Note: Descriptions are shown in the official language in which they were submitted.
RD-5683
1~4304~Z
AROMATIZED POLYACETYLENES
This invention relates to aromatized poly-
acetylenes, i.e., polyacetylenes, either homopolymers or co-
I ~ polymers of diethynyl co~lpounds, wherein at least 15 percent
of the ethynylene groups of the polymer have been converted
to 3,4,5,6-tetrasubstituted 1,2-phenylene groups by reaction
with a 293,4,5-tetrasubstituted cyclopentadienone, herein-
- after called by the commonly abbreviated name - a
tetracyclone. More particularly, this invention reIates to
polymers whose repeating units have at least one of the
formulae: ;
.
(a? ~C - C-R-C -C~
~ -
. _
~ R-C -C- _
(b)
- R" R"
R - ~ ~
(c) ¦R;_ ~ -R' R~ R'
L R R R" R"
of which no more than 85% have formula (a)9 where each R is
the residue other than the ethynylene groups of a solvent
soluble acetylenic polymer whose repeating units have
formula (a), each R~, independently~ is lower alkyl, lower
~k
O
RD-5683
alkoxycarbonyl, phenyl or halophenyl and each R",
independently, is phenyl or halophenyl.
Polyacetylenes are relatively new polymers having
many interesting and desirable properties. They were first
described by Allan S. Hay in J. Org. Chem. 25, 1275 (1960)
and 27, 332~ (1962). Subsequently, a much broader class of
polyacetylenes was disclosed and claimed in Hay's U.S. patents
3,300,456, 3,332~916 and 3,594,175. Using Hay's process of
oxidatively coupling compo~nds having two acetylenic groups,
Sladkov et al. likewise prepared polyacetylenes which they
described in BU11. Acad. Sci.~ U. S . S . R. ~ Div . Chem. Sci.,
English Translation [7] 1220 (1963). All of these polymers
and copolymers described in this prior art have, as a common
property, a butadiynylene group, i.e., -C= C-C -C-, dispersed
along the polymer backbone~ They also ha~e in common the
fact that they are formed by oxidatively coupling of organic
compounds having two ethynyl groups, i.e., -C-- CH In the
,
; oxidative coupling reaction, thoroughly described by Hay in
his above patents and publications, the hydrogen is removed
from ~he ethynyl groups by the oxidation reaction ~o form
water ~nd one of the resulting ethynylene groups o~ one
molecule is joined to one of the resulting ethynylene groups
of another molecule to form the butadiynylene~groups of the
.
polymer molecule, It is these latter groups which cause the
polymers to be vPry thermally unstable and photosensitive and
--2--
.
.
~43UD4,Z RD~5683
which tend to make the polymer difficulty soluble in common
solvents for polymers.
It is obvious that these polyacetylenes are
entirely different in kind than polymers containing isolated
i!\ ~ ethynylene groups in the polymer molecule. Typical of such
polymers are the polyesters obtained by esteriication of an
acetylene dicarboxylic acid and a glycol or esterification
of a polycarboxylic acid with an alkynediol and polyethers
obtained by the reaction of acetylenic glycols with dialkyl
acetals or with alkyl halohydrins. These polymers have
ethynylene, but not butadiynylene groups, along the polymer
backbone. Such polymers are not included in ~he term poly-
.
acetylenes.
~ Hay, in his above patents, describes uses for the
polyacetylenes which make use of their thermal instability,
e.g., coating a substrate with a solution of the poly-
.
acetylene and thereafter thermally decomposing the coating
under controlled conditions to obtain a resistor of the
desired electrical properties. In his U.S. patent 39594,175,
he describes a means of increasing the sol~bility in common
solvents by either making the polyacetylenes from dipropargyl
ethers of dihydric phenols or copolymerizillg ~he diethynyl
compounds with the dipropargyl ethers. In the same patent he
also describes the very interesting application for the
polyacetylenes which make use of their photosensitive
--3--
RD-5683
1043~4Z ~
properties.
CoM~ Krutchen, in hls Canadian application, Serial
No.l26,040, iled October 26, 1971, describes means for
converting the polyacetylenes into fibers which are there-
after, because of their thermal instability, readily
converted into carbon or graphite fibers. Because of the
extremely high carbon content and because the thermal
decomposition can be carried out in a controlled fashion, the
polyacetylenes are readily converted into carbon and graphite
fibers ln a higher yield and by a more rapid process than can
the usual organic polymers previously used for making carbon
and graphite fibers. In my Canadian- application, Serial No.
; 1330623, filed February 1, 1972, I disclose a particular
terpolymer suitable for making the carbon and graphite fibers.
As this prior art shows, thQre are many uses and interesting
applications for the polyacetylenes. However, because of the
extremely high carbon content, it would be especially desir-
able if polymers could also be prepared having this same
high carbon content but not possessing the thermal instability.
It has been known for a long time that tetracyclones
would react with simple compounds containing one or two
ethynylene groups. Dilthey et al., ChemO ~er. 689 1159
(1935), describes the reaction of tetraphenylcyclone with
diphenylbutadiyne to give 2,3,4,5,6-pentaphenyltolane~ i.e.,
the tetracyclone reacted with one but not both of the
4-
1043Q4~ RD 5683
ethynylene moieties of the butadiynylene group. Ried et al.,
Chem. Ber. 93, 1769 (1960) likewise reacted tetracyclon s
with diphenylbutadiyne and obtained correspondin~ tolanes.
However, the same tetracyclones when reacted with compounds
containing two ethynylene groups separated by an intervening
carbon chain3 for example, an aromatic compound having two
ethynyl groups on different carbon atoms of the aromatic ring
could both be reacted with the tetracyclone. This was also
reported in a review article on the chemistry of cyclopenta-
dienones by Ogliaruso et al., Chem. Rev. 65, 261 (1965) on
page 337. However, in a later paper with Becker? J. Org.
Chem. 309 3354 (1965) 7 Ogliaruso reported that when
heated in a sealed tube to 325, two moles of tetraphenyl-
cyclone could be reacted with one mole of diphenylbutadiyne
to produce the corresponding octaphenylquaterphenyl.
Ogliaruso et al~ in J. Org. Chem. 28, 2725 (1963)
had prepared bistetracyclones and reacted them with two moles
of a compound containing one ethynylene group. Ried et al.
in an extension of their work mentioned above, reported the
fi~rst preparation of a-polymer by reacting a bistetracyclone
with a diethynyl benzene in Naturwiss. 53, 30~ (1966).
Stille and coworkers likewise reported the making of polymers
from bistetracyclones and diethynyl compounds in J. Polym.
Sci. A-l, 5, 2721 (1967) and extended this work to include
the polymers from bis-2-pyrones and diethynyl compounds in
-
1043~2 RD-5683
Macromol. 2, 85 (1969). A review of the work on the
cyclization of unsaturated compounds is found in a review
article on polyphenyls and polyphenylenes by ~peight et al.
in Rev. Macromol. Chem. 6, 295 (1971) beginning on page 354.
Although these polymers had the desired very high
carbon content, solubility in ordinary solvents and thermal
stability, they suffer from the fact that the required bis-
tetracyclones or bispyrones are extremely expensive since
they cannot be prepared from readily available materials
Al~hough many materials are known to readily react with the
ethynylene groups, I have unexpectedly found that the tetra-
cyclones form a unique class of compounds that can be
reacted with the polyacetylenes to produce thermally stabla,
solvent soluble polymers. Although the other materials will
.
react with the polymers, only crosslinked materials are
obtained. This is true even for pyrones ~inich is surprising
in view of the fact that bispyrones could be used to make
polymers from diethynyl comp~unds. Materials which I have
tried to react with polyacetylenes include: anthracene,
phenanthrene, 2,4-diphenyl furan, l,~-diphenylbutadiene,
1,6-diphenylbutatriene, hexachlorocyclopen~adiene, coumarin,
a-carboethoxypyrone, ~-carboethoxy ~-phenylpyrone, 2-pentyl-
3,4-dLphenylcyclopentadiene dimer~ 2-meth~ 3,4-diphenyl-
cyclopentadiene dimer. It will be noted that even ~icyclones
could Rot be used in place of the tetracyclones, even though
; -6-
: .
RD-5683
109~3~L2
in ~oth cases the dimer depolymerizes during heating to
the monomer.
Since the cyclization reaction by which my
polymers axe formed involves only one or both ethynylene
moieties of the butadiynylene groups, I can use any of
the solvent-soluble acetylenic polymers of the prior art.
Thus, for example, any of the acetylenic polymers
disclosed in the above-mentloned literature and patent
references will be found to be generally suitable for
conversion to the corresponding aromatized polymer by
reaction with tetracyclone. For example, Hay in his
U.S. patent 3,300,456, discloses polyacetylenes corresponding
to the formula,
H~ C- C-R-C--C ~ H
wherein n is an integer representing a number of
repeating units joined together to form a polymer
molecule and is at least two but usually represents a
value of at least 10 and is more probably at least 50
and the hydrogen atoms are on the terminal ethynylene
groups of the polymer molecule, and R is a divalent organic
; radical which can be an aliphatic or aromatic radical
wherein ~ne or more of the hydrogens of the aliphatic or
aromatic nucleus has been substituted by, for example,
O O O O
~, ~1 ,1 11 .
example, halogen, -OH, -OR, ~O-C-R, -C-OR, -C-R, -C-NEI2,
O O
Il ~I
-C-NHR, -C-NR2, -CN~ -SH, -SR, -SSH, -SSR, -SOR, -N02, -S02R,
-NH2, -NE~R, -NR2, etc. In all of the above ~or~lulas, R may
- 7 -
;;
RD-5683
be a monovalent organic radical such as defined above. From
a practical standpoint of being readily available at a
reasonable C08t, the polymers are general'y polymers of
diethynylalkanes or diethynylarenes~ preferably diethynyl-
benzenes, diethynylbiphenyls, bis(ethynylphenyl)ether, etc.
Hay, in his patent 3,3329916, discloses heteroatom
containing acetylenic polymers having the formula,
H f ~ H
- C-RI-C- C t M-C -C-R'~C _C ~ J
. . m
where M is a polyvalent radical selected from the group con-
sisting o~ -Hg-, ~,TlR-, ~Si(R)2, -Ge(R)2, -Sn(R)2, -Pb(R)2,
-PR, -~sR, -SbR, -BiR, -S~9 -Se-, -Te-, -Ni(AsR3)2,
2 , (S R3)2~ Pd~AsR3)2s -Pd(PR3)29 -Pd(SbR3)
~Pt(AsR3~2, -Pt(PR3)2 and -Pt(SbR3)2, where R is a monovalent
hydrocarbon radical, R' is a divalent hydrocarbon radical,
: 15 and n is a positive integer and is at leas one and m is a
positive integer and is at least two. Here again, from a
practical s~andpoint, R' is generally alkylene, preferably
lower alkylene or arylene, preferably phenylene.
The polyacetylenes disclosed by Hay in his patent
3,594,175 have one of the formulas
(a) H~ c~t~cH2o~ t-ocH2~ c 3c~ H
; m m n
-8-
-
~o~
RD-5683
where m is one of the integers O and l; n is an integer and
is at least 10 and R is selected from the group consisting
of arylene, including lower alkyl substi~uted arylene, halo-
arylene~ including lower alkyl substituted haloarylene, and,
5 in addition, when m is 0, alkylene and when m is 1, -Ri-X-R'~
where R~ is selected from the group consisting of phenylene,
halophenylene and lower alkyl substituted phenylene and X is
selected from the group consisting of -O-,
O R"
,.
-S- and -C-
O R"
where R" is selected from the group consisting of hydrogen
and lower alkyl,
(b) H-t-C --C~CH2~-R -OCH2-C -C-]- --H
where n has the value defined above and Ra is one of the
formulae,
_Rb_c_Rb_
and
.
RC ~,
' C-O
: ~ Rd
` 1043042 RD-5683
where Rb is arylene, R is arenyl, also called artriyl and R
is alkyl and aryl,
(c) copolymers having at least 10 repeating units having
both formulas (a~ and (b~; and
(d) copolymers having at least 10 repeating units having
: both formulas,
-O-CH2--C--~-- and
C----C~Rg~ C~
where Rf is as defined above for R when m is 1 and Rg is
alkylene or p-arylene.
51adkov et al. described polyacetylenes made from
dipropargyl ethers of dihydric phenols as well as poly- .
acetylenes prepared from dipropargyl esters of dicarboxylic
acids and dipropargyl acetals of aldehydes such as, for
example, benzaldehydesO Other suitable polyacetylenes are
those found in the scientific journals wherein other
investigators have prepared a wide variety nf polyacetylenes
based on the teachings of Hay. All such po~yacetylenes can
be used as starting material for preparing my polymers. In
addition, Hay in UDS. patent 39519,611 describes modified
polyacetylenes obtained by reacting a polyacetylene with N
arylsydnones to introduce pyrazole units in ~he polymer
backboneO Such modified polymers still con~aining some un-
reacted butadiynylene groups likewise can be used as the
polyacetylene for making my polymersO
-10-
RD-5683
Of all of the above polyacetylenes, the most readi-
ly available are those from diethynylhydrocarbons and di-
propargyl ethers of dihydric phenols. In order to have the
highest carbon content, the polymers shou d be made from di-
ethynyl arenes, the most readily available ones being
- diethynylbenzenes. To increase ~he solubility of the poly
mers of the latter in solvents, the isomers can be
copolymeriz~d together or still further increased by co-
polymerizing with the dipropargyl ethers. A particularly
good one whlch is effective in low concentrations is the
dipropargyl ether of 4,4'-isopropylidened~phenol (Bisphenol
A), also called 4,4'-isopropylidenebis(propargyloxybenzene).
:
For many applications, I prefer to use as my starting poly-
acetylene, the copolymer obtained by oxidatively coupling a
mixture of m-dLethynylbenzene, p-diethynylbenzene and 4,4'-
isopropylidenebis (propargyloxybenzene), specially those
having, on a weight basis, 1-25% p-diethynylbenzene, 60-99a/o
m-diethynylbenzene and 0-35% 4,4'-isopropylidenebis(propargyl-
oxybenzene), i e., R in the formulae of the repeatin~ units
of the polymer are 1-2S% p-phenylene, 60-99% m-phenylene and
CH
0 35% -CH2 0 ~ ~ O-CH2-
Alt~ough I can use any of the tetracyclones, the
,
most readily available tetracyclones are those having the
formula 3
~4~42 RD-5683
o
"
"C~
Il "
- R"-C - ~-R"
where each R', independently, :is lower alkyl, lower alkoxy-
carbonyl, phenyl or halophenyl and each R", independently, is
phenyl or halophenyl. Typical of the substituents which R'
can be, are methyl, ethyl, propyl, isopropyl, the various
butyl isomers, i.e., n-butyl, isobutyl, cyclobutyl, t-butyl,
the varioas pentyl isomers, the various hexyl isomers, the
various heptyl isomers, the various octyl isomers, etc., the
0.
lower alkoxycarbonyl, i.e.; R'OC-, where R' is~lower alkyl,
~10 examples of which are given above, or phenyl or halophenyl,
i.e., phenyl in which from 1 to 5~ preferably 1 to 2 of the
hydrogen atoms have been replaced by halogen, preferably
chlorine. R" is phenyl or halophenyl, examples of which have
been given above.
~15 Those tetracyclones where each R' independently is
lower alkoxycar~onyl are new chemical co~poundsO ~hey are
readily prepared by first reacting benzil or the appropriate
halobenzil with the appropriate lower dialkyl ester o~ 3-
oxoglutaric acid, sometimes called acetone dicarboxylic acid,
in the pre~ence of a dilute alkali metal hydroxide solution
-
in an alkanol~ generally methanol, to pro~duce a par~ially
dehydrated intermediate which is then dehydrated to the
'
-12-
-
. ,
104304Z RD-5683
tetracyclone. The reaction proceeds readily at room
temperature where it is generally run, but may be hastened
by heating if desired. The progress of the reaction is
easily followed by monitoring the disappearance of the
benzil from the reaction medium. The partially dehydrated
intermediate is ~urther dehydrated with an anhydride, for
example, acetic anhydride in the presence o a small amount
of sulfuric acidO These reactions are shown in the following
equations where each Ra independently is lower alkyl and each
Rb individually is phenyl or halophenylS
O O O 0 0 alkali metal
R O-C-cH2-c-cH2-c-~Ra + Rb b ~ H20
lower dialkylbenzil or
3-oxoglutaratehalobenzil
O
O " O
" jC ~ " __ dehvdratine
R -O-C-C CH~C-ORa agent
b- C~, Rb
OH
4-hydroxy-2,5-bis(lower alkoxycarbonyl)-3,4-di(phenyl or
- halophenyl)-2-cyclopentene
o
O " O
.t ~C~ "
-- R O-C-C C-C-OR
a " " a
- Rb~C ~ Rb
2,5-bis(lower alkoxycarbonyl)-3,4-di-(phenyl or halophenyl)-
cyclopentadienone
These te~racyclones react with ~)ne of the ethynylene
moieties of the butadiynylene groups found in the poly-
-
~ -13-
~ ! '
:~ ~
104304z RD-5683
acetylenes according to the following scheme:
O
Rl-C~ `C-R
,. ,.
~ ~ -C--C-C--C- ~ R2-C---C-R - - >
-C =C-C_C- .~
1 C ~ ~C-Rl ~ CO
R2 R2
The reaction is carried out at elevated temperatures under an
~5 inert atmosphere using a solvent in which the polyacetylene
is soluble or at least becomes somewhat soluble at temperatures
in the range of 50 to 130C. in the presence of a free-
radical scavenger, e.g., a phenol such as a 2,4,6-trisubsti-
tuted phenol. ~Haloarenes and haloarene ethers especially
chloroarenes~and chloroarene ethers or mixtures thereof, for
example,-chlorobenzenes, chlorobiphenyls, chlorodiphenyl
: ethers, etc., are excellent solvents for carrying out this
reaction. The reactîon is carried out, generally using the
~ lowest temperature at which the reaction proceeds at a
reasonable rate which is easily monitored by noting the
evolution of carbon monoxide~
In the presence of sufficient tetracyclone, reaction
~- between one ethynylene moiety of the butadiyny~ne group and
the tetracyclone proceeds readily to com~letion ~or every
butadiynylene group o~ the polymer and the polymer repeating
, .
. . ~ . . ~
.~ -14- ~
~ ' ~
l043~æ
RD-5683
unit are those having formula ~b). Since it is the
conjugated triple bonds of the butadiynylene groups which
render ~he polymers thermally unstable~ the thermostability
increases as the degree of this reaction increasesO Like-
wise, the solubility of the polymer, especially noticeable ifi~ is initially only very slightly solubl3 increases as the
degree of reaction increases. The temperature necessary to
cause this reaction is lowest for 2,5-dialkyl-3,4-diaryl-
cyclones, generally in the range of 130-150C. and is highest,
generally in the range of 225-240C. for the 2,3,4,5-tetra-
arylcyclones with the 2,5-di(lower alkoxycarbonyl)-3,4-
,
diarylcyclones requiring intermediate temperatures, generally
in the range of 18Q-200C. The best temperature to use for
cyclizing any particular polyacetylene with any particular
tetracyclone i5 readily determined by rapi~ly heating the
reaction mixture and using that temperature at which a
controlled rate of evolution of the carbon monoxide is
obtained.
The second ethynylene moiety of the original buta-
diynylene groups of the polymer can also be reacted with the
same or different tetracyclone by heating under the same
general conditions above but to a higher temperature than
that required for the first reaction for that particular
; tetracyclone. The reaction does not proceed ~o completion
;~ 25 apparen~ly because of the steric effects of the neighboring
-15- ~
10~3042 RD-5683
adducts. Highest yields in the second reaction are obtained
when a tetraarylcyclone is used in which case about 60% of
the remaining ethynylene groups (80% of the total) can be
reacted wlth the tetraarylcyclones. Where both ethynylene
moieties of the butadiynylene group are reacted, the repeat-
ing unit of the polymer has formula (c).
It is obvious that one t~tracyclone can be used for
the first reaction and a second tetracyclone used for the
second reaction~ In this case, since the tetraarylcyclones
give the highest yield in the second reaction~ if one wanted
.
to use a 2,5-dialkyl-394-diarylcyclone or a 255 di(alkoxy-
- .
carbonyl)-3,4~diarylcyclone in conjunc~ion with a tetraaryl-
cyclone, the latter, preferably would be used for the second
reaction. Although solubility and polymer stability are not
generally increased with the degree of this seeond reaction,
oxidative stability at elevated temperatures below the
thermal decom~osition point are improvedO
Solutions of the polymers obtained by either re-
action are readily cast into films. These solutions also can
be used to coat fibers, cloths, papers or mats of carbon or
- other high impregnate carbon in order to permit the coated
; article~to be molded under heat and pressure into composites
or laminates~
.:
In order that those skilled in the art may better
~- 25 understand my invention, the following examples are given by
-16_
:
1~43042 RD-5683
way of illustration and not by way of limi~ation. In all
the examples parts are by weight and temperatures are in
degrees cen~igrade unless otherwise stated. Where eIemental
analyses are given, the determined values are followed by the
theoretical values in parentheses, In Examples 5 and 6, the
tetracyclone exists as the dimer at room temperature, but
readily dissociates during heating to the reaction temperature.
- EXAMPLE 1
A mixture of 0.5 g. of a polyacetylene made by
oxidatively coupling a mixture of 90% m-diethynylbenzene and
10% ~-diethynylbenzene, 0.02 g. of 2,6-dioctadecyl-4-methyl-
phenol, 5 g~ of 2,3,4,5 tetraphenylcyclopentadiene and 5 ml.
of a mixture of chlorinated biphenyls having 32% chlorine
was heated to~300 under a nitrogen atmosphere for 6 hours
in a liqoid metal bath. At the end of this time, an
~- addi.tional 5 ml. of the chlorinated biphenyl mixture was
added to cool the reaction mixture quickly to about 200
~ and to aid in the removal of the solution from reaction
- vessel. The solution was added dropwise to 250 ml of
methanol wLth stirring. After washing with additional
~` methanol to remove unreacted tetracyclone and drying, the
-~ polymer weighed 2.83 g. The infrared and nmr spectra were
.
consistent with a polymer structure some of~whose repeating
units contained 1 cyclized structure and the other units
~.
contained 2 such structures. Based on the yield of polymer,
each one of the butadiynylene groups of the polymer has
,
17-
.
1043(~42 RD-5683
reacted with the tetracyclone to form at least one 3,4,5,6-
tetraphenyl-1~2-phenylene ring of which 52% had formed 2
such ringsO This polymer therefore contained repeating units,
38% having formula (b) and 62% having formula (c), where R is
m-phenylene or ~-phenylene and each R' an~ Rl' is phenyl~
EXAMPLE 2
When the above reaction was repeated but using a
temperature of 225, the yield was l.9 grams showing that all
of the butadiynylene groups had reacted with the tetracyclone
but that only one of the ethnylene moieties bf the buta-
diynylene group had been cyclized~ The presence of the
remaining ethynylene group was established by measuring the
13C nmr spectrum.
:
EXAMPLE 3
When Example 1 was repsated but the heating was
initiated at ~10 and over a period of 40 minutes raised to
292 and maintained a temperature of 292-298 for 80 minutes,
the product contained 81% (b~ units and l~V/o (c) units as
defined in Escample 1.
The polymers described above are soluble at 25 in
common organlc solvents as benzene, chlorinated aromatic
liquids, chloroform and tetrachloroethane. Clear, coherent
films can be cast from the solutions. MelCing point ranges
on a hot-stage microscope vary with extent of reaction: for
-18- ,
. .
lb 4 3~L2 RD-5683
100~/o (b) units, 338-350; for 81% (b) units - 19% (c) units,
352-375C.; for 38% (b) units - 62% (c~ units: 360-375C.
When polymers with only (b) units were heated in air at
10C./minO weight losses did not occur until approximately
430, in a nitrogen atmosphere the sample began~to lose weight
at 460C.
EXAMPLE 4
When Example 1 was repeated but using a polyacetylene
obtained by oxidatively coupling a mixture of 82% m-diethynyl-
benzene, 8% ~-diethynylbenzene and 10% 4,4'-isopropylidene
bis(proFargyloxybenzene) 9 the dipropargyl ether of 4,4'-
isopropylidenediphenolO In one case~ a high molecular weight
polymer was used and in another case a polymer in which suffi-
cient phenylacetylene was used as a chain stopper to obtain
- 15 a low molecular weight polymer having an average degree of
polymerization of 10. In these reactions, 5 ml. of benzene
was used in place of ~he chlorinated biphenyl as solvent which,
although i~ evaporated during the heating of the reaction
mixture9 did~provide an initial liquid phase for the reaction
mixture which was maintained even after the evaporation of
the benzene. No chlorinated biphenyl was add~d after the
reaction period, so that on cooling a solid ma~ss resulted.
This was worke;d up with acetone but due to the extreme
solubility of the resulting polymers, especially that from
.
` -19-
: ~43~42 RD-5683
the low molecular weight initial polymer, even in methanol,
it was impossible to recover all of the resulting polymer.
Based on the amount of recovered polymer, at least 44% of the
repeating units of the resulting polymer of the initially low
molecular weight polymer had been converted to (b) units and
in the case of the higher molecular weight product, 49% of
the repeating units.
EXA~LE 5
.... _ .
A mixture of 2.48 g. of the polyacetylene of
Example l, 5.72 g. of 2~5-dimethyl-3J4-diphenylcyclopenta
dienone, 0,05 g. of 236-dioctadecyl-4-methylphenol and 40 ml
of chlorobenzene were heated at 130, the reflux temperature
of the reaction mixture, for a period of two hours under a
nitrogen atmosphere~ The reaction mixture was added drop-
wise to 450 mL. of acetone, the precipitate separated by
filtration, washed and dried to yield 6.72 grams of product.
~ Based on this yield, one of the ethynylene moieties of each
; butadiynylene group of the initial polymer had been
converted to 3,6~dimethyl-4,5-diphenyl-192-phenylene groups,
i,e., all of the repeating units of the ~olymer corresponds
to formula (b) where each R' is methyl, each R" is phenyl and
R is m-phenylene or ~phen~lene.
EXAMPLE 6
A mixture of 0.25 g. of the polyacetylene of
-20~
~ - RD-5683
Example 1, 1.69 g. of ~ me~ yl-3,4-diphenylcyclopenla-
dienone9 0,01 gu of 2,6-dioctadecyl-4-methylphenol and 2.5
ml. of a chlorinated biphenyl having a chlorine content of
32% was heated at 225 under nitrogen atmosphere for one hour.
An additional 5 ml. of the chlorinated biphenyl was added
and the reaction mixture precipitated by adding to 500 ml. of
acetone. After filtering and drying the precipitate, a yield
of 0.85 g. of polymer was obtained. Based on this yield,
each repeating unit of the polymer had at least one 1,2-
phenylene group on the backbone and of these 30% had ~wo such
unitsg i~e., 70% of the repeatlng units had-formula (b) and
,
30~/O had formula (c) where each R' is methyl and each Rl' is
phenyl and each R is m-phenylene or ~phenylene.
EXAMPLE 7
- 15 Using a polymer similar to that prepared in Example
; 5 but having only 0.8 of its repeating units cyclized to
units corresponding to formula (b) where each R' is methyl and
each R" is phenyl and R is m-phenylene or ~-phenylene,
further cyclization was carried out as follows: A mixture of
0.71 g. of this polymer, 1,54 g. of 2,3,4,5-tetraphenylcyclo-
pentadienohe~ 0.02 g. of 2,6-octadecyl-4-methylphenot and 5
ml. of a chlorinated biphenyl having a chlorine content of
32% was heated under nitrogen at 300 for 30 minutes. Upon
cooling, a precipitate started to form and acetone was added
to complete the precipitation. The polymer was filtered off~
? 21
~ 04304Z RD-5683
dried and redissolved in 15 ml. of chlorobenzene and again
precipitated by pouring into acetone. After filtering, wash-
- ing and drying, a yield of 0.9 g. of product was obtained.
The nmr spectrum of this polymer indicated that 60% of the
remainLng ethynylene moieties had been cyclized to 1,2-
phenylene gro~ps, i.e., 60% of the repeating units of the
polymer had formula (b) and 40% of the repeating units had
formula (c) where each R' is methyl or phenyl, each R" is
phenyl and each R is m-phenylene or p-phenylene
EXAMPLE 8
.,
This example is a typical preparation to be used in
.
preparing 2,5-bis(lower-alkoxycarbonyl)-3~4-diarylcyclopenta-
dienones. A solution of 34.8 g. of dimethyI 3-oxoglutarate,
21.0 g. of benzil in a 0.5% potassium hydroxide solution in
250 ml. of methanol was allowed to stànd under a nitrogen
atmosphere with stirrlng at room temperature After one hour,
the solution had become clear. After 20 hours, a precipitate
had formed in the reaction mixture and a sample o~ the liquid
phase showed that no benzil was present. The reaction mixture
was poured into 500 ml. of water to precipitate all the
product. After filtration9 washing and drying, there was
obtained 28.82 g. of 4-hydroxy-2,5-bis(methoxycarbonyl)-3,4-
diphenyl-2-cyclopentenone. After recrystallization from 200
mlO of benzerle, elemental analysis showed: C, 69.5 (68.9);
:
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.
.
.
RD-5683
H, 4.9 (4.92). The compound was further identified by its
nmr spectrum.
The above intermediate was further dehydrated to
the desired tetracyclone by dissolving 22.01 g. of the above
intermediate in 40 g. of acetic anhydride to which 3 drops of
concentrated sulfuric acid were added. The reaction mixture
was heated to obtain a homogeneous solution and allowed to
stir 1/2 hour after removal of thP source of heat. The
reaction mixture wa~ poured to 450 ml. of water, causing the
desired 295-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone
to precipitate as crystals which after filtering, washing and
- drying in a vacuum at 50, weighed 20.57 g. After
recrystallization from acetic acid~ the product had a melting
point of 162-164C, The product was identified by its nmr
,
~ 15 and infrared spectra.
,
Elemental analysis is shown: C, 72.2 (72041); H,
4.7 (4.6). Mass spectrum showed the parent peak, m/e 348.
EXAMPLE 9 ~ ~
A mixture of 0~62 g~ of the polyacetylene of Example
l, 2.68 g. of the tetracyclone of Example 8, 0.02 g. of 2,6-
octadecyl-4-methylphenol and 10 ml~ of o-dichlorobenzene was
heated at 180, the reflux temperature o the re~ction
mixture, under a nitrogen atmosphere for 2 hours. After
cooling, the reaction mixture was added dropwise to a 50-50
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~3~42 RD-5683
methanol acetone mixture and the precipita~e washed with
additional acetone and methanol. After drying there was ob-
tained 1.85 g~ of polymer. Based on this yield, 80~/o of~the
butadiynylene groups of the original polymer had been
5 converted to repeating units having the formula (b), the
balance being formula (a) where each R' is methoxycarbonyl,
each R" i5 phenyl and each R is m-phenylene or p-phenyleneO
EXAMPLE 10
~ .
A mixture of 2 . 22 gO of a polyacetylene made by
oxidatively-c~upling m-diethynylbenzene, 6.96 g. of the cyclone
of ExampIe 8, 0.1 g. of 2,6-octadecyl-4-methylphenol and 60
mlO of a chlorinated biphenyl having 32% chlorine was hea~ed
under a ni~rogen atmosphere at 185 for 2 hours. The reaction
mix~ure was poured into a mixture of 700 ml. of methanol and
700 ml. of ac~tone~ The product was filtered, washed and
dried - yield 4. 0 g. Based on this yield, 90% of ~he initial
butadiynylene groups had ~een cyclized so that 90~tO of the
repeating units had formula (b), the balance being formula
(a) where eàch R' is methoxycarbonyl, each R" is phenyl and
each R~is m-phenylene.
All of the polymers from the above examples are
readily soluble to at least 10% at room temperature in such
commonly available solvents as ^hloroform~ tetrachloroethane,
benzene, chlarobenzene and nitrobenzene and can be cast into
clear flexible films. These films are thermally stable with
~24-
~43~æ RD-5683
the thermostability increasing in the order from those whose
R' groups are methoxycarbonyl to t:hose whose R' groups are
methyl to those whose Rl groups are phenyl. Incipient de-
composition does not begin in nitrogen or air below 360 for
; 5 any of the polymers and goes as high as 46~ in nitrogen.
When heated in nitrogen at 900, weight loss increa~es in the
order of those polymers where the R' groups are methyl (27%)
to those where the R' groups are phenyl (31%) to those where
the R' groups are methoxycarbonyl (34%)~ In the case where
the R' groups are phenyl, io e.~ both R' and R" groups are
phenyl, the weight loss is in close agreement for that which
would be.expected if all of the phenyl groups in the 3 and 6
positions were cleaved from the 1~2-phenylene rings.
`
Solutions of the polymers in addition to being able
to be cast into films readily coat the surface of carbon
fibers and:~can be used to impregnate the tows of such fibers
to produce.prepregs which can be aligned and molded to pro-
doce high performance composites. Best physical properties
are obtained from those cycllzed polymers where both the R'
and R'i groups are-phenylO
. Those cyclized polymers where the R' groups are
methoxycarbonyl can be hydrolyzed so that the alkoxycarbonyl
groups are converted to carboxyl groups to produce polymers
having ion exchange properties~ If desired, the ester groups
can be converted to amide groups.
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: : .
10 4 3~ ~ 2 RD-568
In addition to increasing the thermostability and
solubility, the polymers of this invention likewise have
softening points which increase with the degree of reaction.
Although the examples have illustrated how to attain a high
degree of cyclization, a lower degree of cyclization is at-
tained either by using 3 shorter reaction time or a
deficlency of the tetracycloneO However, ~hen the latter
technique is used, the reaction rate is slower and gelation
due to thermal instability of the polymer ean occur, especial-
ly if the tetraarylcyclones are used which require generallyhigher reaction temperatures than the other tetracyclones.
In those cases where I have attained a low degree of cycli-
zation, a noticeable improvement in stability and solubility
is attained when as low as 15% of the butadiynylene groups
have been cyclized to contain at least one cyclic structure~
i.e., no more than 85% of the repeating units have formula
(a).
Although the above examples have illustrated many
modifications of my invention, obviously, other modi~ications
and variations of the present invention are possible in light
of the above teachings. Tt is, therefore, to be understood
that changes may be made in the particular embodiments of
the invention described which are within the full intended
scope of the invention as defined by the appended claims.
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