Note: Descriptions are shown in the official language in which they were submitted.
- 21~7303
I
-
CATIONIC POLYMERIZATION IN CARBON DIOXIDE
Related Al~plications
This is a continuation-in-part application of
- copending U.S. Application Serial No. 08/292,424, filed
18 August 1994.
sField of the Invention
The present invention relates to the
polymerization of a monomers, and more specifically
relates to the cationic polymerization of monomers in
carbon dioxide.
10Back~round of the Invention
Prior to about 1984, cationic polymerizations
which proceed through a carbenium ion were believed to be
uncontrollable due to the high reactivity of the
carbenium ion. Efforts have been expended to determine
counteranion, temperature and solvent conditions which
will permit the living polymerization of various monomer
systems. The term "cationic" polymerization as used
herein refers to a positively charged (cationic) polymer
chain resulting from the reaction of an initiator with a
monomer.
Proper selection of initiators for cationic
polymerization is essential to the generation of
polymers. The proper selection of the cationic
polymerization initiator in turn depends upon the monomer
to be polymerized. Kennedy et al., Polymer Bulletin
15:317 (1986), reported the cationic polymerization of
2~ 97303
'
isobutylene using an initiating system including boron
trichloride with tertiary esters in chloromethane,
methylene chloride, chloroethane, and mixtures of
chlorinated solvents in n-hexane. