
minutes, the completely colorless, transparent solution was
warmed to 72C. After stirring at this temperature for the
Nat 18 hours, the mixture was cooled to 40C. The resulting
polymer solution was poured into 200 mls. of ice and water in
a blender. The resulting fibrous solid was filtered and washed
(in the blender) twice each with water, acetone and ether. The
product was dried in a vacuum oven at 15 mm. pressure and 90C
' for 18 hours. The polymeric product, obtained in 99.5% yield,
was a very liqht-yellow fibrous solid having the following
recurring structural units:
C C = C I} I
i 15 Thy inherent viscosity of a polymer solution (0.5
gram of the polymer of Example 11 per 100 mls. of a solution
ox jive grams lithium chloride per 100 mls. of dim ethyl-
acetamide) was 4.735 dl./gram at ~0C. The molecular structure
of the polymer was confirmed by infrared spectroscopy.
Elemental analysis for C30H18F6N2O2 p
~ollowill~J:
I Al Jo ON I
Calculated: 65.22 3.28 20.64 5.07 5.79
Found: 64.54 3.76 19.04 4.85 7.81 (by difference)
'l'hermogravimetric analysis showed that the onset ox
degradation of the polymer of Example 11 occurred at 500C ii,
I nitrogen and at 410C in air. Differential scanning Clara-
! metro and thermal mechanical analysis of film samples dctcc~c~i
a reproducible transition at about 185C.
-82~
Polymeric films were prepared from the ~ol~Jmcric
material of Example 11 by casting (onto glass plates) solutions
of tune polymeric material in a 5% wt./vol. solution of lithium
chloride and dimethylacetamide (five grams lithium chloride
per 100 mls. of dimethylacetamide). The concentration ox
polymer ranged from 1.0 to I wt./vol., i.e., from 1.0 gram
to five grasps polymer per 100 mls. of the lithium chloride/
Al dimethylacetamide solution. In each instance, the gloss plate
'I carrying the puddle-cast polymer solution was immersed in water
l 10 (attacker minimal evaporation of solvent). The polymer film was
if observed to gel and a transparent and colorless unwarranted
film separated from the glass plate. The resulting film was
soaked for several hours in water to effect extraction of
¦ occluded lithium chloride and solvent, soaked in acetone and
dried in a vacuum oven at 90C and 15 mm. pressure. Refractive
index, measured by interferometry, was 1.997.
I Stretched polymeric films were prepared in the
I lollowill~ millionaire. Water-swollen films (obtained by soaking
the polymer films for several hours for removal ox occluded
lithium chloride and solvent as aforedescribed) where cut into
strips. The strips were mounted between the jaws of a
o~lla~lical ul~idirectiol~al stretcher. 'Lowe strips were stretched
(in air at 220C) to about 60 to 65% elongation, to effect
! film orientation. The stretched films were optically trueness
parent. Birefringence, measured with the aid of a quartz
wedge, was 0.537.
Solutions of the polymer of example 11 in lo us
chloride/dimethylacetamide, as aforedescribed, were formed
into extruded films by the "wet-jet" method whereby the Swahili
lion of polymer is extruded into an aqueous coagulation bath
-83-
Jo I
for golfing OX the polymer material. The resulting trays-
L~ren~, colorless film strips were soaked in water and cut to
about 1 to 2 inches (25.4 to 50.8 mm.) for testing. The
aureole oriented strips of film produced by the extrusion
wore further oriented by stretching in the manner described on
the Examples hereof. Stretching was effect to an elongation
I of less than 20~. The stretched strips were optically trays-
Z parent. Infrared dichroism indicated that the films were 92
Al oriented. Measurement of birefringence utilizing a quartz
wedge provided a birefringence value of 0.879.
EXAMPLE 12
This example illustrates the preparation ox polyp
'I [2,2'-bis(trifluoromethyl)-4,4'-biphenylene]-2,2'--dimethoxy-
I ~,4'-biph~nyl and tune preparation thcrcErom of bircfrin~ent
polymeric films.
' A 100 ml. reaction vessel pa resin-making kettle
j equipped with a mechanical stirrer, a pressure-equalizing
I drop in funnel, a nitrogen inlet lube all calcium chloride
! dry lube) was healed white simul~ancously flushing the
Z 20 vessel with nitrogen. After the reaction vessel had cooled
to room temperature, 3.0 grams of an hydrous lithium chloride
aloud 0.4328 yam (0.001352 mote) of recrystallized 2,2' bus
(trifluoromethyl)benzidine were added while maintaining a
¦ positive nitrogen pressure. The reaction vessel was fitted
with a thermometer and a rubber supply and 20 mls. of ashy-
dross distilled N-methylpyrrolidinone (NIP) and 20 mls. of
j an hydrous distilled tetramethylurea (MU) were carefully added! w i l h the aid of .syrin~Jcs. The resulting mixture was stirred
and warmed to 40C until all solids had dissolved. The Swahili
ion WAS howl cooled in a bath of ice and so to a ~cm;~cra~urc
'
I
or or C. A mull amount of lithium chloride precipitation was
observed. recrystallized 2,2'-dimethoxy-4,4'-biphcnyldicarbonyl
chloride (0.4586 gram; 0.001352 mole) was quickly added by
means of a funnel to the stirred 2,2'-bis(trifluoromcthyl)-
I bcl~idille solutioll. on additional 20 mls. of MU (at temperature of 0C) were added through the funnel to the
reaction mixture. The temperature of the reaction mixture
did not rise above a temperature of 5C. After stirring for
30 minutes, the reaction mixture began to thickly all turned
milk-like in appearance. Stirring was continued for an
additional 30 minutes at 0C.
Thy ice bath was removed from the reaction vessel
and the temperature was observed to rise to 20C in 30 minutes
at which point the reaction mixture was viscous and opaque.
Over the next 75 minutes, the opaque reaction mass was gently
warmed to 40C at which point it became transparent. After
stirring at this temperature for the next 18 hours, the
reaction mixture was cooled to 30C and poured into 400 mls.
of ice-water in a blender. The resulting fibrous solid was
j]~rcd and washed (in the lander twice each with water and
ether. The product was dried in a vacuum oven at 15 mm. pressure
and 90C for 18 hours. The product, obtained in 99.3% yield, was
an off-white fibrous polymeric material exhibiting syllable
in acetone or tetrahydrofuran and having the following
recurring structural units;
3 U I N
The inherent viscosity of a polymer solutioil I awry
of the polymer of ample I per 100 mls. ox sOlUtlOf: Al- ' lo
-85-
trams lithium chloride per 100 mls. of dimethylacetamide) was
lug dl./gram aye 30C.
Molecular structure was confirmed by infrared
spectroscopy. Inspection of the ultraviolet visible spectrum
of the polymer (in I wt./vol. lithium chloride/dimethyl-
Eormamide) showed a Max of 316 no (I = 2-59 x 10 )-
Elemental analysis for C30H20F6N2O4 p
following:
I OH OF ON JO
alkaloid: 61.34 3.43 19.41 4.77 10.89
Found: 59.82 3.51 18.70 4.62 13.35 (by difference)
Thermogravinetic analysis showed that the onset of
degradation of the polymer of Example 12 occurred at 470C in
nitrogen and at 440C in air. Differential scannincJ colon-
lo metro detected a reproducible transition at about 180C.
Polymeric films were prepared from the polymeric
material of Example 12 by casting (onto glass plates) solutions
ox the ~olymcric malarial in a I wt./vol. solution of lithium
chloride and dimethylacet~mide ivy grams lithium chloride
or 100 my ox dimethylacetamidc). The concentration of
polymer ranged from I to So wt./vol., it from lug gram
to 5 trams polymer per 100 mls. of the lithium chloride/
dimethylacetamide solution. In each instance, the glues
slate c~rryl~cJ the pud~lc-cast polymer solution was immersed
in water (aster minimal evaporation of solvent). The polymer
was observed Jo gel and a transparent and colorless unwarranted
film separated from the soaked glass plate. The resultincJ
film was soaked or several hours in water Jo effect extraction
of occluded lithium chloride and solvent, soaked in acetone
and dried in a vacuum oven at 90C and 15 mm. pressure.
l~c~rac~ivc index, measured by interferometry, was 1.7;~
-86-
¦ Solutions of the polymer of example 12 in Lithuania
I chloride/dlmethylacetdmidc, as a~oredescribed, wore formed
into extruded illume by the "we~-jc~" method whereby the
I solution or polymer is extruded into an aqueous coagulation
5 byway or elan of the polymer material. The resulting
transparent, colorless film strips were soaked in water and
cut to about 1 to 2 inches (25.4 to 50.8 mm.) for testing. The
partially oriented strips ox film produced by the extrusion
! were further oriented by stricken in the manner described
in the Examples hereof. Stretching was effected in air (at a
! temperature of 180C) to an elongation of less than 20~. The
stretched film strips were optically transparent. Infrared
! dichroism indicated that the films were 92% oriented. Measure-
mint of birefringence utilizing a quartz wedge provided a
i 15 bircfrin~ cc value of 0.586.
! AMPLE 13
This example illustrates the preparation of polyp
[2,2',3",2"'-tetrakis(trifluoromethyl)-1,1':4',1"::4",1"':4"'-
~uatcrphenylene]-trans-p,p'-stilbenedicarboxamide and the
preparation therefrom of birefringent polymeric films.
A 100 ml. reaction vessel (a resin-making kettle
equipped with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
flushing the vessel with nitrogen. After the reaction vessel
I had cooled to room temperature, lo grams of an hydrous lithium
chloride and 0.5806 gram ~0.0009543 mole) of recrystallized
4,4"~diamino-2,2',3",2"'-~etrakis(trifluoromethyl))-1,1':4',
1":4",1"'-quatcrphcnyl ware added white maintaining a IJositivc
nitrogen pressure. The reaction vessel was fitted with a
~hernlolnc~cr and rubber ~Oi~plc and ten mls. ox an hydrous
I
.~æ~
distilled N-methylpyrrolidone (NIP) and ten mls. of an hydrous
distilled tetrame~hylurea (MU) were carefully added with the
aid of syringes. The resulting mixture was stirred end warmed
to 40C until all solids had dissolved. The solution was then
cooled in a bath of ice and salt Jo a temperature ox -5C. A
small amount of lithium chloride precipitation was observed.
~ccry-~tallL~ed ~ran_-p,p'-s~ one dicarbonyl chloride (0.2909
gram; 0.0009543 mole) was carefully added by means of a funnel
Jo the stirred diaminoquaterphenyl solution. An additional 10
mls. ox MU, at a temperature of 0C, were added through the
funnel to the reaction mixture. The temperature of the reaction
mixture did not rise above a temperature of 7C and then
dropped rapidly to KIWI After stirring for 30 minutes, the
reaction mixture began to thicken and streaming birefringence
(but not stir opalescence was observed. Stirring was continued
for an additional 30 minutes at 0C.
The ice bath was removed from the reaction vessel,
and when the temperature reached 20C (in 30 minutes), the
reaction solution had become very viscous. Over the next 75
minutes, the light yellow, opaque solution was warmed to 45C.
After stirring at this temperature for the next 18 hours, the
transparent polymer solution was poured into 200 mls. ox ice
and water in a blender. The resulting fibrous solid WAS filtered
and washed (in the blender) twice each with water and ether.
Lowe product was dried in a Vacuum oven at 15 mm. pressure and
90C for 18 hours. The polymeric product, obtained in 92.2%
yield, was a very light-yellow fibrous solid having the
lolJowjn(J recurring structural units:
Jo I! I = C C-N H
H CF3 CF3
-88-
lo
The inherent viscosity of a polymer solution ~0.5
gram of the polymer of Example 13 per 100 mist of a solution ox
five grams lithium chloride per 100 mls. of dimethylacetamide)
was 1~31 dl./gram at 30C. The molecular structure of the
polymer was confirmed by infrared spectroscopy. The polymer was
soluble in tetrahydrofuran, in acetone and in various aside-
type solvents, with and without added lithium chloride.
Elemental analysis for C~4H2~F12N2O2 p
following:
I OH OF ON %0
___ __,
Calculated: 62.86 2.8827.12 3.33 3.81
Found: 62.07 3.2924.18 3.16 7.3, (by difference)
Thermogravimetric analysis showed that the onset of
degradation of the polymer of Example 13 occurred at 510C in
nitrogen and at 440C in air. Differential scanning calorie
metro and thermal mechanical analysis of film samples detected
a reproducible transition at about 187C.
o]ynlcric film ware ~rcl~rcd prom the polymeric
material of Example 13 by casting (onto glass plates) solutions
of the polymeric material in a I wt./vol. solution of lithium
chloride and dimethylacetamide (five grams lithium chloride per
100 mls~ of dimethylacetamide). The concentration of polymer
ranged from 0.5 to I wt./vol., i.e., from 0.5 gram to five
grams polymer per 100 mls. ox the lithium chloride/dimetAyl-
acetamide solution. In each instance, the glass plate Corinth puddle-cast polymer solution was immersed in water (after
inilllal ~vaL~ra~ion ox solvcn~). 'Lowe ~olymcr film was observe
to gel and a transparent and colorless unwarranted film separated
prom the glass plate. The resulting film was soaked for several
hours in water to effect extraction of occluded lithium chloride
and solvent, soaked in acetone and dried in a vacuum oven a
90C and 15 mm. pressure. Refractive index, measured by inter-
~erometry, was 1.810.
-89-
Jo Lo
Stretched polymeric films were prepared in the
~ollowiny manner. Water-swollen films (obtained by soa~incJ
the polymer films for several hours for removal of occluded
lithium chloride and solvent as aforedescribed) were cut into
strips. The strips were mounted between the jaws of a mechanical
unidirectional s~rctchcr. 'Lowe strips were stretched in methanol
and then in air at 220C to effect film orientation. The
stretched films were optically transparent. Birefringence,
measured with the aid of a quartz wedge, was 9.87.
SAMPLE 14
This ex~nple illustrates the preparation of polyp
[2,2',3",2"'-tetrakis(trifluorome~hyl)-1,1';4',1";;4",1"';4"'-
quaterphenylene~terephthalamide and the preparation therefrom
ox birefrin~ent polymeric films.
A 100 ml. reaction vessel (a resin-making settle
equipped with a mechanical stirrer, nitrogen inlet tube and
calcium chloride drying tube) was heated while simultaneously
Lange eye vessel with nitrogen. After the reaction vessel
hod cooled to room temperature, 1.5 grams of an hydrous lithium
chloride and 0.6301 gram (0.001036 mole) of recrystallized
4,4"'-dianlino-~,2',3",2"'-tetrakis(trifluorQmethyyule,
1":4",1"'-quaterphenyl were added while maintaining a positive
nitrogen pressure. The reaction vessel was fitted with a
tllcrlllom~e~r art rubber Swahili and con mls. of an hydrous
~3is~illcc] N-mcthyl~yr~olidonc NO and ion mls. of an hydrous
distilled tetramethylurea (TAO) were carefully added with the
air of ~yrinyc~. the resulting mixture was stirred and warmed
to 40C until all solids had dissolved. The solution was then
cooled in a bath of ice and salt to a temperature of +5C.
A small amount of lithium chloride precipitation was observed.
--90--
Recrystallized ~erephthaloylchloride (0.2103 gram; 0.001036
mole) was carefully added by means of a funnel to the stirred
?, 2'-diaminoquaterphenyl solution. An additional 10 mls. of
MU, a a temperature of 10C, were added through the funnel
to the reaction mixture. The temperature of the reaction
mixture did not rise above a temperature of 10C awry then
dropped to 15C. After stirring for 30 minutes, the reaction
mixture began to thicken and streaming birefringence (but
not stir opalescence) was observed. Stirring was continued
for an additional 30 minutes at 10C.
The ice bath was removed from the reaction vessel,
and when the temperature reached 27C (in 30 minutes), the
reaction solution had become very viscous. Over the next 75
minutes, the light yellow, transparent solution was warmed to
40C. After stirring at this temperature for the next 18 hours,
the polymer solution was poured into 200 mls. of ice and water
in a blender. The resulting fibrous solid was filtered and
washed (in the blander) twice each with water and ether. The
product was dried in a vacuum oven at 15 mm. pressure and 90C
for 18 hours. The polymeric product, obtained inn yield,
was a white fibrous solid having the following recurring
structural units:
-I- C C-N N
CF3 CF3
The inherent viscosity of a polymer solution ~0.5
gram of the polymer of Example 14 per 100 mls. of a solution OX
five grams lithium chloride per 100 mls. of dimethylac_~àmlde)
was 6.55 dl./gram at 30C. The molecular structure of Jo
polymer was confirmed by infrared spectroscopy. the pox ye-
-91-
I
was very slightly soluble in acetone, in tetrahydrofuran and in
ethyl acetate and was soluble in amide-type solvents with or
without added lithium chloride.
Elemental analysis for C36H18F12N2 2 P
following:
"C TAO OF I
Calculated: 58.23 2.44 30.71 3.77 4.85
Found: 57.87 2.50 30.56 3.77 5.3 (by difference)
Thermogravimctric analysis showed that the onset of
degradation of the polymer of Example 14 occurred at 4~GC in
nitrogen and in air. Differential scanning calorimetry and
thermal mechanical analysis of film samples detected a repro-
educible transition at about 160C.
Polymeric films were pr~parcd prom the polymeric
material of Example 13 by casting (onto glass plates) solutions
of the polymeric material in a 5% wt./vol. solution of lithium
chloride and dimethylacetamide (five grams lithium chloride per
100 mls. of dimethylacetamide)~ The concentration of polymer
ranged from 0.5 to I Whitehall., isle from Grimm to five
grams polymer per 100 mls. of the lithium chlor1de/dimethyl-
acetamide solution. In each instance, the glass plate carrying
the puddle-cast polymer solution was immersed in water wafter
minimal evaporation of solvent). The polymer film was observed
to gel and a transparent and colorless unwarranted film separated
from the glass plate. The resulting film was soaked for several
hours in water to effect extraction of occluded lithium chloride
and solvent, soaked in acetone and dried ion a vacuum oven at
90C and 15 mm. pressure. Refractive index, measured by inter-
formatter, was 1.79.
-92-
Stretched polymeric films were prepared in ho
following manner. Water-swollen films (obtained by soaring ho
polymer films for several hours for removal or occluded Lowe
chloride and solvent as aforedescribed) were cut into strips.
The strips were mounted between the jaws of a mechanical unit
directional stretcher. The Sty:; pus were stretched (in air at
220C) to effect film orientation. The stretched films were
optically transparent. Birefringence, measured with the aid
of a quartz wedge, was 0.293.
lo Solutions of the polymer of Example 14 in lithium
chloride/dimethylacetamide, as aforedescribed, were formed
into extruded films by the wet jet method whereby the soul-
lion of polymer is eroded into an aqueous coagulation bath
for golfing of the polymer material The resulting transparent
colorless film strips were soaked in water and cut to about
l to 2 inches (25.4 to 50.8 mm.) for testing. The partially
oriented strips of film produced by the extrusion were further
oriented by stretching in the manner described in the Examples
hereof. Mcasurerncnt of birefringence utilizing a quartz wedge
provided a birefringence value of 0.44.
EXAMPLE 15
Geometric indices were determined for the repeating
Us s of polymeric materials having the following structure
11 r
wherein each X is hydrogen or a substituent as set forth in
the following 'Lubell I. In the case of each recurrincJ unit,
i en
the eccentricity factor l + e was calculated and is reported
in TABLE I. Bond and group polarizability tensors were
utilized to calculate a polarizabili~y matrix for each
-93-
repeat unit, the diagonalized form of the matrix providing
the X, Y and Z contributions to the us t polarizability
ellipsoid. axial polarlzabilltles, i.e., X, Y and Z, wore
utilized to calculate longitudinal and transverse eccentric-
vies of each repeat unit, thus, reflecting its symmetry.
~ccer.~ricity values were calculated utilizing the
following procedure. A polarizability and a corresponding
orthogonal coordinate system is assigned to each segment of
the polymer repeat unit. Literature values for group polarize
lo abilities arc uti~izcd from the literature, or where not
available, are constructed from bond polarizabilities.
Available Danube values were utilized herein or all cowlick-
Lyons. Bond polarizabilities are utilized to connect
segments where necessary. To determine the overall polarize
ability of the repeat unit, the coordinate system of the
segment at one end of the repeat unit is made coincident with
that of the adjacent segment by means of the appropriate
I .). rrh~ I I I ] I ah successive
segmelit Whitehall the last segment is reached- Mathematically,
this Lillian thaw the matrix ox ogle sogme~l~ must by pro- and
post-multiplicd by a transformation matrix:
I= T us To
where I is the polarizability of segment; T is the trays-
formation matrix; T-l is the inverse of T; and I is the
polarizability of segment 1 in the coordinate system of
segment 2. The value of I is then added to I and the
~ralls~ormation repeated. Lowe repeat unit polarizability
matrix is diagonalized, thus, providing a repeat unit
polarizability ellipsoid with three semi-axes, i.e.,
ox yard ~zz, where ox is the major polarizabillty an
is coincident with the polymer backbone.
-94-
AL
Literature-reported values of 25~ and 31, rcsiJec~
lively, were utilized in all calculations as representing the
dihedral angle between the phenol and carbonyl moieties and
the dihedral angle between the phenol and amino moieties,
respectively. Expcrimcn~ally determined values for the dihcdr~l
angle between each X-substituted phenol moiety were utilized
in all calculations and are reported in TABLE I. Mean
diameter values, D, and length, L, were obtained from space-
filling molecular models.
