Note: Descriptions are shown in the official language in which they were submitted.
~L~.235i37
BACKG~O~.~D OF ~HE IN~ENTION
(a) Statement of the Invention
The present invention relates to polymerizable macro-
molecular monomers and chemically joined, phase separated thermo-
plastic graft copolymers.
(b) Description of the Prior Art
Polymer technology has developed to a high degree of
sophistication and extensive research efforts in this direction
are being undertaken to obtain improvemen-ts in polymer proper-
ties. Some of these efforts lead to polymer materials capable
of competing with metals and ceramics in engineering applica-
`` tions,~
Attempts have been made to blend two different types
of polymers in order to obtain the desired properties of each
.: ~
polymer component in the blend, but these attempts have general-
~; 20 ly been unsuccessful due to incompatihility. Despite the
general acceptance of the fact of incompatibility of polymer
pairs, there is much interest in devising means whereby the
` advantageous properties of combinations o~ polymers may be
combined into one product.
' ` - ' '
'
: ` '
~ .
~ -2-
22234
~.2~
One way in which this ob~ective has been sought
involves the preparation of block or graft copolymers. In
this way, two different polymeric sesments, normally incompatible
with one another, are joined together chemically to give a
sort of forced compatibility. In such a copolymer, each polymer
segment continue~ to manifest its independent polymer properties.
. . . . , ,.. ~, ,
~hus, the block or graft copolymer in ma~y instances possesses
a combination of properties not normally foun~ in a homopolymer
or a random copolymer.
U.S. Patent No. 3,235,626 to Waack, assigned to
Dow Chemical Company, describes a method for preparing graft
copolymers of controlled branch configuration. It ls described
that graft copoLymers are produced by irst preparing a
prepolymer by reacting a vinyl metal compound with an olefinic
monomer to obtain a vinyl terminated prepolymer. A~ter
protonation and catalyst removal, the prepolymer is dissolve~ -
in an inert solvent with a polymerization catalyst and the
prepolymer is thereafter reacted wi~h either a different polymer
having a reactive vinyl ~roup or a different vinyl monomer
under free-radical conditions.
.
The limitations on the preparation of these co~
polymers axe mechanistic. Thus, there is no means for controll-
ing the spacing of the sidechains along the backbone chain and
~he possibility of the sidechains having irregular sizes. Due
to the mechanistic limitations of the prior art methods, i.e.,
the use of an alpha-olefin terminated prepolymer with acrylo-
.~
nitrlle or an acrylate monomer under free-radical cond tions,
complicated mixtures of lree homopolymers result.
In view of the above considerationsf it would be
hiighly desirable to devise a me~ns for preparing yraft co-
polymers wherein the production of- complicated mi~:tures o
--3--
~2234
~`.Z3~
free homopolymers is minimized and the beneficial properties
of the sidechain and backbone polymer are combined in one
product.
It is recognized and documented in the literature,
such as R. Waack et al; Poly~er, Vol. 2, pp~ 365-366 (1961),
and P. Waack et al, J. ~. Chem., Vol. 32, pp. 3395-3399
(1967), that vinyl lithium is one of the slawest anionic polymer-
ization initiators. The slow initiator characteristic of vinyl
lithium when used to polymerize styrene produces a polymer
having a broad molecular weight distribution due to the ratio
of the overall rat:e of propagation of the styryl anion to
that of the vinyl lithium initiation. Accordingly, following
the practice of U.S. Patent No. 3,235,626, a graft copolymer
having sidachains of uni~orm molecular weight cannot be pre-
pared.
U.S. Patent Nos. 3,:390,206 and 3,514,500 describe
processes for terminating free-radical and ionic polymeri~ed
polymers with unctional groups which are described as capable
of copolymerizing with polymerizable monomers. The unction-
ally texminated prepolymers described by these patentees
wou~d be expected to have a broad molecular weight dis*ri-
bution and, therefore, would not be expected to develop
~- ultimate physical properties which are found in polymers
formed from prepolymers having narrow molecular weight
distribution.
U.S Patent No. 3,786,116 to Milkovich and Chiang,
.
granted on January 15, 1974 (which is assigned to the same
assignees as the present application~
descrlbes phase sepax~ted
~;
--4--
2223
~.23~
thermoplastic graft copolymers derived from ethylenically un-
saturated monomers as the bac~bone comonomer, and as side
chains, copolymerized macromolecular monomers having sub-
stantially uniform molecular weight distribution formed from
anionically polymerized monomers.
U.S. Patent No. 3,842,146 to Milkovich and Chiang,
granted on October lS, 1974, whish is also assigned to the
same assignee as the present application
discloses and claims polymerizable
di-block macromolecular monomexs of a polymerized mono-
alkenyl-substituted aromatic hydrocarbon and a polymerized
conjuyated diene and having a polymerizable end group. The
polymerizable di-block macromolecular monomers have a sub- -
stantially uniform molecular weight distribution. Copolymers o~
lS such macromolecular monomers with backbone-forming gra~t co-
polymerizing monomers are disclos~d and claimed in U.S. Patent
No. 3,862,263, granted January 21, 1975, of Milkovich,
~` Chiang and Schulz,,
.
- 20 These polymerizable macromolecular monomers and
; graft copolymers overcome many of the aforementioned di~-
advan'ages of prior art compositions.
It is a particular object of the present invention
to effect even ~urther improvement over the polymeric com-
positions o the prior art.
.: .'~ .
: ~ SUMMARY OF THE I~IVE:NTION
The present invention relates to polymerizable
"tapexed" (or "graded") bloc~ macromoleculaL monomers having
a substantially uniform moleculax ~eight distribution such
-5-
~0 22~34
.
` '" ~" ' '
that their ratio of Mw/Mn is less than akout 1.1, where Mn is
the number average molecular weight of the polymerizable
monomers, said polymerizable monomers being characterized by
the formula:
I - A - B - C - A' - X
wherein "I" is the residue of an anionic initiator, "A" and "A"'
are each a polymeri~ed mono-alkenyl-substituted aromatic hydro-
carbon, "B" is a polymer of a conjugated diene, "C" is a tapered
or graded copolymer of a mono-alkenyl-substituted aromatic
hydrocarbon and a conjugated diene, and "X" is a polymerizable
end group containing either a vinyl moiety, a vinylene moiety,
a glycol moiety, an epoxy moiety, or a thioepoxy moiety.
The macromolecular monomers o~ ~he present invention
are made ~y anionic polymerization employing an active anionic
initiator such as sec.-butyl lithium in an anhydrous solvent
sucn a~ benzene. A termi3lal b oc.~ of polymarized mono-
alkenyl-substituted aromatic hydrocarbon, preferably polystyrene
designated as the group 'IA" lS irst formed by addins mono-
- meric styrene. Af~er the styrene is polymerized, there is
2~ added a mixture in desired molecular ratio of a mono-alkenyl-
substituted arolltatic hydrocarbon and a conjugated diene such as
butadiene or isoprene. The polymerization immediately
commences again because of the presence of the living polymer.
Due to the substanti lly higher reactivity of the diene, how-
~5 ever, it polymerizes first in preference to the mono-alkeryl-
substituted aromatic hy~rocarbon, thereby ~orming the block
designate~ as "B". A~ter a sukstantial amount of the dlene is
polymerized, its concentration becomes signi~icantly depleted
~nd at tne relatively higher concentr~tions o~ ti~e l~.ono-
~0 al~enyl-substituted aromatic hydrocarbon, it begins to co-
polymerize with the diene. There is ormed, therefore, ~ at
~ %3~
is termed a graded or tapered block designated as "C" which
at first contains a relatively high proportion of the diene,
but as the latter is used up, gradually becomes higher and
higher in the proportion of the mono-alkenyl-substituted
aromatic hydrocarbon, until at the other end of the graded
block it approaches substantially all of the latter, thereby
forming the group designated as "A".
The tapered blocX macromolecular monomer of the
present invention has been found to provide valuable aid
in the graft copolymerization with the backbone-forming co-
monomers. Thus, in some systems for the graft copolymerization
of macromolecular monomers of the diblock type referred to
abovet especially in suspension polymeriza-tion, the suspension
droplet becomes a poor solvent for the macromolecular monomers
; 15 or diblock monomer r resulting in low conversions of macro-
molecular monomer, or in other words low levels of incorporation
of the macromolecular monomer into the graft copolymer. This
behaviour was found to be prevalent when attempting to graf~
copolymerize styrene dlblock macromolecular monomer where no
~ 20 co-solvent was used. In other instances, when the styrene
; level in the droplet was reduced to a low level due to con-
sumption of the styrene in the graft copolymerization, the
. end of the molecule having the reactive group is non-solvated
and thus cannot react read1ly with a comonomer. By using tne
`~ 25 tapered block macromolecular monomers of the present invention,
~: however, the end of the macromolecular chain, having a
functional group such as styrene or other mono-alXenyl-substituted
aromtic hydrocarbons, thereby increases the solvency of the
~ functional group on the macromolecular monomers when using an
- 30 aromatic comonomer such as styrene and thereby enhances theincorporation of these types of macromolecular monomers into
the backbone of the graft copolymer to a much greater degree.
22234
3~
Furthermore, the tapered block macromolecular monomers
of the present invention enable one to obtain a much broader
range of glass transition temperatures (Tg's), as explained
more fully hereinafter, if one desires to have such physical
properties.
The polymerizable tapered or graded block macromolecular
monomers will generally have a molecular w.eight in the range of
from about 5,000 to about S0,000. Preferably, the polymerized
.mono-alkenyl-substituted aromatic hydrocarbon "A" portion of the
polymerizable monomers will have a molecular weight in the range
of from 2,000 to about 25,000, and the portion designated as
"R-C~A"', which includes the tapered or graded block copolymer
"C" portion of the polymerizable monomer will have a molecular
weight in the range of from about 1,500 to about 48,000.
The preferred mono-alkenyl-substituted aromatic hydro-
carbon for the formation o the groups designated as "A" and "A"'
is styrene, but alpha-methyl styrene is also contemplated. More-
over, mixtures of styrene and alpha-methyl styrene may be used
for the ~orma~ion of the groups "~", "C" and "A'", in which
case the different reactivities of these t~o monomers produces a
further degree of tapering or grading of the blocks"A", "C" and
"A"', leading to interesting and desirable properties and
bellavior in the polymerization process and the final products.
The present invention also relates to thermoplastic
graft copolymers comprised of copolymeric backbones containing
.
~
~" 22234
3~3~
a plurality of uninterrupted repeating units of the backbone
polymer and at least one integrally copolymerized moiety per
backbone polymer chain having chemically bonded thereto a
- substantially linear polymer which ~orms a copolymerized side
chain to the backbone, wherein each of the polymeric side
chains has substantially the ~ame molecular weight and each
polymeric side chain is chemically bonded to~ only one back-
bone polymer. Each of said linear polymer side chains is formed
from a high molecular weight polymerizable (or macromolecular)
monomer comprising at least one polymeric segment having at
least about 20 uninterxupted recurring monomeric units of
at least one anionically polymerized compound ~hich is a
mono alkenyl-substituted aromatic hydrocarbon, said macro-
molecular monomer also comprising a copolymerized segment
of a mono-alkenyl-substituted aromatic hydrocarbon and a
conjugated diene. Each of said macromo1ecular monomers
`' texmina~es with no more than one polymerizable end group
containiny a moiety selected from vinyl, vinylene, glycol,
: . .
~` epoxy, or thioepoxy groups per mole of said macromolecular
monomers which is the aforesaid integrally copolym2rlzed
moiety. Said macromolecular monomers are characterized as
having a substantially uniform molecular weight distribution
~, :
; such that their ratio of Mw/~l is less than about l.l, ~here
Mw is`the weight average molecular weight o~ the macro-
molecular monomers and Mn is tl~e number average molecuiar
weight of the macromolecular monomers. Said macromolecular
monomers are further denoted as capable o~ copolymerizing
with a second polymeri~able compound having a relatively low
molecular weight to obtain said copolymeric backbone, which
is a cllemically joined, phase separated thermoplastic graft
_g _
,
~.23537 22234
copolymer, said copolymerization occurring through said polymer-
izable end group, said polymerizable end group thereby occurr-
ing as an integral part of the backbone of said chemically
joined, phase separated thermoplastic graft copolymer.
The graft copolymers of the present invention assume
a "T" type structure when only one side chain is copolymerized
into the copolymeric backbone. However, when more than one
side chain is copolymerized into the bac~bone polymer, the
graft copolymer may be characterized as having a comb-type
structure illustrated in the following manner:
c-c-c-b-c-c-c-b-c-c-c-b-c-c-c
., . I I I
a a a
I
a a a
a a a
wherein "a" represents a substantiaily linear, uniform molecular
weight polymer or copolymer having a sufficient molecular weight
such that the physical properties of at least one of the sub-
- ~ stantially~linear polymers are manifest and having the other
previously mentioned characteristics descrlbed hereinaft2r in
more detail; "b" represents a reacted and polymerized end
group chemically bonded to the side chain, "a", which is
~; integrally polymerized into the backbone polymer, and "c'l is
the backbone polymer having uninterrupted segments of sufficient
molecular weight such that the physical properties of the
polymer are maniest.
The bac~bone of the graft copolymers o~ the present
invention preferably contains at least about 20 uninterrupted
~ecurring monomeric units in each segment. It has been Eound
that ~his condition pro~ides the graft copolymer the properties
of the pol~mer. In other ~ords, the presence of segments
--10--
.
22234
containing at least about 20 uninterrupted recorring monomeric
units provides the graft copolymers with the physical properties
attributed to this polymer, such as crystalline melting point (Tm)
and structural integrity.
S The bacXbone polymeric segments of the chemically joined,
; phase separated thermoplastic graft copolymers of the present
invention are derived from copolymerizable monomers, preferably
the low molecular weight monomers. A par~icularly preferred
group of copolymerizable monomers includes the non-polar or
ethylenically-unsaturated monomers, especially the monomeric
vinylidene type compounds, i.e., monomers containing at least
one vinylidene CH2 = C - group. The vinyl type compounds
H
represented by the formula CH2 = C - wherein a hydrogen is attach-
ed to one of the free valences of the vin~ylidene group are con-
templated as falling within the generic scope of tne vinylidene
;~ compounds referled to hereinabove.
The backbone polymers of the present inven~ion are also
comprised of polyolefins which include polymers of alpha-olefins
of the formula:
CH2 = CHR
wherein R is either hydrogen, or an al~yl or aryl radical contain-
~ ing 1 to about 16 carbon atoms, and include ethylene, propylene,
- butene-l, pentene-l, hexene-l, styrene, etc.; copolymers of
~ -olefins including the ethylene-propylene copolymers; and
poLymers of polymerizable dienes including butadiene, isoprene,
etc~ -
'11- .
~ 353~
Thus, in accordance with the present teachings, a
chemically joined, phase separated thermoplastic graft
copolymer is provided of:
(1) from about 1% to about 95% by weight of a
copolymerizable tapered block macromolecular monomer of the
formula:
I - A - ~ - C - A' - X
: wherein "I" is the residue of an anionic initiator, "A" and
'1A'" are each a polymerized mono-alkenyl-substituted aromatic
:. 10 hydrocarbon, "B" is a polymer of a conjugated diene, "C" is
a tapered copolymer of a mono-alkenyl--substituted aromatic
hydrocarbon and a conjugated diene, "X'l is a copolymerizable
end group, the tapered block macromolecular monomer has a
: molecular weight in the range of from about 5,000 to about
50,000 and has a substantially uniform molecular weight dis-
tr:ibution such that its ratio of Mw/Mn is less than about
; 1.1, the tapered bloek maeromolecular monomer is furthercharacterized as having no more than one copolymerizable
end group on the terminal portion per linear macromolecular ~:
monomer chain, copolymerized with
: (2) from about 99% to about 5% by weight of a
copolymerizable comonomer forming the polymeric backbone of
the graft copolymer and the copolymerizable tapered block
macromolecular monomer forming linear polymeric side chains
of the graft copolymer, wherein:
(a) the polymeric backbone of the graft copolymer
is eomprised of polymerized units of the eopolymerizable
,;
- eomonomer, the eopolymerizable comonomer is at least one
ethylenically-unsatuxated monomer and mixtures thereof,
(b) the linear polymerie side chains of the graft
copolymer are comprised of the copolymerized tapered block
-lla-
~1 . .
3S37
macromolecular monomers, the copolymerization occuring be-
tween the copolymerizable end groups of the macromolecular
monomer and the copolymerizable comonomer; and
(c) the linear polymeric side chains of the graft
copolymer which are copolymerized into the copolymeric back-
bones are separated by at least about 20 uninterrupted recurr-
ing monomeric units of the backbone polymer, the distribution
of the side chains along the backbone being controlled by the
the relative reactivity ratios of (1) the polymerizable end
10groups on the copolymerized tapered block macromolecular
monomer and (2) the copolymerizable comonomer.
~i .
~ -llb-
~ 22234
3537
The copolymerizable backbone-forming monomers useful
in the practice of the present invention are not limited by
the exemplary classes of compounds men-tioned above. The only
limitation on particular monomers to be employed is their
capability to copolymerize with the polymerizable end groups
of the side chain prepolymer under free-radical, ionic, con-
densation, or coordination (Ziegler or Ziegler-Natta catalysis)
polymerization reactions. As it will be seen from the
description of macromolecular monomers, described hereinbelow,
the choice of polymerizable end groups includes any polymer-
izable compound commercially available. Accordingly, the
choice of respective polymerizable end group and copolymerizable
monomer can be chosen, based upon relative reactivity ratios
~` under the respective copolymerization reaction conditions
suitable for copolymerization reaction. For example, alpha-
olefins copolymerize w.ith one another using Ziegler catalysts,
:
and acrylates copolyl~lerize with acrylonitrile and other
alkyl acrylates. Accordingly, an alpha-olefin terminated
macromolecular monomer copolymerizes with ethylene and alplla-
olefins using a Ziegler catalyst and an acrylate or meth-
acrylate terminated macromolecular monomer copolymerizes
with acrylonitrile, acrylates and methacrylates under free-
radical conditions in a manner governed by the respective
~^ reacti~ity ratios for the comonomers.
As will be explained hereinafter, the excellent
combination of beneficial properties possessed by the graft
copolymers o the present invention are at~ributed to the
large segments of uninterrupted copolymeric backbones and
the integrally copolymerized linear side chains of controlled
molecular wei~ht and narrow molecular weight distribution.
.~ .
-12-
22234
~.23S~
The term "linear", referred to hereinabove, is being
used in its conventional sense, to pertain to a polymeric back-
bone that is free from cross-linking.
T~e side chain polymers ha~ing substantially uniform
molecular weight are comprised of substantially linear polymers
and copolymers produced by anionic polymerization of a mono-
alkenyl-substituted aromatic hydrocarbon and a conjugated diene.
Preferably, the side chain polymer will be different than the
backbone polymer.
It is preferred that at least one segment of the side
chain polymer or the graft copolymers of the present invention
have a molecular weight suficient to manifest the benericial
p~operties of the respective polymer. In other words, physical
- properties of the side chain polymer such as the glass transrtion
~5 temperature (Tg) will be manifest. Generally, as known in the
art, the average molecular weiqht of the segment of the polymeric
side chains necessary to estab:lish the physical properties of
the polymer will be from about 5,000 to abou-t 50,000.
In llght of the unusual and improved physical properties
:.~
possessed by the thermoplastic graf~ copolymers of the present
; invention, it is believed that the monofunctionally bonded
; polym~ric side chains ha~ing substantially uniform molecular
weight form what is known as "~lassy domains" representing areas
of mutu~l solubility of the respective side chain polymers from
; 25 separate backbone copolymexs.
The invention is illustrated further by the ollowin~
examples which, however, are not to be taken as limiting in an~
respect. In each case, all materials should be pure and care
should be taken to keep ~le reacted mixtures dry and free of
contaminants. All parts and percentages, unless expressly stated
to be otherwise, are by weiyht.
-13-
~-~ 22234
3~
Example 1
Preparation of macromolecular monomer having the follow-
ing s tructure: CH3CH2 Cll t CH ~ - CB~B-C- A ' -CH,-CH=CH2
wherein the group designated as "B", "C'l, and "A"' have the mean- -
ings given above.
Terminal polystyrene block, 11,000 molecular weight
Group (B-C-A'3 including tapered block of styrene-isoprene
(C), 21% styrene and 79% isoprene, molecular weight
30,000
Terminated with alpha-olefin
Two liters of purifled benzene were charged to a one gallon
Chèmco reactor and heated to 40~C. The benzene was sterilized
` with the s~c-butyl lithium using l,l-diphenylethylene as an in-
; 15 dicator. Sec-butyl lithium was added until a pale yellow color
was maintained ~or one minute.
8.1 ml. ~11.06% solution in hexane~ of sec-butyl lithium
initiator was added to the reactor, and the benzene solution
developed a red color due to the presence of the diphenylethylene
anion. 95.6 g. o~ styrene monomer was added over a three minute
period whîle maintaining the reactor temperature at ~0C. As
the styrene polymerized, the solution chanaed to red-orange.
Thirty-five minutes after the styrene monomer addition was com-
pleted, a second monomer charge compose~ of 50 g. of styrene and
191.3 g. o~ isoprene was added in one minute. On addition of the
mixed monomer solution, the solution color immediately changed
to yellow, characteristic of the iscprene anion. The reaction
`; temperature was rnaintaine~ at 40C. for 4.5 hours. A~ter the first
two hours, the soluticn color began ~radually to change back to
the red-orallge color of the styryl anion. At the end of this time
2.0 rnl o~ allyl chloride was added to form the alpha-olefin end
g oup. The 40C. reactor temperature was maintained for an
22234
~ 3~3~
additional thirty minutes. On removal from the reactor, the
macromolecular monomer solutlon was stored under nitrogen pressure.
The solution was clear, colorless and of low viscosity (16.6~
solids). GPC analysis of the initial polys-tyrene segment was
made to determine its molecular weight, and it was found to have
a molecular weight of 11,000, and the total mol~cular weight of
the macromolecular monomer was estimated to be 41,000.
.
Example 2
Preparation of macromolecular monomer having the ~ollowing
structure:
CH3CH~CH ~C~2-cH~B-C-A' -C}12CH20-CH2CO-O-CH=C~2
Terminal block of polyst:yrene 10,500 molecular weiglit
Group (B-C-A') including tapered block of styrene-isoprene
~3, 21~ styrens ancl 79~ isoprene, molecular weight
28,000.
Terminated with vinylchloroacetate
Two liters o puriied benzene were charged to a one gallon
Chemco reactor, and heatPd to 40C. The benzene was sterilized
with the sec-butyl lithium using 1,l-diphenylethylene as- the in-
. , .
dicator. Sec-~utyl lithium was added until a pale yellow color
was maintained for one minute.
.5 ml. (ll.n6% solution in hexane) o~ sec-butyl lithium
initiator was added to the reactor, and ~he benzene solution
~. . ,
~; 25 developed a red color due to the presence of the diphenyletllylene
anion. 110.0 g. Qf styrene monomer was added over a three
minute period while maintaining the reactor ~emperature at 40C.
~s the styrene polymerized, the solution color changed to red-
orange. Twent~-five minutes after the styrene monomer addition
was com~leted, a second monomer ch~rge composed o~ 58.6 g. of
styrene and 220.1 g. o isopren~ was added in one minute. On
22234
35~7
addition of the mixed monomer solution, the solution color immedi-
ately changed to yellow, characteristic of the isoprene anion.
The reaction temperature was maintained at 40~C. for 1.5 hours,
at which time the red-orange color of the styryl anion returned.
2 ml. of ethylene oxide was then added to form the colorless
alkoxylate anion. The reactor temperature was maintained at 40C.
for an additional 1.5 hours, after which 2.5 ml. of vinyl chloro-
acetate was added. A~ter 35 minutes the macromolecular monomer
solution was removed from the reactor (21.3~ solids) and stabil~-
ized with 0.2 Ionol CP antioxidant (based on total solids).
Gel permeation chromatography analysis of the initial
polystyrene segment was made and it was determined to have a
molecular weight of 10,500, and the total molecular weight of
; the macromolecular monomer was estimated to be 38,500.
~xampl~ 3
Preparation of macromolecular monomer having the follow-
ing struc~ure:
C~3CH2c~ ~ C~2-CH l B-C-A'-CH2CH2O-CO-C=CH2
~3 l ~ ¦ CH3
Termlnal block of polystyrene, molecular weight 12,500
Group (B-C-A') including tapered block (C) o~ styrene:
isopre~e, ratio lO parts to 90 parts
Total molecular weight of macromolecular monomer 50,000
Terminated with methacrylate
2.5 li~ers of puriied benæene were charged to a one
gallon Chemco reactor, and heated to ~0C. lhe benzene was
sterilized with sec-butyl litlli.um using l,l-diphenylethylene
as an indicator. Sec-butyl lithium was added until a pale yellow
color was maintained ~or one minute.
7.6 ml. (11.6C solution in hexane) of sec-butyl lithium
ini~iator was added to t'ne reactor, a~ he benzene solution
.
22234
,, ~ .
3537
developed a red color due to the presence of the diphenylethylene
anion. 88.7 g. of styrene monomer was added over a two minute
period while maintaining the reactor temperature at 40C. As the
styrene polymerized, the solution color changed to red-orange.
S Twenty-five minutes after the styrene monomer addition was com-
pleted, a second monomer charge composed of 26.3 g. of styrene
and 239.6 g. of isoprene was added in two minutes. On addition
of the mixed monomer solution, the solution color immediately
changed to yellow, characteristic of the isoprene anion. The re-
io action temperature was maintained at 40C. for 3.25 hours, at
which time the red-orange color of the styryl anion had returned.
2 ml. of ethylene oxide was then added to form the colorless
alkoxylate anion. The reactor temperature was maintained at ao oc .
; for an additional 1.25 hours r after which 2.0 ml. of methacryloyl
chloride was added. After 30 minutes, the ma~romolecular monomer
solutior. t.~7~S removed from the xe~ctor (la~5~ soli~s) and stabil-
ized with 0.2% Ionol CP antioxidant (based on total solids).
~` G.P.C. analysis o~ ~le initial polys~yrene segment was
~; made and i~ was determined to have a molecular weight of 12,500,
and the total molecular weight of the macromolecular monomex was
estimated to be 50,000.
Example 4
. . _ .
Preparation of a macromolecular monomer having the follow-
ing structure:
C33C~2-c3 ~ C~2-C~ t 3-C-A'-C~2CH2O-CO-CH=C32
Initial block of styrene, molecular weight 11,000
Group (B-C-A') including tapered bloc~ copolymer (C) o~
styrene-isoprene, ratio 10 parts to 90 parts,
molecular weight 30,000
-17-
~ 22234
~ ~353~
Total molecular weight of macromolecular
monomer ~1,000
Terminated with the acrylate
Two liters of purified benzene were charged to a
one ~allon Chemco reactor and heated to 40C. The ~enzene was
sterilized with the sec-butyl lithium using l,l-diphenyl-
ethylene as an indicator. The sec-butyl lithium was added until
a pale yellow color was maintained for one minute.
8.8 ml. (11.6% solution in hexane) of sec-butyl
lithium indicator added to the reactor, and the benzene solution
developed a red color due to the presence of the diphenyl-
~' ethylene anion. 102 g. of styrene monomer was added over a
two minute period while maintaining the reactor tempexature at
40~C. As the styrene polymerized, the solution changed to red-
orange. Twenty-five minutes aft:er the styrene monomer addition
was colr.plete~, a secon~ monome~ ch~r~e composed of 25.5 ~. of
styrene and 257.0 g. of isoprerle was added in one minute. On
addition of the mixed monomer solu-tion the color immedia~ely
changed to yellow, characteristic of the isoprene anion. The
xeaction temperature was maintained at ~0C. for 3.25 hours t
at which time the red-orange color of the styryl anion had
returned. 2.4 ml. o~ ethylene oxide was then added to form
the colorless al~oxylate anion. The reac-tion temperature was
maintained at 40C. ~or an additional 1.25 hours, after which
2.0 ml. of acrylyl chloride was added. After 20 minutes, the
macromole~ulax monomer solution was removed from the reactor
(16.1% solids) and stabilized with 0.2% Ional C~ antio~idant
(based on total solids).
G.P~C. analysis of the initial polys'c-~-rene segment
was made and -.~as determined to have a molecula~ weigllt of 11,000,
and the total moleculax weight of the macromolecular monomer was
estimated to ~e 41,000.
-18-
- _ ~ Q_
~ ~35~7 22234
Example 5
_
Preparation of a ma~romolecular monomer having the follow-
ing stxucture:
CH3-C~2-~H~CH2-CH1B-C-AI-CH2CH2O-CO-C=CH2
CH3 ~ ~ I CH3
A terminal block of polystyrene, 10,000 molecular weight
A group (B-C-A') including a tapered block tC) o styrene
20 parts, isoprene 80 parts, total molecular weight
; 25,000
Terminated with methacrylate
2.5 liters of purifie~ benzene was charged to a one gallon
Chemco reactor and heated to 40C. The benzene was sterilized
with sec-butyl lithium using l,).-diphenylethylene as an indicator.
Sec-butyl lithium was added until a pale yellow color was main-
tained for 1 minute.
0.013 mole (11.1 ml. of 11.044 solution in hexanQ) of ses-
butyl lithium initiator was added to the .reactor and the solution
deve`loped a red color due to the diphen~le~hylene anion. 130.4
grams of styrene monomer was added over a 3 minute period while
maintaining the reactor temperature at 40C. As the styrene
polymerized, the solution color changed to red-orange. 20 minutes~
after the styrene monomer addition was completedt a second monomer
charge composed of 64.3 grams of styrene and 2~6.1 grams of
isoprerLe (20:80 weight ratio of styrene to isoprene) was added
: .
in 2 minutes. On addition of the mixed monomer solution, the
solution color immediately changed to yellow, characteristic
o~ the isop~2ne a~ion. The reaction temperature was maintained
at 40C for 4.5 hours. 4.5 ml. o~ ethylene ox~-de liquid was
added to ~orm the colorless al~oxylate anion. T'ne reaction
t~mperature was maintained at 40C. for 3 hours, a~ter which time
the solution was colorl~ss. L~1ethacryloyl-chloride ~as then added
to terminate the llvin~ anion. On ~emova]. from the reactor the
macromolecular mono.ner solution was stabili~.ed with a. 2 Ional
CP an~lo~.idan~ (based on total so].ids).
_ - 22234
.Z 35~77
Example 6
Preparation of a macromolecular monomer having the follow-
ing structure:
CH3CH2fH f CH2-CH- - B-C-A'-CH2CH2O-~O-I=CH2
S CH3 L ~ n ` C~13
Terminal styrene block homopolymer, molecular weight 10,000
A group (B-C-A') including a tapered block (C) of styrene
40 parts, isoprene 60 parts, total molecular weight
of tapered block 25,000
Terminated with methacrylate
2.5 li~ers of purified benzene was charged to a one gallon
Chemco reactor and heated to 40C. The benzene was sterilized
using sec-butyl lithium and diphenylethylene as an indicator.
0.0128 moles (lP.9 ml. of 11.4~ solution) of sec-butyl lithium
initiator solution is adde~ to the reactor. 128.6 g~ of styrene
;, monomer was ~dded in 4 minutes while maintaining the reactor
temperature at 40C. 20 minutes after the styrene monomer was
added, a second monomer charge composed of 128.6 g. styrene and
192.8 g. of isoprene, 40:60 weight ratio, was added in 1.5 minutes.
2~ The reaction temperature was maintained at 40C. for 2 hours. At
the end of this time ethylene oxide gas was bubbled subsurlace
i.n the reactor for 3 minutes. The reactor t~mperature was maintain-
ed for 60 minutes. At the end of this time, methacryloylchloride
was added to terminate the reaction.
Example 7
, The tapered blocX macromolecular monomers prepared
~:'
~; accordins to ~xamples 5 and 6 were each copolymerized t~7ith
styrene using an aqueous suspension recipe. The copolymer-
izations were carried out in one quart soda bottles rotated
end-over-end ~or 21 hours in a polymerization bath at 70C.
The final product was very fine particle size beads (2-4 mm.
~20-
,
~ 22234
~ w
~J.~D~31 g'
average diameter). r~he beads were recovered on a 100-mesh stainless
steel screen, washed with the distilled water and dried in a vacuum
oven, The recipe and procedure are described below:
-
Tapered block macromolecular monomer 29.4
Benzene (thiophene free) 23.3
Styre~e 6;7.0
Azo-bis-isobutyronitrile (AIBN) 0.268
Distilled water 300
Lu~iskol K-90
(BASF polyvinylpyrrolidone) 0.50
Procedure
The required amount of macromolecular monomer solution
to obtain 29.4 grams of solids was weighed into a 500 ml. round
bottom flask. The e~cess benzene was stripped of~ under vacuum
at 50C~ using a ro~ary evaporator. During the stripping procedure,
a nitrogen atmosphere was maintained over the macromolecular
monomer solution. The stripped macromolecular monomer solution
was cooled to room temperature under a nitrogen purge, and the
flas~ sealed with a butyl rubber septum.
The initiator (AIBN) was dissolved in the styrene
monomer and the solution charged to the ~lask con~ainlng the
~, stripped macromolecular monomer benzene solution using a 100 ml.
syringe. The ~lask was then shaken until a uniform solution was
ohtained.
The l-~uart soda bottle ~.~as rinsed with ~en ene, acetone,
and distilled water and then dried in a ]50C. forced air oven.
The bottle was cooled to room temperature under a nitrogen urge.
The distilled water and suspension stabilizer (Lu~isl~ol K-90) were
-2~.-
2223
~ ~3~
charged to the bottle, the bottle sealed with a butyl rubberseptum, and purged with nitrogen for 1 hour.
The monomer solution was transferred from the 500 ml.
round bottom flask to the bottle containing the water and
suspension stabilizer using a 100 ml. syringe. The bottle was
capped under a nltrogen blanket using a butyl rubber gasket with
a Mylar linear and placed in the ~olymerization bath.
After 21 hours at 70C. the bottle was removed from
- the polymerization bath. The copolymer beads were recover-
ed by filtering onto a 100-mesh stainless steel screen. The
beads were ~ashed with distilled water and dried 20 hours at
50C. under vacuum. 92.9 grams of copolymer beads were re-
covered. This corresponds to 94% styrene conversion with
32% by weight M~CROMER~ present in the copolymer.
The physical properties of the tapered block macro-
molecular monomer copolymers were determined on compression
molded samples. The macromolecular monomer copolymers were
stabilized with 0.1% Irganox 1076 and 0.4~ U~i-nox 3100 prior
to compression molding. The test bars were compression molded
8 minutes at 380F. Milling of the copolymers formed from
.
macromolecular monomexs for 10 minutes at 290F., compared
; to dissolving the copolymers in benzene and precipitating in
- isopropanol as a means Gf compounding in antioxidants, pro-
duced no significant change in physical properties.
-
.
-22-
.
1 ~:.2æ353t7 22234
.
The copolymer prepared from the macromolecular monomer
of Example 5 had a flex modulus (psi x 105) of 2.72, a heat
distortion temperature of 173F., and Izod impact (ft-lb/in)
notched 0.2, unnotched 3O2; and per cent light transmission of ..
a molded bar (at 6-0 mu) of 62~. The copolymer ormed from the
macromolecular monomer of Example 6 had a flex modulus of 2.75,
heat distortion temperature 178F., Izod impact notched 0.0,
unnotched 2.8, light transmission 65%.
'
. Example 8
The tapered block macromolecular monomer prepared
according to Example 3 was copol.ymerized with.styrene uslng an
aqueous suspension recipe.
rThe copolymars were maLde in a w~ight ratio OI ~ 3
macromolecular monomer to styrene for Sample l and 42:58 for
;~ 15 Samples 2 and~3. 0.4% of azobisiso~utyrylnitrile [AIBN) wa~
added to each, and 35% benzene was added based on the weight of
the styrene for Sample l and 40~ benzene was added for Sample
2 and 3.
Proc~dure
The solution of macromolecular monomer ~14.5% solids
in benzene) for Sample No. l was stripped for 15 minutes and
in Samples 2 and 3 for 25 minutes at 50C. under about 70 mm
of ~g. Copolymerization was carried out for 21 hou~s at 70C.
. Results: All of the bottles formed stable, small
2$ particle size suspensions (about 3 ~m diameter beads) usina tri-
calcium phosphate as a suspension stabilizer. The bottles were
--23--
~ ~3~37 22234
stripped using vacuum immediately after removal from the 70C.
bath to remove benzene. After stripping for 30 minutes, 75 ml
of a 50/50 concentrated HCl in distilled wate~ solution was
- added to the bottles (to dissolve calcium phosphate). The bottles
were replaced in a 60~C~ bath. A~ter lO minutes at 60C. the
beads in all the bottles had coalesced. The bottles were removed
from the bath and allowed to cool at room temperature. After
cooling to room temperature, the coagulated beads broke apart
easily. The beads were washed with two liters o~ 0O3 N.HCl and
then with distilled water. The washed beads were dried 20 hours
at 50C. under vacuum. Analysis of the beads showed that the
copo~ymerization reaction went substantially to completion.
Samples of each of the copolymer beads were dissolved in
be.nzene or gel permeation chromatography (G.P.C.). None of the
s~nplas had a noticeable ael content.
In Sample No. 1 the ratio of macromolecular monomer
; to styrene was 31:69. It had normal molecular weight dis-
tribu~ion centered at about 27 counts on the high molecular
weight banX. A slight low molecular weight shoulder was visible
at 32 counts (due to dead polystyrene chains initially pr~sent
in the macromolecular monomer). The sample had no high molecular
weight shoulder. The solution passed through the syringe ilter
without difficulty indicating no signi~icant amount o~ microgel
in the copolymer.
Sample No. 2 had a ratio of macromolecular monomer
to styrene of 42:58. The molecular weight distribution was
:
.
-24-
-
,~ 222~4
3~3'7
somewhat broader than for Sample No. l and centered at about
26.5 counts on the high molecular weight bank. A slight low
molecular weight tail was visible at about 32 counts. The
,sample had a significant high molecular weight tail. The
5 solution was difficult to get through the syringe filter in- ~
dicating microgel present in the copolymer. The presence of
microgel was also indicated by the high molecular weight tail.
Sample No. 3 also had a weight ratio of macromolecular
monomer styrene of 42:58, the sample was very dificult to get
through the syringe filter and plugged the G.P.C. columns so no
chromatograrn could be obtained.
Example 9
-
Two portions (28 parts each) from Sample No. 1 of
Example 8 were taken, one designated Sample A and thè other
Sample B. To each there was added 0.3% Irganox 1076, a commercia
antloxidant, 0.9% Uvi-noY~ 3100 also an antioxidant, alld ~0~
parts of benzene as solvent. To Sample B there was also added
15.4 parts (14.5% solution in benzene) of macromolecular monomer
from Example 8, that is, having a terminal block of polystyrene,
molecular weight 12,500, a tapered block of a copolymer of
styrene and isoprene in the ratio of 10:90 ~y weight having a
molecular weight o 37,500/ terminated with methacrylate.
Each solution was precipitate,d wlth about 4 liters o iso-
propanol. l~he precipitated polymers were recovered by filte~ing
onto filter paper. Both samples were dried 4 l/2 hours at 50C.
under vacuum. The dried samples we~e compression molded for
testing and meas~ring of the physical properties. Sample A
had a flex modulus of 2.50 psi x lO5, a~d Izo* impact (2 pound
head) of 0.1, 0.2 rlotch and 3~2, 4.0 unnotched. The appearance
o the molded sample was clear with a pala yellow coloring.
-2~-
~ 3~7 22234
For Sample B, the flex modulus was 1.71 x 105 psi. The Izod
impact with the 2 lb. head, notched was 1.4 and 3Ø The Izod
unnotched with the 5 lb. head did not break~ The appearance o~
the sample was claar with a pale yellow coloring and bluish
haze.
Sample C was taken from Sample No. 2 of Example 8.
19.0 parts were mixed with 0.3 parts of Irganox, 0.~% Uvi-nox
3100 and 600 parts of benzene. The solution was precipitated
with about 4 liters of isopxopanol. The precipitate was re-
covered by filtering onto filter paper and dried for 17 hours
at 50C. under ~acuum. The sample was first molded into a
sheet ~1 minute at 310F.). Several strips were superimposed
and molded under heat and pressure (8 mins. at 380F.) into
bars whi.ch were 5 ins. long, 1/2 in. wide and 1/8 in. thic~.
The sample contained macromolecular monomer and styrene ~o-
polymerized in the weight ratio 42:58. It had a flex modulus
1. 77 psi x 105 and notched lzod o~ 0.6, 0.6 (ft. lb/in.) with
a 2 pound head, an unnotched Izod 16.8 with a 10 pound head. It
-~ was clear and had no haze and had a pale yellow coloring.
Z0 Sample D was prepared from Sa~ple No. 3 of Ex~nple 8
in the amount o~ 19.0 parts by weight of the copolymer mixe~
with 10.5 parts by wei~ht (14.5% solution in benzene) o~ macro
molecular monomer having the terminal block of styrene 12, 500
molecul~r weigh~, the tapered copolymer block of styrene-
isoprene at 10:90 ratio, molecular weight 37,500, terminated
with methacrylate. To that was added 0.3 Irganox, 0.9% Uvi nox
and 600 parts by weight of benzene. The solution was precipitat-
ed with abou~ 4 litexs of isopropanol; the precipita~ed polymer
was recovered by filterin~ onto filter paper and dried 17 hours
at 50C. under vacuum. The sample was mol~ed into a sheet
(1 minute at 310F.). Bars were molded from strips cut from
the prepressed sheets (8 minutes at 380~F.). The fleY. modulus
-26-
~.2353~7 .
was 1.35 psi x 105; the Izod impact notched was 1.0 (ft. lb/in.)
for one sample, another sample did not break; the unno~ched Izod
with a 10 lb. head did not break. The sample was clear without
haze and had a pale yellow coloring.
Sample E was made from a mixture of 6~ parts by weight
(14.5% solution in benzene) of macromolecular monomer of Example
8, that is, having a styrene terminal block OL molecular weight
12,500, a tapered block copolymer of styrene and isoprene ratio
lO:90r molecular weight 37,500, terminated with methacrylate, 20
parts of Dow polystyrene X-grade, 0.3 parts Irganox antioxidant,
0.9 parts Uvi-nox antioxidant and 600 parts benzene. The solution
in benzene was precipitated with about 4 liters of isopropanol,
the precipitate was recovered by iltering on filter paper and
drylng for 17 hours at 50C. under vacuum. ~he sample was first
molded into a sheet (1 min. at 310F.). Bars were molded from
s'~i-ip~ pL~as~ . 380~F). ~Ll~ ~iex
modulus was 0.066 psi x 105; the Izod impact 2 lb. head notched
was 1.4, 1.6 (ft. lb/in.); the unnotched Izod did not break with
the 10 lb. head. Standard ASTM methods were used in testing.
The fIex modulus was by method D-790-66 and the impact modulus was
determined by test D-256-56 methods A and C. The sample was
opaque. These tests and observations indicate phase separation
within the sample~
Example 10
A macromolecular monomer was prepared having the follow-
ing structure:
CB3CB21H ~ CB2 ~ j B-C-A'-CB2CB20-~0-CB=CB2
A terminal block of styrene of molecular weight 11,000
A group ~B-C-A') including a tapered block cGpolymer (C)
of styrene and isoprene iIl the weight ra;-io or
-27-
~ 2Z~4
3~37
10:90, molecular weight 30,000
Terminated with acrylate
The macromolecular ~onomer was copolymerized with styrene
containing 0.4~ by weight of AIBN. The monomer mixture contained
35.1 parts of macromolecular monomer, 27.9 parts of benzene, 80.3
parts of monomeric styrene, and 0.321 parts AIBN. The 1 quart
polymerization bottle was charged with 400 parts of boiled,
nitrogen-purged distilled water, 1 part of tricalcium phosphate
and 126.~ parts of monomer solution (described above). The pro-
cedure used for the suspension polymeri~ation was described in the
previous examples. The copolymerization was caxried out for 21
hours at 70C. The benzene was stripped from the mixture for 18
mînutes at 50C. under about 65 mm of mercury absolute pressure.
The polymer was in the form of beads having a diameter about 3 mm
average. The bottles were stripped for 30 minutes through syringe
needles using a vacuum pumpO After strippin~, 75 ml of a 50%
aqueous solution of concentrated HCl was added. The bottles were
replaced in the polymerization bath at 55C. The beads remained
discrete and wexe removed from the bath after 30 minute~s, washed
with 2 liters of 0.3 N. ~Cl, rinsed with distilled water, and dried
in 24 hours at 50C. using a vacuum pump. 102.4 parts by weight
~ of beads were reco~ered having a true solids content of 95.7%.
; The percent s~yrene conversion was 94.6~ and the percent of
macromolecular monomer in the copolymer was 31.5%. The presence
of rubber in the copolymer was 20.7%.
A solution was prepared from the copolymer with 50 parts
of copolymer, 0.4 parts of Irganox 1076, 1.2 parts of Uvi-nox
3100 and 600 parts of benzene. The solution was pxecipitated
with about 4 liters o~ isopropanol, the precipitated polymer
was recov2red by filtering onto Whatman ~o. 1 paper and dried for
6 hours a~ 50C. under vacuum. A 60 mil sheet of precipitated
sample ~7aS molded ~or 1 mlnllte at 310F. The slleet was clear and
-2~-
22~4
3~3'~
tough. Test bars were molded from strips cut from the prepressed
sheets for 8 minutes at 380F. These bars were clear and stiff.
As a co~parison, the equivalent amount of styrene was
polymerized in the presence of a nonfunctional ~apered block
macromolecular monomer having s~stantially the same composition
as that described a~o~e the present example. A comparison of the
physical prope~ties of these two samples is shown below:
Macromolecular Flex Izod Impact Heat Dis- Appearance
monomer Modulus (ft lbs/in) _ tortion of Molded
(~si x 105) Notched Unnotched Temp(F) Bar
non-functional 0.14 3.1 8~6 ~ 78 opaque
Sll~SI 10:90)30A 2.42 0.3 4.9 177 clear
'rhe clarity and improved physical properties of the copolymer
compa~ed to the control demcnstrate the functionality of the
Sll(SI 10:90)30A tapered block macromolecular monomer.
Exam~le 11
Preparation of Polystyrene-]?olyisoprene Macromolecular
Monomer Terminated with Allyl Chloride
_
To a l-gallon Chemco reactor, 2.5 lite~s of purified
20 ~enzene was added, and heated to 40C. After sterilization with
sec-butyl lithium using diphenylethylene as an indicator, 15.3 ml.
(0.0193 mole) of sec-butyl lithium ~12~ in hexane) was added via
hypodermic syringe. 193 g. of styrene monomer was added in 5
minutes while maintaining the reactor tèmperature at 40C. 6
minutes after styrene monomer was added, 193 g. of isoprene monomer
was added in 4.5 minutes. The reactor was held at aooc. for
60 minutes, then 2.4 ml. of allyl chloride was added to terminate
the reaction. The alpha-olefin terminated polystyrene-po]yisoprene
macromolecular monomer has a structural formula represented as
follo~s:
-29-
.
~2234
3S~3~
CH3CH2 - C~ ~ C~ _ C ~ C 2 ~CH2 2 2
wherein ~ is a va~ue such that the molecular weight of the poly- -
styrene is a~out 10,000 and m is a value such that the molecuïax
weight of the polyisoprene segment of the diblock macromolecular
monomer is about lO,000. In a similar manner, graded or
tapered bloc~ macromole-~ul~x- monomers are prepared by substitut-
~; ing e.g. a lO:90 to 40:60 mole ratio of styrene to isoprene
mixture for the isoprene in the foregoing procedure.
Example 12_
~, Preparation of Graft Copolymer from Polystyrene-
Polyisoprene Macromolecular monomer Terminated
with All~l Chloride and Propylene _ _
~ one-half-gallon Chemco reactor, 60 g. of t~e ~l~ha-
ole~ln~~erminated diblock macromolecular monomer (polystyrene-
: ., .
- pol~r~soprene terminated with allyl chIoride~ prepared in
~he previous example was charged together with 1.5 liters of
dry n-heptane. The reactor was purged with nitrogen for 40
minutes. 30~ml. of diethyl alumin~n chlorid (25% in n-heptane)
was added, followed by 2.05 g. of ti~anium trichloride. Th~
reactor was heated to 75C, and propylene gas was introduced
to the reactor at the rate of l liter/minu Le . Polymerizati~n
was carried out at 75C~ at 20-25 psi pressure whlle feeding
propylene at the avera~e rate of O.S liter/minute. Arter 2
hours, the reaction was terminated by the addition or ethanol.
I The resulting copolymer was washed with dllute sodium hydroxlde
solution and dried in a vacuum oven. IR analysis showed th~t
the diblock macromolecular monomer was incorporated into the
polypropylene backbone The physical properties of the copolymer
ere tested and the results of the tests were as LOllOWs
-30-
J~
3~
Tensile Strength4970 psi
Yield Strength47~0 psi
% elongation 810%
Flexural Modulus 2.05 x 105 psi
Heat Distortion
Temperature 144F
- Izod Impact 1.0 ft. - lb./in.
Similar copolymers are also made from the tapered block
monomers described in Example 11.
.
Example 13
Preparation of Polystyrene-Polyisoprene
Macromolecular monomer Terminated with
Allyl Chloride
-
To a l-gallon Chemco reactor, 2.5 liters of dry benæene
was added and heated to 40~C. A~ter sterilization with sec-butyl
lithium using diphenyl ethylene as ar~ indicator, 15.8 ml.
~(O.O~gg mole) o, sec-butyl lithium (12~ i~ haxane) '.JaS addecl ~ia
hypodermic syringe. 80 g. of styrene monomer was added while
malntaining the reaction tempera~,ure at 40C. Thereafter, 319 g.
of isoprene monomer was added and polymerization was carried out
at 40C. ~or 1 hour, and the living diblock polymer was terminated
with 3.0 ml. of allyl chloride. The dibloc~: macromolecular
monomer had a ~ormula represented as ~ollows:
C}~ -C~ - C - - ~ CH2 - CH ~ C~2 /CH~l _ C~2-C~ = C~2
wherein n is a value such that tihe molecular weight o polystyrene
is about 4,000 and m is a YaluQ such that the ~olecul?.r wei~ht of
polyisoprene is about 16,000. Analysis o~ the dibloc~ macro-
molecular monomer by gel permeation chromatography reveals that
-31-
~ - 22234
3537
the molecular weight distri~ution of the polymer is extremely
narrow, i.e., the ratio of Mw/Mn is less than about 1.1. In a
similar manner, graded or tapered block macromolecular monomers
are prepared by substituting e.g. a 10:90 to 40:60 mole ratio
of styrene to isoprene mixture for the isoprene in ~he foregoing
procedure.
Example 14
Preparation of Graft Copolymer rom Polystyrene-
polyisoprene Macromolecular Monomer Terminated
with Allyl Chloride, and Ethylene
.
To a one-half-gallon Chemco reactor, 300 ml. o the di-
bloc]c macromolecular monomer as prepared in Example 13 (40 g. on
dry basis) was charged together with 1.2 liters of dry cyclohexane.
The reactor was purged with high purity nitrogen ~or 50 minutes.
22 ml. o ethylaluminum sesquichloride solution t25% in heptane)
was added via hypodermic syringe. Ethylene was introduced to
the reactor until the pressure reach~d 44 psi, and the mixture
was stirred as rapidly as possib:Le. 0.2 ml. of ~anadium oxytri-
chloride was iniected and polymexization started immediately.
~uring the addition of the vanadium oxytrichloride, the temper-
ature rose from 25C. to 60C. As the pressure dropped, ethylene
was fed at the rate of 2 liters/minute. Polymerization was
carried out for 12 minutes, and terminated by the addition of
10 ml. of ethanol~ The polymer was purified by washing wlth
cyclollexane, dilute sodium hydroxide solution, and dried in a
vacuum oven. U.V. analysis of the copolymer showed that the
copolymer contained 24~ of the d~block macromolecular monomer.
- The physicaL properties o, the copolymer were tested and the
results of these tests are as follows:
Yield Stxength 2500 psi
Tensile Strength 2160 psi
~ Elongation 490~O
Fle~ural Modulus 0.6 x 105 psi
~32-
~.235~ 22234
Heat Distortion
Temperature 98F
Izod Impact 12.8 ft. - lb.~in.
(specimen did not break)
Simil~r copolymers are also made from the tapered block
monomers described in Example 13.
.
Example 15
Preparation of Polystyrene-Polyisoprene
. Macromolecular Monomer Terminated with
Allyl Chloride
To a l-gallon Chemco reactor, 3.0 liters of purified
benzene was added and heated to 40C. After sterilization with
sec-butyl lithium using diphenyl ethylene as an indicator, a6.5
ml. (0.0585 mole3 of sec~butyl lithium (12% in hexane) was
added via hypodermic syringe. 761 g. of styrene monomer was
added in 15 minutes while maintaining the reaction temperature
at 40C. 5 minutes after complotion of styrene monomer addition,
~` 410 gO of isoprene monomer was added in 4 minutes. The reaction
was held at 40C.~for one hour, then the reaction was terminated
~y the addition of 15 ml. of allyl chloride. The diblock macro-
molecular monomer had a structural ~ormula as described in
~- Examples 11 and 13 hereinabove, wherein the value of n was such
that the molecular weight of polystyrene was ~bout 13,000 and
~` the value of m was such that the molecular weight of~polylsoprene
was 7,000. The diblock macromolecular monomer was analyzed by
gel permeation chromatography and this analysis re~ealed that
the molecular weight distri~ution of the polymer was extremely
narrow, i.e., the .~lw/Mn ratio was less than about 1.1. In a
similar manner, ~raded or tapered bloc~ macromolecular monomers
are prepared by substituting e.g. a 10:90 to 40:60 mole ratio
of styrene to isoprene mixture for the isoprene in the ~oregoing
procedure.
~- 22234
~.23~37
Example 16
Preparation of Graft Copolymer from Polystyrene-
Polyisoprene Macromolecular Monomer Terminated
with Allyl Chloride and Ethylene
,
To a one-half-gallon Chemco reactor, 200 ml. of the di-
block macromolecular monomer prepared in Example 15 ~40 g. on
dry basis) was charged together with 1.3 liters of cyclohexane.
The reactor was purged with high purity nitrogen for 1 hour.
22 ml. of ethylaluminum sesquichloride solution (25~ in heptane)
was added. Ethy].ene was introduced to the reactor until the
pressure reached 44 psi. Thereafter, 0.2 ml. of vanadium ox~tri-
chloride was added and polymerization started immediately, and
the temperature rose from 27C to 55C. As the pressure dropped,
ethylene was fed at the rate of 2 liters/minute. Polymeri3ation
was carried out for 8 minutes, and terminated by the addition
of 10 ml. of ethanol. The polymer was purified by washing with
dilute sodium h~Jdroxide solution" cyclohe~ane, and dried in a
vacuum oven. U.V. analysis showed that the copolymer contained
38.5% of the di~lock macromolecu:Lar monomer. The physical
2Q properties o~ the copolymer were tested and the results are as
follows:
Yield Strength 5790 psi
Tensile Strength5920 psi
~ Elongation 77%
Flexural Modulus1.6 x 105 psi
Heat Distortion
Tempexature 120~F
Izod Impac~ 1.0 ft. - lb./in.
5imilar copolymers are also made from the tapered block
monomers described in ~xample lS~ -
-34-
~ 22234
353~
Example 17
Preparation of Polystyrene-Polyisoprene
Macromolecular Monomer Terminated with
Allyl Chloride _ _ _ _
To a l-gallon Chemco reactor, 2.5 liters of purified
benzene was charged, and heated to 40C. After sterilization
with sec-butvl lithium using diphenyl ethylene as an indicator,
35.1 ml. (0.044 mole) of sec-butyl lithium (12% in hexane) was
added hypodermic syringe. 442 g. of styrene was added in 13
minutes while maintaining the reactor temperature at 40C.
Ten minutes after styrene monomer was added, 88.4 g. of isoprene
monomer was added in 4 minutes. The reactor was held at 40C
for 30 minutes, then 3.6 ml. of allyl chloride was added to
terminate the reaction. The recovered diblock macromolecular
monomer had the same structural formula as represented in Examples
11 and 13 hereinabove, with the exception that the value of n
was such t~a~ poi~styre!l~ had a r..olec~la~ igh~ of abollt 10 n~o
and the value of m was such that the molecular weight of poly-
isoprene was about 2 J 000 . The polymer was analyzed by gel
permeation chromatosraphy and ~he analysis revea~ed that the
moleculax weight dlstribution of the polymer was very narrow,
i.e., ~he Mw/Mn ratio was less than about 1.1. In a similar
manner, graded or tapered block macromolecular monomers are
prepared by substituting e.g. a 10:90 to 40:60 mole ratio of
styrene to isoprene mixture for the isoprene in the foregoing
procedur e .
'
:.
-35-
22234
Example 18
Preparation of Graft Copolymer OI Polystyrene-
Polyisoprene Macromolecular Monomer Terminated
with Allyl Chloride and a Mixture of Ethylene
a Propylene _ _
To a one-half-gallon Chemco reactor, 155 g. of 19.3% by
weight of the diblock macromolecular monomer prepared in Example
17 solution (30 g. on dry basis) was charged together with 1.6
liters of purified cyclohexane. 22 ml. of ethylaluminum
sesquichloride solution (25~ in heptane) was added via hypodermic
syringe. Then 19 liters (35 g.j of propylene gas was intro-
duced into the reactor. As soon as 0.2 ml. o vanadium oxytri~
chloride was in~ected, polymerization was started by continuous
feed of ethyleneO Ethylene was added to the reactor at the rate
of 2 liters/minute for 14 minutes (35 g.) Polymerization was
carried out for 24 minutes, and terminated by the addition of
isopropyl alcohol.
The copolymer solution was placed in a stainless steel
beaker and 1 liter of dilute sodium hydroxide solution and 1 g~
o Irganox 1010 antioxidant was added. The mi~ture was stirried
by Arde-Barinco Mixer to remove catalyst residue from the polymer.
~he copolymer was coagulated and dried, and evaluated as~(l)
thermoplastic elastomer, (2) alloying agent for blending
commercial EPDM and polyisoprene for developing high impact
plastics, (3) EP xubber which can be cured ~ith conventional
diene-based rubbe, to improve compatibility and ozone resistance.
Similar copolymers are also made from the tapered block
monomers described in E~ample 17.
-~6-
3 ~3~ 2223~
Example 19
Preparation of Polystyrene-Polyisoprene
Macromolecular Monomer Capped with Ethylene
Oxide and Terminated with Methacrylyl Chloride
s A stainless steel reactor was charged with 195.22 Xg. of
purified benzene. The reactor was heated to 40C and the solvent
and reactor were sterilized with sec-butyl lithium using diphenyl
ethylene as an indicator. Following sterilization, 126.58 g.
(1.9764 moles) of sec-butyl lithium (12% in hexane) was added
to the sterilized solvenk, followed by the addition of 19.47 kg
of styrene over a period o 30-45 minutes, while maintaining
the reactor temperature at 36-42C. Following the addition of
the styrene, 48.62 kg. of isopxene was added to the reactor
followed by the addition of 0.38 kg. of ethylene oxide to "cap"
the diblock living polymer. The "capped" diblock polymer was
terminated by the addition of 0.22 kg. of methacrylyl chloride
to obtain th~ methacrylic acid ester repr2sent~d by the ~ormula:
C~3CH~- CH ~ CH~-C~ ~ CH~ ~ CH2 ~ C~2C~2- O- C- f = c~2
CH3 ~ ~m CH3
wherein n is a value such that the molecular weight of polystyrene
is about 10,000 and m is a value such that the molecular weight
o polyisoprene is about 25,000. Analysis of the dibloc~ macro-
molecular monomex by gel permeation chromatography reveals that
the molecular weight distribution of the polymer is extremely
narxow, i.e., the ratio of ~w/Mn is less than about 1.1. Follow-
ing reco~ery of ~e macromolecular monomer, 68 g. o Agerlite
Superlite (anti-oxidant) was added to the polymer to stabilize
it against premature ox dation.
The procedure of Example 19 was repeated using in place
of me~lacrylyl chloride, an equivalent amount of maleic anhydride
-37-
-~- 2223~
~L~.;23~3~
to produce the maleic half ester of the polystyrene-polyisoprene
diblock macromolecular monomer having the formula:
C~3CH2 CH ~ CH2- CH- - CH2\ CH2 T C~2CH2 O ~ ~H
wherein n and m are positive integers as hereinabove defined.
The graft copolymer was blended with polystyrene (DOW 666)
to impart exceIlent properties. In a similar manner, graded or
tapered block macromolecular monomers are prepared by substitut-
ing e.g. a 10:90 to 40:60 mole ratio of styrene to isoprene
mixture for the isoprene in the foregoing procedure.
.
~ ~ ~x~n1.~ 2n
,
Preparation of Graft C'opolymer from Me~h-
acrylate Ester Terminal:ed Polystyrene-
Polyisoprene ~acromolecular Monomer and Styrene
~' , - .
`~ A suspension copolymerization using the methacrylate
~;~ 20 ester terminated polystyrene-polyisoprene diblock macromolecul~r
monomer prepared in Example 19 was conducted by the procedure
described below. An aqueous solution and a monomer solution
were bo~h Lreshly prepared before use. The ingredients of the
aqueous stabilizer solution and monomer solution were as follows:
A~ueous Stabilizer Solution
Disti]led Water 375 g.
Polyvinyl
Pyrrolidone 0.625 g.
(Luviskol K-90)
Monomer Solution
Methacrylate terminated
macromolecular monomer
(E~ample 19) 75.~ g.
-38-
2223~
3~;37
Styrene 177 g.
Benzene (solvent? 52 g.
AIBN
(polymerization
initiator) 1.32 g.
The aqueous stabilizer solution was charged to a rinsed
quart bottle, and the bottle was capped with a butyl rubber
gasketed cap having a Mylar film lining. The bottle was purged
with nitrogen ~ia syringe needle before introducing the monomer
solution. 146 g. of monomer solution was then charged to the
bottle with a hypodermic syringe, and the bottle was placed in
a bottle polymerization bath and rotated at 3C rpm at 65C for
20 hours. The suspension was then cooled, filtered, washed
with water, air dried, and screened at ambient temperature. 117 g.
of the copolymer was recovered, representing a 95% conversion of
styrene.
The chemically joined, phase separated graft copolymer
was~ compression molded to a clear plastic and had the ollowin~
physical properties:
Flexural Modulus 190,000 psi
(13,360 kg./cm3)
Heat Distortion
Temperature 170F (77C)
Izod Impact Strength 1.1 ft./lb. in. to
(Notched) 9.5 ft./lb. in.
.
As it can be seen from the above data,~ the copolymer had
remarkable physical properties and had the added ad~antage of
being a clear plastic.
In a similar manner, graded or tapered bloc~ macro-
mclecular monomers are prepar2d by substituting e.g. a 10:90 to
~0:60 mQle ratio of styrene to isoprene mixture for the isop ene
in the foregoing procedure.
.
-3~-
~ 3~3~ 22~34
The capability of being injection molded, and the lack
of extractable curing ingredients are among the advantages offer-
ed by the novel macromolecular monomex graft copolymers of the
invention.
Polyblends Employing Macromolecular
Monomers as Alloying Agents
Polyvinyl chloride blends with low levels of the
macromolecular monomer/polyacrylate graft copolymers o the
invention provide products that are clear, have improved pro-
cessing and high impact properties. Notched Izod impact
strengths of 22 ft. lbs.~inch are obtained with little loss in
1exural modulus in rigid polyvinyl chloride blends containing
as little as 3% of the macromolecular monomer/poly(butyl acrylate)
gra~t copolymer. The graft copolymers of the invention also
function as processing aids by improving polyvinyl chloride
~usion in milling and compression molding. The graft copolymers
also impart high strenyth to higher molecular weight polyvinyl
chloride polymers, such as Vygen llO and 120, when low levels
of the graft copolymer (macromolecular monomer/poly(butyl
2n acrylate) is blended after the polyvinyl chloride .is banded on
the mill.
In addi~ion to using the rubbery polystyrene/butyl
~; acrylate graft copolymer as an alloying agent to polymers of
vinyl chloride, the addition of this rubbery component can also
~ 25 be added to polymers of styrene or styrene-acrylonitrile co-
; polymexs for impact engineering plastics. The polyvinyl chloride
polyhlends witll the sraft copolymers have e~ceptionally high
-40-
22234
3~;3~
impact strength and are useful' in pipe, siding, downspouts,
cases, etc. This is unexpected because polyvinyl chloride is
known for its low impact strength. Poly(methyl methacrylate)
- also has low impact strength, however, when a polymer of methyl
methacrylate is either blended or copolymerized with the lower
Tg or rubbery macromolecular monomers of the invention, the
impact strength is enhanced.
The graft copolymers of the invention which have
tapered ~lock polystyrene side chains, improve the melt rheology
of those polymers having a poor melt rheology and are difflcult
to process when small amounts of the graft copolymer is blended
with the polymer. Examples of polymers which can b~ blended
with the graft copolymers of the invention to improve the melt
rheology include polymers of methyl methacrylate, acrylonitrile,
~;~ 15 and others.
The following chemically joined, phase separated combin-
ations of systems can now be made in accordance with the practice
o~ the present invention:
" , .
1. Low Tg disperse phase in high Tg matrix ~impact
plastics).
. High Tg disperse phase in low Tg matrix (thermoplastic
elastomers).
3. High Tg disperse phase in crystalline polymer
~' matrixO
4. Low Tg disperse phase in crystalline polymer
matrix.
5. High Tg disperse phase in hi~h Tg matrix.
; ` ' .
~ j.~d9~3~9.3~
When the macromolecular monomers of the present in
~ention are copolymerized with acrylate monomers, the product
is a graft structure with a low Tg backbone as the matrix and
with the macromolecular monomer as the disperse phase. The
polymer exceeds the strength properties of vulcanized acrylic
rubbers. The macromolecular monomer-acrylic copolymers are
thermally reformable and scrap material can be re-processed,
whereas vulcanized rubbers cannot be re-processed. By varying
the composition of the acrylic monomers and the macromolecular
monomers, the thermoplastic copolymers range in properties from
snappy elastomers to true plastics.
Copolymerization of a high Tg macromolecular monomer
with a rubber-forming monomer also allows one to use the graft
copolymer as an alloyiny agent for dispersing additional rubber
to make new impact plastics. Similar results are obtained
using a suitable tapered block macromolecular monomer with an
appropriate elastomer.
Styrene-based macromolecular monomers with the appro-
priate end group, as demonstrated :in the above examples, are
copolymeri2ed with the following monomers, mixed ethylene-
propylene, ethylene, propylene, acrylonitrile, methyl meth-
acrylate, acrylics, isocyanates, and epoxides. Isoprene and
tapered block macromolecular monomers are particularly suited
as being copolymerized with vinyl-containing monomers such as
~` 25 styrene, styrene-acrylonitrile, ethylene, mixed ethylene and
propylene, and propylene.
.
:`''
. ~ . ~
-~2-
_~Jj
-
~L~ 2~3~ ~
One of the most preferred embodiments of the present
invention comprises a chemically joined, phase separated
thermoplastic gra~t copolymer of:
1. From about 1% ~o about 95% by weight of a
polymerizable comonomer selected from
a. alpha-olefins of the formula:
CH2 - CHR
wherein R is hydr~en, alkyl or aryl radicals
containing one to about 16 carbon atoms,
b. a comonomeric mixture of ethylene and
propylene,
c. a diene selected from butadiene and isoprene,
d. an ethylenically-unsaturated monomer containing
at least one vinylidene
CH2 = C - group selected ~rom acrylic acid,
methacrylic acid, the alkyl esters of acrylic
and methacrylic acid, acrylonitrile, methacrylo-
nitrile, acrylamide, methacrylamide, N,N-dimethyl-
acrylamide, vinylidene cyanide, vinyl acetate~
vinyl propionate, ~inyl chloroacetate, fumaric
acid ana esters, ma~eic anhydride acids and
esters thereof; and copolymerized with
~ ,~ 7
,. "
-~3-
. ~.
'
:. ~ , ''' ' ' ,
3~3~
2. A polymerizable tapered block macromolecular
monomer of the formula:
I - A - B - C - A' - X
wherein I is the residue of an anionic initiator,
A and A' are each polymeri~ed mono-alkenyl-
substituted aromatic hydrocarbons, B is a pol~mer
of a conjugated diene, C is a tapered or graded
copolymer of such a mono-alkenyl-substituted
aromatic hydrocarbon and a conjugated diene, and -
X is a polymerizable end group containing either :;
a vinyl moiety, a vinylene moiety, a glycol moiety,
an epoxy moiety, or a thioepoxy moiety~ said
tapered block macromolecular monomer having a
molecular weight in the range of from about 5,000
to about 50,000, said tapered block macromolecular
lS monomer being ~urther characteri2ed as having no
: more than one ~inyl moiety, vinylene ~oiety,
glycol moiety, epoxy moi~sty or thioepoxy moiety
on the terminal por~ion per linear copolymer chain.
Preferably, the macromolecular:monomer has a sub-
:
: 20 stantially uniform molecular weight distribution
such that its ratio of Mw/Mn is less than about 1.1.
The polymerizable monofunctional macromolecular monomer
is preferably a tapered block copolymer comprising a polymer of
a mono-alkenyl-substituted aromatic hydrocarbon "A" having a
: 25 molecular weight~in the range of from about 2,000 to about 25,000,
preferably a molecular weight in the range of from about 5,000
to 25,000~ and more preferably in the range of from about 5~000
: ~ '- ' '
: 30 ~
` ~ `h- --4 4-- ~
22234
~ 35;3~ ` -
to about 15,000. The polymer of the mono-alkenyl-substituted
aromatic hydrocarbon is chemically bonded to a group designated
as "B-C-A"', wherein the group designated as "Bl' is a polymer
of a conjugated diene, the group designated as "C" is a tapered
or graded block of a conjugated diene and a mono-alkenyl-
substituted, aromatic hydrocarbon, and the group designated
as "A"' is a polymer of a mono-alkenyl-substituted aromatic
hydrocarbon. Preferably the conjugated diene is butadiene or
. isoprene. The molecular weight of the group "B-C-A"' is between
~bout 1,500 and 4$,000, preferably in the range of from about
7,000.to 35,000, and more preferably in the range of from
about 10,000 to 35,000.
~ ile the invention has been described in connection with
specific embodiments thereof, it will be understood that it is
ca~able of further modif.ication, and this application is intend-
ed to cover any va~iations, uses, or adaptations of the invention
followingr in general, the principles of the invention and
including such departures from the present disclosure as come
within known or customary practice in the art to which the
invention pertains and as may be applied to tne~essential
features hereinbefore set forth, and as fall within the scope
of ~he invention.
.
-a~-
