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Description  |
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BACKGROUND
This application concerns star polymers and their preparation with
functional acrylic arms made by group transfer polymerization (GTP) and
cross-linked cores made by condensation reactions involving the functional
groups on the arms.
1. Preparation of Hydrocarbon Star Polymers
Star polymers derived from unsaturated hydrocarbon monomers, such as
styrene, butadiene and isoprene, have been obtained by preparing
lithium-terminated "living" polymers via anionic polymerization and then
coupling the "living" polymer chains by reacting them with various
polyfunctional linking agents. This has usually produced hydrocarbon star
polymers with relatively few (3-12) arms. Hydrocarbon star polymers with a
larger number of arms (e.g., 15-56) have been obtained by sequential
anionic polymerization of difunctional monomers (e.g., divinylbenzene)
with monofunctional monomers (e.g., styrene) or with monomers that behave
as monofunctional monomers (e.g., isoprene). Both methods of preparing
hydrocarbon star polymers have been reviewed by B. J. Bauer and L. J.
Fetters in Rubber Chem. and Technol. (Rubber Reviews for 1978), Vol. 51,
No. 3, pp 406-436 (1978).
A. Aoki et al., U.S. Pat. No. 4,304,881 (1981), prepared styrene/butadiene
"living" polymers by anionic polymerization and then coupled them by
reaction with silicon tetrachloride to produce a 4-arm star polymer having
a silicon core in Example 4.
H. T. Verkouw, U.S. Pat. No. 4,185,042 (1980), prepared a polybutadiene
"living" polymer by anionic polymerization and then prepared a
silicon-containing 3-arm by reacting the "living" polymer with
gamma-glycidoxypropyltrimethoxysilane in Example 5.
R. Milkovich, U.S. Pat. No. 4,417,029 (1983), prepared a hydrocarbon star
polymer having 10 arms of 2 kinds. Of the 10 arms, 5 were a diblock
copolymer of polystyrene (Mn=12,300) and polyisoprene (Mn=52,450). The
other 5 arms were polyisoprene (Mn=52,450). The hydrocarbon star polymer
was prepared by charging sec-butyllithium, then styrene, them more
sec-butyllithium, then isoprene, then divinylbenzene at a mole ratio of
divinylbenzene to sec-butyllithium initiator of 5.5:1. Subsequent reaction
of the "living" lithium sites in the core with carbon dioxide or ethylene
oxide produced carboxylic acid or hydroxyl groups respectively in the core
in Example 2.
T. E. Kiovsky, U.S. Pat. No. 4,077,893 (1978), suggested reacting
lithium-terminated "living" polymers derived from diene monomers (e.g.,
butadiene or isoprene) with divinylbenzene to form a 4-25 arm star polymer
and then reacting the (still living) star polymer with the same or a
different monomer to grow further polymer chains from the core. Thus, star
polymers having two kinds of arms were proposed in Col. 5, lines 40-58.
A series of Dow Chemical patents including U.S. Pat. Nos. 4,587,329;
4,599,400; 4,468,737; 4,558,120; and 4,507,466 are directed to
hyper-branched non-acrylic stars such as of polyamide or polyether
condensation polymers with two or more ends per branch. These are
discussed in "Dendritic Macromolecules: Synthesis of Starburst
Dendrimers"--Tornalia, et al. Macromolecules 19, No. 9, 2466-2468 (1986).
W. Burchard and H. Eschway, U.S. Pat. No. 3,975,339 (1976), reacted a
mixture of 50% divinylbenzene and 50% ethylvinylbenzene in toluene with
n-butyllithium to produce a polydivinylbenzene microgel having 270 active
lithium-carbon bonds per molecule. This was subsequently reacted with
styrene to produce a star polymer having 270 arms, each arm having a
weight average molecular weight of 17,500 in Example 1.
H. Eschway, M. L. Hallensleben and W. Burchard, Die Makromolekulare Chemie,
Vol. 173, pp 235-239 (1973), describe the anionic polymerization of
divinylbenzene using butyllithium to produce soluble "living" microgels of
high molecular weight. These microgels were then used to initiate
polymerization of other monomers to produce star polymers. The number of
arms depended on the number of active sites in the "living" microgel,
which in turn depended on the mole ratio of divinylbenzene to butyllithium
initiator. To avoid gellation it was necessary to work at low
concentrations (e.g., 2.5% in benzene).
H. Eschway and W. Burchard, Polymer, Vol. 16, pp 180-184 (March, 1975),
prepared a star polymer having 67 polystyrene arms and 67 polyisoprene
arms by sequential anionic polymerization of sytrene, divinylbenzene and
isoprene. Low concentrations of monomer were used to avoid gellation.
2. Preparation of Acrylic Star Polymers
In contrast to hydrocarbon star polymers (which may be prepared having
different arm sizes, different numbers of arms and even with two different
kinds of arms attached to the same core), acrylic star polymers have been
available only in a limited variety of structures.
Although not making stars, L. R. Melby in U.S. Pat. No. 4,388,448 (June 14,
1983) does make glycidyl methacrylate polymers at low temperatures by
anionic polymerization.
G. W. Andrews and W. H. Sharkey, U.S. Pat. No. 4,351,924 (1982), prepared
acrylic star polymers having 3 or 4 hydroxyl-terminated arms by coupling
acetal-ended, "living" poly(methyl methacrylate) with
1,3,5-tris(bromomethyl)benzene or 1,2,4,5-tetrabis(bromomethyl)benzene.
O. W. Webster, U.S. Pat. Nos. 4,417,034 (Nov. 22, 1983) and 4,508,880 (Apr.
2, 1985), and W. B. Farnham and D. Y. Sogah, U.S. Pat. Nos. 4,414,372
(Nov. 8, 1983) and 4,524,196 (June 18, 1985) showed that acrylic star
polymers can be prepared via group transfer polymerization by coupling
"living" polymer with a capping agent having more than one reactive site
or by initiating polymerization with an initiator which can initiate more
than one polymer chain. Initiators that could produce acrylic star
polymers with up to 4 arms were demonstrated. See examples 5-7 of U.S.
Pat. No. 4,508,880.
I. B. Dicker, et al., U.S. Pat. No. 4,588,795 (May 13, 1986) claims a
preferred method of group transfer polymerization using oxyanion
catalysts. I. B. Dicker, et al., U.S. Pat. No. 4,622,372 (Nov. 11, 1986)
claims an improved process with enhanced catalyst longevity. C. S.
Hutchens and A. C. Shor, U.S. Ser. No. 782,257, filed Sept. 30, 1985, now
U.S. Pat. No. 4,656,226, granted Apr. 7, 1987, claims acrylic pigment
dispersant made by GTP, such as methyl methacrylate-glycidyl methacrylate
AB dispersants with functional groups added.
H. J. Spinelli, in applications U.S. Ser. Nos. 771,682; 771,683; 771,684;
771,685; and 771,686, all filed Sept. 3, 1985, teaches the preparation of
acrylic star polymers, optionally having functional groups in the cores
and/or the arms, with more or less crosslinked cores. Preferably GTP
techniques are used with arm-first, core-first, or arm-core-arm
sequencing.
The above-cited Webster, Farnham, et. al., Dicker, et al., Hutchens, et al.
and Spinelli patents and applications are incorporated herein by
reference.
The following is an update of the status of the above-mentioned
applications of Spinelli. Ser. Nos. 771,682 and 771,683 are now
respectively U.S. Pat. Nos. 4,659,782, and 4,659,783, granted Apr. 21,
1987; Ser. No. 771,684 is now U.S. Pat. No. 4,695,607 granted Sept. 22,
1987; Ser. No. 771,685 was abandoned after refiling as divisional cases
Ser. No. 914,714 and 914,715 on Sept. 30, 1986, now U.S. Pat. No.
4,794,144 and U.S. Pat. No. 4,810,756.
R. J. A. Eckert, U.S. Pat. No. 4,116,917 (1978), describing hydrocarbon
star polymers suggested that small amounts of other monomers (e.g., methyl
methacrylate) may be included (Col. 3, lines 22-28) and that ethylene
dimethacrylate may be used as a coupling agent (Col. 5, lines 22-28). A
similar suggestion is made by T. E. Kiovsky, U.S. Pat. No. 4,077,893,
cited above.
J. G. Zilliox, P. Rempp and J. Parrod, J. Polymer Sci., Part C, Polymer
Symposia No. 22, pp 145-156 (1968), describe the preparation, via anionic
polymerization, of a mixture of star polymers having 3 to 26 polymethyl
methacrylate arms attached to cores of ethylene glycol dimethacrylate. The
mixture also contained linear polymethyl methacrylate. The article says
the lengths of the individual branches were constant but that the number
of branches per star "fluctuates considerably", giving rise to a very high
polydispersity.
3. Uses of Star Polymers
Hydrocarbon star polymers have been used as additives to improve the impact
strength of polyphenylene ether resins--W. R. Haaf et al., U.S. Pat. No.
4,373,055 (1983); dry nylon--W. P. Gergen et al. U.S. Pat. No. 4,242,470
(1980); rubber-modified polystyrene--A. Aoki et al, U.S. Pat. No.
4,304,881, cited above; and chlorinated polyvinyl chloride resins M. H.
Lehr, U.S. Pat. No. 4,181,644 (1980).
Hydrocarbon star polymers have also been added to asphaltic concrete to
improve the service life--C. R. Bresson, U.S. Pat. No. 4,217,259 (1980);
to polyetherester resins to provide a desirable overall balance of
properties--R. W. Seymoure, U.S. Pat. No. 4,011,286 (1977), and to
lubricating oil to improve the viscosity index and act as a dispersant--T.
E. Kiovsky, U.S. Pat. No. 4,077,893 (1978).
Hydrocarbon star polymers have also been used to prepare thermoplastics
having good clarity by blending them with thermoplastic resins such as
methyl methacrylate/styrene/butadiene copolymers, polyester urethanes,
epoxides, acrylics, polycarbonates, polyesters, etc.,--E. L. Hillier, U.S.
Pat. No. 4,048,254 (1977).
SUMMARY OF THE INVENTION
The invention provides a hybrid star polymer which comprises
a. a crosslinked core comprising a condensation polymer, and
b. attached to the core, at least 5 arms comprising acrylic block polymer
chains with functional groups at the end of the chains which is attached
to the core.
Preferably, the invention provides a hybrid star polymer prepared by the
process wherein the functional group in the arms is an epoxy derived from
glycidyl methacrylate.
Preferably, in the arms of star polymers of the invention, the monomers
having one carbon-carbon double bond polymerizable by a group transfer
polymerization process are selected from
##STR1##
and mixtures thereof wherein:
X is --CN, --CH.dbd.CHC(O)X' or --C(O)X';
Y is --H, --CH.sub.3, --CN or --CO.sub.2 R, provided, however, when X is
--CH.dbd.CHC(O)X', Y is --H or --CH.sub.3 ;
X' is OSi(R.sup.1).sub.3, --R, --OR or --NR'R"; each R.sup.1 is
independently selected from C.sub.1-10 alkyl and C.sub.6-10 aryl or
alkaryl;
R is C.sub.1-20 alkyl, alkenyl, or alkadienyl; C.sub.6-20 cycloalkyl, aryl,
alkaryl or aralkyl; any of said groups containing one or more ether oxygen
atoms within aliphatic segments thereof; and any of all the aforesaid
groups containing one or more functional substituents that are unreactive
under polymerizing conditions; and each of R' and R" is independently
selected from C.sub.1-4 alkyl.
More preferably, hydrid star polymers of the invention as they are being
made comprise
a. a core comprising a polymer derived from condensation polymerization of
functional groups on arms, with or without other monomers
b. attached to the core, at least 5 arms comprising polymer chains derived
from one or more monomers polymerizable by an initiator, Q--Z, and
c. attached to the core and/or to at least some of the arms the groups
Q--Z"--,
where the group Q-- is the initiating moiety in a "living" group transfer
polymerization initiator, Q--Z, and where the group Z"-- is derived from
an activating substituent, Z, of a group transfer polymerization
initiator, Q--Z, and where the initiator, Q--Z, is capable of reacting
with a monomer having carbon-carbon double bonds to form a "living"
polymer chain having the group, Z"--, attached to one end of the "living"
polymer chain and the group, --O--, attached to the other, "living", end
of the "living" polymer chain and where, the "living" polymer chain is
capable of initiating polymerization of additional monomer, which can be
the same or different from the monomer used to prepare the "living"
polymer chain, to produce a larger "living" polymer chain having a group,
Z"--, attached to one end of the "living" polymers chain and the group,
Q--, attached to the other "living" end of the "living" polymer chain, and
where the group, Z"--, is the same as or an isomer of the group, Z--. As
is known in group transfer polymerization, upon quenching, such as with
water or alcohol, the Q-initiating moiety is removed and the polymer is no
longer "living".
Also preferably in the preparation of star polymers of the invention, the
"living" group transfer polymerization sites are (R.sup.1).sub.3 M--
wherein: R.sup.1 is selected from C.sub.1-10 alkyl and C.sub.6-10 aryl or
alkaryl; and M is Si, Sn, or Ge.
Still more preferably, in polymer of the invention, the group, Q--, is
(R.sup.1).sub.3 M-- as defined above.
In such polymers, the group, Z--, is selected from
##STR2##
and mixtures thereof wherein:
X' is OSi(R.sup.1).sub.3, --R, --OR or --NR'R"; each R.sup.1 is
independently selected from C.sub.1-10 alkyl and C.sub.6-10 aryl or
alkaryl;
R is C.sub.1-20 alkyl, alkenyl, or alkadienyl; C.sub.6-20 cycloalkyl, aryl,
alkaryl or aralkyl; any of said groups containing one or more ether oxygen
atoms within aliphatic segments thereof; and any of all the aforesaid
groups containing one or more functional substituents that are unreactive
under polymerizing conditions; and
each of R' and R" is independently selected from C.sub.1-4 alkyl
each of R.sup.2 and R.sup.3 is independently selected from H; C.sub.1-10
alkyl and alkenyl; C.sub.6-10 aryl, alkaryl, and aralkyl; any of said
groups except H containing one or more ether oxygen atoms within aliphatic
segments thereof; and any of all the aforesaid groups except H containing
one or more functional substituents that are unreactive under polymerizing
conditions; and
Z' is O or NR';
m is 2, 3 or 4;
n is 3, 4 or 5.
DETAILED DESCRIPTION OF THE INVENTION
To make hybrid star polymers one first prepares acrylic arms by using a
functional block copolymer prepared by GTP (e.g., epoxy block copolymers
and the wide-variety of other functional blocks that can be derived from
them) and then prepare a crosslinked, non-acrylic core by using some type
of condensation crosslinking reaction involving the functional segment of
the starting GTP block copolymer. The self-stabilized particle which is
thus produced has acrylic arms and a condensation core (hence the name
"hybrid") as opposed to stabilized particles which have acrylic arms and
acrylic cores.
The differences between all-acrylic stars and these hybrid stars involve
differences which are primarily associated with the condensation core. The
condensation core obtained in the hybrid process is generally more polar
than that produced in the all-acrylic process. Thus the swelling of the
core or the sensitivity of the core to changes in solvent composition
might take on characteristics resembling solvent-responsive dispersants.
This aspect could be important in using these solubility difference to
control particle size during synthesis and perhaps properties such as
refractive index after the particle was made or hardness and softness of
the core depending on its crosslink density. The hardness/softness of the
core might have a tremendous effect on impact resistance and toughness
especially when these hybrid stars are used in various types of acrylic
and non-acrylic plastics.
The size, polarity and hardness of the condensation core could probably be
fairly well controlled by controlling the size of the starting functional
segment together with the amount, type and functionality of the
crosslinker which is used. The ability to use a previously isolated and
characterized functional block copolymer as the starting material for a
hybrid star could be an advantage in that control over the final
stabilized particle would not rely on the existence of a "living"
non-isolated intermediate (e.g., attached and unattached arms). The
sequential nature of the process--production of the functional block
copolymer first followed by formation of the stabilized particle--is
important, however, it would not be necessary to isolate the starting
functional block copolymer in order to prepare a hybrid star, but
isolation may sometimes provide an advantage.
The nature and composition of the hybrid arms can be controlled using the
same techniques that are used for preparing the non-functional segment of
the functional block copolymers or for the preparation of arms for
all-acrylic stars.
Known uses of hydrocarbon stars together with the uses of all-acrylic stars
would all be appropriate uses for hybrid stars with particular emphasis on
the ability to vary the particle size, polarity and energy-absorbing
nature (hardness/softness) of the condensation core.
In the preparation of the arms for hybrid star polymers, use is made of
group transfer polymerization. By group transfer polymerization, is meant
a polymerization process in which polymerization of monomers having
carbon-carbon double bonds is initiated by certain initiators of the
formula Q--Z where Z is an activating substituent that becomes attached to
one end of the growing polymer molecule and where Q is a group that
continuously transfers to the other end of the growing polymer molecule as
more monomer is added to the growing polymer molecule. Thus,
polymerization of the monomer,
##STR3##
initiated by a group transfer initiator, Q--Z, proceeds as follows:
##STR4##
The group, Q, is thus an active site that can initiate further
polymerization of more monomer. The polymer molecule having the group, Q,
is referred to as a "living" polymer and the group, Q, is referred to as a
"living" group transfer initiating site.
The word "living" is used sometimes herein in quotation marks to indicate
its special meaning and to distinguish it from substances which are alive
in a biological sense.
More particularly, in the preparation of the star polymers, use is made of
the group transfer polymerization process of the general type described in
part by W. B. Farnham and D. Y. Sogah, U.S. Pat. No. 4,414,372 and by O.
W. Webster, U.S. Pat. No. 4,417,034, and in continuation-in-part U.S. Pat.
Nos. 4,508,880 Webster, granted Apr. 2, 1985, and 4,524,196 Farnham and
Sogah, granted June 18, 1985, the disclosures of all of which are
incoporated herein by reference. Group transfer polymerization produces a
"living polymer" when an initiator or the formula (R.sup.1).sub.3 MZ is
used to initiate polymerization of a monomer having a carbon-carbon double
bond.
In the initiator, (R.sup.1).sub.3 MZ, the Z group is an activating
substituent that becomes attached to one end of the "living" polymer
molecule. The (R.sup.1).sub.3 M group becomes attached to the other
("living") end of the "living" polymer molecule. The resulting "living"
polymer molecule can then itself act as an initiator for polymerization of
the same or a different monomer to produce a new "living" polymer molecule
having the Z activating substituent at one end and the (R.sup.1).sub.3 M
group at the other ("living") end. The "living" polymer may then be
deactivated, if desired, by contacting it with an active proton source
such as an alcohol. At this point, it might be useful to consider a
specific example--the group transfer polymerization of a specific monomer
(in this case, methyl methacrylate) using a specific group transfer
initiator (in this case 1-trimethylsiloxy-1-isobutoxy-2-methylpropene).
The reaction of 1 mole of initiator with n moles of monomer produces
"living" polymer as follows:
##STR5##
The
##STR6##
group shown on the left side of the "living" polymer molecule is derived
from the activating group, Z, which, in the initiator, was in the form
##STR7##
The --Si(CH.sub.3).sub.3 group on the right side ("living" end) of the
"living" polymer molecule is the (R.sup.1).sub.3 M group. The "living"
polymer molecule can act as an initiator to initiate polymerization of the
same or a different monomer. Thus, if the above "living" polymer is
contacted with m moles of butyl methacrylate in the presence of active
catalyst, the following "living" polymer is obtained:
##STR8##
If the resulting "living" polymer is then contacted with methanol, the
following deactivated polymer is obtained.
##STR9##
Preferably, group transfer polymerization procedures used in this invention
involve a catalyst and an initiator and optionally a polymerization life
enhancer. The preferred process involves contacting under polymerization
conditions at least one polar monomer with (i) a polymerization initiator
compound comprising a tetracoordinate metal selected from Si, Ge and Sn
having at least one activating substituent or activating diradical
attached thereto and optionally having one or more substituents that are
inert under polymerizing conditions, (ii) a catalyst which is a salt
comprising an oxyanion whose conjugate acid has a pKa (DMSO) of about 5 to
about 24, and a suitable cation, and (iii) a polymerization life
enhancement agent which retards the availability of said catalyst during
polymerization so as to enhance the duration of "livingness" of the
polymerization by increasing the proportion of polymerization events to
termination events. Optionally, the catalyst can be a source of fluoride,
bifluoride, cyanide, or azide ions or a suitable Lewis acid.
In the preferred method of the invention, a "living" polymer (the arm) is
prepared by contacting a monomer having functional groups and a
carbon-carbon double bond with a group transfer initiator, (R.sup.1).sub.3
MZ. The resulting "living" polymer is then quenched with water or an
active hydrogen-containing compound, and then reacted by a condensation
reaction of the functional groups in the arms, with or without other
monomers, to form a crosslinked core.
INTRODUCTION TO EXAMPLES
Conceptually, the synthesis of hybrid stars is based upon the prior
synthesis of functional block copolymers followed by crosslinking of the
functional segment with the appropriate crosslinking agent. Some examples
of functional segments and potential crosslinking agents are listed below:
______________________________________
Functional Potential
Segments Crosslinkers
______________________________________
Epoxides* Diacids e.g.,
oxalic
adipic
pthalic
Anhydrides e.g.,
pthalic
maleic
Diamines e.g.,
hydrazine
ethylenediamine
1,3-diaminopropane
1,4-diaminobutane
1,6-hexamethylene diamine
isophorone diamine
Diphenols e.g.,
bisphenol A
Strong Proton acids
para toluene sulfonic acid (pTSA)
Trifluoro acetic acid
Lewis Acids
Boron trifluoride etherate
Hindered Amines, e.g.,
diazo bicyclo octane (DABCO)
Amines
obtained from Dieppoxides e.g.,
epoxy block diglycidyl ethers
copolymers by Epon epoxy resins from Shell
ammoniation Chemical
Di/Multi acrylates, e.g.,
Trimethyolpropane triacrylate
ethlyene glycol diacrylate
butane diol diacrylate
Di/Multi isocyanates, e.g.,
isophrone diisocyanate
Desmodur N from Bayer
1,6 hexamethylene diisocyanate
Melamines
Diacids/Anhydrides
Dialdehydes/diketones
Acid and Azirdinyl
acid functional Diepoxide
blocks made Polyepoxide
from masked Polyaziridine
acid monomers
or from functional initiators
aziridinyl- Polyacid
containing
methacrylates
Alcohols
hydroxy terminated
Melamines
acrylicmade using
functional initiators
Di/multi isocyanates
hydroxy functional
blocks made from Dialdehydes/Diketones
epoxy blocks by
hydrolysis Diacids/anhydrides
______________________________________
*Essentially any crosslinking agent for epoxides will probably work to
some extent. In the case of proton and Lewis acidpromoted crosslinking a
nonpolar solvent, e.g., toluene free of any protonatable or complexing
impurities, e.g., glymes may be necessary.)
Other ingredients and procedures which were used in the examples and in
practicing the invention are outlined below to aid in understanding.
I. Starting Materials
A. Initiators
Isobutyl Initiator
1-trimethylsiloxy-1-isobutoxy-2-methylpropene
##STR10##
Molecular weight: 216.39 OH-Blocked Initiator
1-(2-trimethylsiloxyethoxy)-1-trimethylsiloxy-2-methylpropene
##STR11##
Molecular Weight: 276.52 B. Catalysts
TASHF.sub.2
Tris(dimethylamino)sulfonium bifluoride
##STR12##
TBAHF.sub.2 Tetrabutylammonium bifluoride
(C.sub.4 H.sub.9).sub.4 N.sup..sym. HF.sub.2.sup..crclbar.
TBACB
Tetrabutylammonium chlorobenzoate
C. Solvents
Glyme
1,2-dimethoxyethane
CH.sub.3 OCH.sub.2 CH.sub.2 OCH.sub.3
Others
Acetonitrile=CH.sub.3 CN
Xylene
THF=Tetrahydrofuran=
##STR13##
D. Monomers MMA
methyl methacrylate
##STR14##
M.W.=100.12 2EHMA
2-ethylhexyl methacrylate
##STR15##
M.W.=198.29 II. Reactions
A. Polymerization of MMA with "Isobutyl Initiator "
##STR16##
B. Polymerization of MMA with "OH-Blocked Initiator"
##STR17##
The arms prepared in Examples 1-2, and other similar arms, can be use as
the GTP-functional arms for the reactions of Examples 3-5.
In the examples and elsewhere, parts, percentages and proportions are given
by weight except where indicated otherwise.
EXAMPLE 1
Preparation of MMA/BMA//GMA (D.sub.p -40//D.sub.p -4)
All monomers and solvents were dried by passing over 4A molecular sieves. A
250 mL round bottom 4-necked flask equipped with condenser, thermoprobe,
N.sub.2 inlet, mechanical stirrer and was charge with 44.1 g glyme, 1.68 g
of 1-trimethylsiloxy-1-isobutoxy-2-methyl propene, and 66 microliter of a
1M solution of tetrabutyl ammonium m-chlorobenzoate in acetonitrile. A
feed containing 33 microliter of 1M tetrabutyl ammonium m-chlorobenzoate
in acetonitrile diluted into 0.2 mL of glyme was added over 90 minutes.
Concurrently a second feed containing MMA (13.2 g) and BMA (18.8 g) was
added over 30 minutes. The temperature rose to 54.4.degree. C. After
completion of the 30 minute feed, the batch was cooled to 5.degree. C. and
GMA (3.74 g, was added over 2 minutes. The reaction mixture was kept at
<10.degree. C. until feed 1 was completed. Xylene (0.1 g) and methanol
(1.1 g) were added over 15 minutes. M.sub.n =6630, d=1.16 Theoretical
M.sub.n =5400 solids=43.8% Epoxy titration=0.32 meq/g solution.
EXAMPLE 2
Preparation of MMA//GMA 87//13 Block Copolymer
A 250 mL four neck roundbottom flask was equipped with septa, thermoprobe
and glass paddle stirrer. Flask was then evacuated and dried with heat
gun. After filling the flask with nitrogen, glyme (95.5 g) and
dimethylketene isobutyl trimethylsilylacetal (2.4 g, 11.1 m moles) were
added by syringe. To this mixture a catalyst solution (0.05 cc, 1 m cesium
bifluoride in acetonitrile) was also added by syringe. A catalyst feed
(0.02 cc, 1 m cesium bifluoride in acetonitrile, in 3 cc glyme) and an MMA
monomer feed (40.0 g, 0.4 m) were added simultaneously by syringe pump.
During the MMA feed a maximum temperature of 54.2.degree. C. was observed
(feed started at 23.9.degree. C.). After completing the MMA feed (45 min)
batch was cooled to 2.5.degree. C. with ice bath and 6.0 g (0.42 m) of GMA
was then added all at once by dropping funnel. Batch temperature increased
to 12.degree. C. after GMA addition (exotherm) and then cooled to
6.degree. C. after a few minutes. Catalyst feed solution was maintained
for an additional 15 min. (100 min total feed time). Batch was stirred an
additional 90 min. with ice bath removed and quenched with 5.0 g of
methanol.
______________________________________
Analytic Results
______________________________________
Residual Monomer:
GMA - less than 1%
MMA - less than 1%
by high pressure
liquid chromatography
(HPLC)
GPC mol. wt. M.sub.n 4770 calculated 4180
Polydispersity (M.sub.w /M.sub.n) = 1.3
______________________________________
Epoxy D.sub.p (by titration) = 3.0 (theoretical = 3.8) WT. % solids = 49%
EXAMPLE 3
Reaction of Epoxy Block Copolymer With Isophorone Diamine
A 250 mL threeneck roundbottom flask was equipped with an addition funnel,
thermocouple and a mechanical stirrer. The flask was charged with toluene
(25.0 g) and isophorone diamine (1.5 g, 0.019M). The addition funnel was
charged with a solution of epoxy block copolymer such as that of Example 1
or 2 in toluene; 48.5% solids--24.4 g polymer, 0.019M epoxy) and
additional toluene (50 g). Over a 30 min interval the epoxy resin solution
was added dropwise to the diamine solution. A small temperature rise (from
25.degree. C. to about 29.degree. C.) was observed. After standing for
about three hours the originally clear pale-yellow solution was observed
to take on a hazy, blueish tinge and a small amount of precipitate was
observed.
EXAMPLE 4
Reaction Of Epoxy Block Copolymer With 1,6-Hexanediamine
A 250 mL threeneck roundbottom flask was equipped with an addition funnel,
themocouple and a mechanical stirrer. The flask was charged with a
solution of an epoxy block copolymer in toluene; 49.5 g of a 47.4% solids
solution, 23.5 g polymer, 0.054M epoxy) and additional toluene (25.0 mL).
A solution of 1,6-Hexanediamine (6.3 g, 0.054M, 2eq amine) in glyme (25.0
g) was added dropwise from the addition funnel over 30 min. During the
addition interval a 2.degree. C. temperature rise was observed. After
holding for about 2 hrs the clear solution became pale-yellow in color and
a small amount of precipitate was observed.
EXAMPLE 5
Reaction Of An Epoxy Block Copolymer With Trifluoroacetic Acid
A 250 mL threeneck roundbottom flask was equipped with an addition funnel,
thermocouple and a mechanical stirrer. The flask was charged with a
toluene solution of a BMA//GMA epoxy block copolymer (51.3 g), and
additional toluene (21.0 g). Trifluoroacetic acid (0.3 g) was added via
syringe and the mixture was heated at reflux for about two hours. After
cooling, the mixture had a yellow-orange color with a slight haze. The
viscosity was higher than at the start of the reaction. There were no gel
particles observed. GPC suggested that between 25-30% of the material had
a molecular weight (Mn) of about 10,000,000 with a polydispersity index of
only 2.2.
An additional experiment involving a toluene solution of a BMA//GMA epoxy
block copolymer; 83.5 g) and trifluoroacetic acid (0.5 g) showed a
3.degree. C. temperature rise on addition of the acid and resulted in a
hazy solution which had an opalescent blue tinge. An experiment involving
an MMA//GMA epoxy block copolymer; 20.0 g of solid polymer in 60.0 g
toluene) with trifluoroacetic acid (0.2 g) showed a 1.degree. C.
temperature rise, but afforded a clear polymer solution.
EXAMPLE 6
Preparation of Hydroxyl Containing Polymer
A 250 mL flask is charged with toluene, 43.7 gm, TFH, 43.5 gm,
1-trimethylsiloxy-1-methoxy-2-methyl propene, 1.0 gm (0.0057M),
2-trimethylsiloxyethyl methacrylate, 9.31 gm. The catalyst
tetrabutylammonium meta-chlorobenzoate, 0.05 ml of a 1.0M solution in
acetonitrile, is then added and an exotherm results. Feed I,
[tetrabutylammonium meta-chlorobenzoate, 0.05 ml of a 1.0M solution in
acetonitrile, and THF, 4.4 gm] is started and added over a period of 100
minutes. Feed II [methyl methacrylate, 51.8 gm] is started 40 minutes
after the initial shot of catalyst is added to the flask and is then fed
in over 40 minutes. At 160 minutes water, 3.9 gm, and isopropanol, 16.3
gm, are added and then heated to reflux for 1 hour. A linear block polymer
is formed. Its composition is methyl methacrylate//hydroxyethyl
methacrylate 89.6//10.4. Its molecular weight is Mn=17,000, Mw=26,800.
EXAMPLE 7
Reaction of Hydroxyl Polymer with a Diisocyanate
A 250 mL flask is charged with toluene, 30.0 gm, and polymer of Example 6,
58.61 gm. The flask is heated to reflux and 36.6 gm of solvent are
removed. Trimethylhexamethylene diisocyanate, 1.75 gm, dibutyltin
dilaurate, 4 drops of a 1% solution in toluene, and toluene, 60.0 gm, are
added and heated to reflux for 30 minutes. A hybrid star polymer results.
Its molecular weight is Mn=34,400 and Mw=64,100.
Industrial Applicability
In addition to the uses of hybrid star polymers of the invention in
coatings for various uses such as solvent responsive dispersants and as
tougheners for plastic sheeting and in the other applications indicated
above, such hybrid star polymers have many other potential uses, as do
other products made by group transfer polymerization. These can include
cast, blown, spun or sprayed applications in fiber, film, sheet, composite
materials, multilayer coatings, photopolymerizable materials,
photoresists, surface active agents including soil repellants and
physiologically active surfaces, adhesives, adhesion promoters and
coupling agents, among others. Uses include as dispersing agents, rheology
control additives, heat distortion temperature modifiers, impact
modifiers, reinforcing additives, stiffening modifiers and applications
which also take advantage of narrow molecular weight and low bimodal
polydispersity. End products taking advantage of available characteristics
can include lacquers, enamels, electrocoat finishes, high solids finishes,
aqueous or solvent based finishes, clear or filled acrylic sheet or
castings, including automotive and architectural glazing and illumination
housings and refractors, additives for oil and fuel, including antimisting
agents, outdoor and indoor graphics including signs and billboards and
traffic control devices, reprographic products, and many others.
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