TABLE I
Substituent X Diameter Length if + elm
(Dihedral Angle) (D) J G
(20) 4.49 21.35 1.061 0.98g
(60) 4.61 21.35 1.206 1.21
Of
(72) 4.78 21.35 1.348 1.23
By
(75~) 4.83 21.35 1.388 1.~4
(~5) 4.91 21.35 1.428 1.26
c~3
(80) 4.90 21.35 1.496 L.33
SHEA
(71) 4.76 21.35 1.330 1.25
From the data presented in TABLE I will be observed
the influence of the nature of the X substituent relative to
a hydrogen atom as regards the reported dihedral angle and
ruling substantial non coplanarity between inter bonded
l~hcnyl rinks. DiEEerenccs in mean diameter and influence of the
nature of X substituents on mean diameter and eccentricity
factor, and correspondingly, geometric index G will also be
observed. Thus, it will be noted that the largest subs~ituell~s,
-95-
______~
i.e., -CF3 and I subs~ituents, corresponded with the lyrics
dihedral angles between inter bonded phenol groups or the
highest non-coplanari~y and, accordingly, recurrincJ unit
having such substituents show hush geometric index values.
For purposes of comparison, geometric index G was
alkaloid Jo. ho Roy Wilt of poly(p-phenylcrle)tere~ hat-
nil avid ha ~ollowin~J structure and the rcsul~s thereof art
reported in TABLE II. Dihedral angle values of 25 and 31 were
utili~cd for purposes ox calculation as in the case of the
arc us ox ~XAMl'LE 15.
N
31~
TABLE II
. .
Mean 1 + en
DiameterLenc-th
(Do (L) 1 + e G
T
4.43 12.45 0.978 0.621
As can be observed from inspection of the data
reported in TABLES I and II, the geometric indices for the
repeat units of the materials set forth in TABLE I are
considerably higher than the geometric index calculated for
Lyle yule ~r~lllLII~l~l~ AL Lyle 11.
EXAMPLE 16
Geometric indices for the recurring units of
lulled llavisly ho hollowing structure were calcula~cd.
Each X substituent was as indicated in TABLE III. Dihedral
angles From the literature were utilized in such calculation
Calculated geometric indices were compared with values of
oracle my inlum bircFri~lgcllcc for ho polymeric mocker
rcuorted in TABLE III. Theoretical maximum birefringencc
-96-
values (I Max) were obtained by plotting the orientation
function, calculated from infrared dichroism, against
experimental birefringence and extrapolating to 1004~
orientation. The results are set forth in TABLE III.
C~C C I Lowe on
25 31
TALE III
Subs~itucnt X
(Dihedral Angle) G Max
__
-By
(75) 1.21 1.2Q
-CF3
(80) 1.18 0.98
From the data presented in TABLE III, it will be seer.
that high values of geometric index G corresponded with high
values of Max For purposes of comparison, the theoretical
maxim birefrin~cnce value (I Max) for the recurring unit
of poly~p-phenylene)terephthalamide (having a G value of 0.621
c, as shown in TABLE II) was also determined. The resulting nix
value of 0.83 or poly(p-phenylene)terephthalamide was higher
1 h Jo l l Wow Us J r Lo L LX~III Lo J I: OWE: I; r i C i no I Via
0.621. This is believed to be the result of the highly
crystalline nature ox the poly(p-phen~lene)terephthalamide
nla~erial, whereas the geometric index G reflects the inherent
an isotropy of an isolated chain independent ox such macro-
scopic properties as morphology, density, color or the like.
The enhanced optical an isotropy exhibited by the
preferred substituted-aromatic polyamide materials utilized
in the optical devices hereof is believed to be the result of
-97
Lo
wrecked, rod-like uniaxial molecular structure ox con
knurls and the amorphous/crystalline ratio thereof. This
ratio typically ranges from about 10:1 to about 20:1~ In the
case of highly unidirectionally oriented phenyl-typei polyp
asides this ratio generally will be on the range of about 0.3:1.
The presence of crystallizes is generally detrimental
in polymeric materials adapted to utilization in optical
devices owing to light scattering and diminished transparency.
The non-cc~planarity bc~wccin substituted biphenyl rings,
resulting from starkly bulky groups on the ortho positions
of inter bonded phenol zings, raises the amorphous/crystalline
ratio to a range of about 10:1 to about 20:1. This permits the
EaJ~rica~ion of haggle oriented films and gibers exhibiting high
transparency in addition to high bireringence. The ring-
substituted biphenyl polyamides additionally exhibit enhanced
volubility and can be fabricated into colorless films or
fibers where desired.
~XAMI'LE 17
Geometric indices were del~irmined lion the repeating
units of polymeric materials having the following structure
I
whcL-cein each X is hydroyon or a subs~i~uent as sex o'er
hi followincJ TABLE IV. In Thea case of each recurrincJ unwell,
1 en
ho eccentrically factor + e was calculated and it roof
in lo IV. Bond and group polarizability tensor Wylie_
utilized to calculate a polarizabi~ matrix for ever
'Lotte unit, the diagonali~ed form of the matrix r
-98-
the X, Y and Z contributions to the unit polarizabili~y
ellipsoid. Axial polarizabilities, i.e., X, Y and z, were
utilized to calculate longitudinal and transverse eccPntrici-
ties of each repeat unit, thus, reflecting its Sinatra.
Eccentricity values were calculated utilizing the
I urn Skye forth in Lowe 15.
Li!cra~urc-rcl~or~d valves of 25 and 31, rc~L~cc-
lively, were utilized in all calculations as representing the
dihedral angle between the phenol and carbonyl moieties and the
dihedral ankle between the phenol and amino moieties, respect
timely Experimentally determined values for the dihedral angle
between each Substituted phenol moiety were utilized in all
calculations and are reported in TABLE IV. Mean diameter values,
D, and length, L, were obt~incd from space-filling molecular
models.
TABLE IV
Mean
Subs~ituc~ X Diameter Length I en
(Dihedral Ankle) (I G
.___ _
(20) 4.52 29.80 0.938 1.373
I ~.66 29.80 1.155 1.640
('12) 4.8~ 29.80 1.166 1.594
By
(75) 4.90 29.80 1.145 1.5~6
(~5) 4.99 29.80 1.271 1.685
CF3
(owe) 4.98 29.80 10286 1.7
SHEA
(71) 4.82 29.8~ 1.181 1.6_~
prom the data presented in TABLE IV e observed
the influence of the nature ox the X substituer~ Rowley
dl-ocJen Allen as recJards the reported dihedral angle an
-99~
.$
resulting subs~ntial non coplanarity between in~orbondcd
phcnyl rowers. erences in mean diameter and influence of ho
nature of X substituenls on moan diameter and eccen~rici~
favor, an correspondingly, geometric index G will also be
observed. Thus, it will be noted aye the largest subs~i~uen-~,
icky., -CF3 and -I substituents, corresponded with the largely
dihedral angles between inter bonded phenol groups or the
hicJhe~ non coplanarity and, accordingly, recurring units
having such subs~ituen1-s show high geometric index values.
I :XAMl'LI. I
ht-polarizinc3 device utili~iny a highly
birefringent polyamide material was constructed in the
following manner.
Sue of birefrinyent material was prepared from
the polyamide of example if, i.e., polyl2,2'-bis(trifluoro-
methyl)-~,4'-biphenylene]-trans-p,p'-stilbene dicarboxamide.
The sheet was prepared by the "wet-jet" extrusion method
described in example if. The resulting extruded polymer, in the
form of a partially oriented transparent colorless film, was
soaked in water and cut into strips. The strips were then
further oriented by stretching in air in the manner also desk
cried in Example if. A strip of the birefringent polymer
--100--
(having perpendicular and parallel indices of refraction,
respectively, of approximately 1.72 and 2.34 and an approximate
thickness of 25 microns) was embossed by contacting one surface
of the strip with a brass prismatic plate heated to a temperature
of 180C and pressing the heated plate onto the surface of the
film so as to provide a prismatic layer of birefringent material
generally shown in Figure 6 as layer 42.
Onto a sheet of transparent isotropic glass material
of approximately one-mm. thickness was poured a layer of polyp
chlorinated biphenyl, an isotropic material having an index of refraction of 1.654, available as Aroclor 1260~ from Monsanto
Company, St. Louis, Missouri. The prismatic layer of birefring-
en material, prepared as aforesaid, was placed onto the layer
of Aroclor. The prismatic layer was covered with a second layer
of Aroclor so as to embed the prismatic layer in Aroclor mater-
tat. A second sheet of glass was placed onto the Aroclor so as
to sandwich the birefringent and Aroclor materials between the
two pieces of glass. The resulting polarizer device was tested
for its light polarizing properties by placing the test device
and a second polarizer into the path of a light beam and by
observing the attenuation of light resulting from rotation of
the respective polarizers.
trade Mark
--101--
121~
EXAMPLE 19
This Example illustrates the preparation, in accord-
arc with the reaction sequence set forth herein before, of
4,4"'-dinitro-2,2',3",2"'-tetrakis-(trifluoromethyyule":
~",l"'-quaterphenyl and the corresponding immune compound.
Part A. - Preoaratio~ of buster lùorumethYl)-4,4'-
dinitro-l,l'-biphenyl
To a solution of 2-bromo-5-nitro-benzotrifluoride
l50 growers) in 100 mls. of dimethylformamide were added 45 grams
of activated copper and the mixture was reflexed for five hours.
The reaction mixture was cooled and poured into excess water.
The product, a brown precipitate, was filtered off, washed
with water and dried. Chromatography over silica gel provided
the product 2,2'-bis-(trifluoromethyl)-4,4'-dinitro-1,1'-
biphenyl which was recrystallized from ether as shiny yellow
prisms exhibiting a melting point of 140C.
Part B. - Preparation of 4-amino-2,2'-bis-(trifluoromethvl)-
,
` 4'-nitro-1,1'-biphenYl
;;~ In 50 mls. of methanol and 75 mls. o Tulane, 4.75
grams of the product from Part A were dissolved. The solution
was reflexed while a solution (2.1 grams of sodium hydrosulfide
in 50 mls. of water and 50 mls. of methanol) was added drops
over a 45-minute period. As shown by thin layer chromatography,
the reaction was completed 150 minutes after the addition. The
reaction solvents were removed in vacua. Water (100 mls.) was
added to the residue, and then extracted with ethyl acetate.
Jo
Lola -
~21~
The organic layers were washed with water, dried (assay) and
solvent removed 'Jo provide a yellow syrup-like liquid. Thin
layer chromatography showed a trace of the corresponding Damon
compound in the resulting product which was utilized without
purification in Part C as follows.
rewrote C - Preparation of 2.2'-bis-(trifluorome.hyl)-4-iodo-
4'-nitro-1,1'-biphenyl
The product from Part B (4.5 grams) was diazotized
Whitehall sodium nitrite and hydrochloric acid and the diazonium
salt solution was added slow' to a stirring solution of
potassium iodide (5 grams), iodine (1 gram) and water (10 mls.)
maintained at 0C. The temperature was allowed to r so to room
temperature and the reaction mixture was stirred for one-half
hour and then heated over a steam bath for one hour. The
reaction mixture was cooled, diluted with water, excess iodine
was destroyed by adding sodium bisulfite and extracted with
ethyl acetate. The ethyl acetate layers were washed with
aqueous sodium basalt and water, dried (Nazi) and vapor-
axed to provide a yellow low-melting solid. This was absorbed
on dry column silica gel. Elusion with benzene/hexane (l/2)g2ve
4.2 grams of 2,2'-bis-(trifluoromethyl)-4-iodo-4'-nitro-1,1'-
biphenyl and 0.15 tram of the Dodd compound. The desired
compound was crystallized as a pale yellow solid from methanol
and exhibited a melting point of 67-68C.
Part D. - Preparation of 4,4i'--dinitro-2,2',3",2"'~tetrakis-
. .
(tri~luoromethyl)-1,1':4',1":4",1"'-~_terphenAvl
Nine grams Go the compound from Part C were dissolved
in 20 mls. of dimethylformamide. Nine grams of activated copper
were added and the reaction mixture was reflexed under nitrogen
for 30 hours. The mixture was poured into water, the brown
- loll -
precipitate was filtered off, washed with waxer and dried. It
was extracted overnight in a Sexuality extractor with acetone and
the acetone solution was evaporated to provide a Yellow residue.
Chromatography over dry column silica gel and elm ion with
benzene/hexane (1/1) guy a white solid, crystallized as short
while needles from chloroEorm/methanol and exhibiting a melting
pullout ox 250-255C.
Purity. - Preparation of 4,4"'-diamino-2,2',3",2"'-tetxakis-
(trifluoromethyl)-1,1':4',1": 4 "_! a rphenyl
The compound from Part D hereof (4 yams) was well
minced with 11 grams of Snuck 2I~2O to which absolute ethanol
(10 mls.) was added and stirred while concentrated hydrochloric
acid (15 mls.) was dropped in carefully. The mixture was
reflexed overnight, ethanol was removed, water was added to
the residue and then made basic with guy sodium hydroxide. The
white precipitate was filtered off, dried and extracted over-
night in a Sexuality extractor with ethyl acetate. Removal of
solvent and recryst~lli anion of the residue from chloroform/
hexane gave the desired Damon compound as short white needles
exhibiting a melting point of 208-210~C.
I analysis fur Cliff 2 P
following
I go % 'OWE
Ccllcul~t~: 55.3 2.6 4.6 37.5
Found: 55.4 2.7 4.637.4
- loll -
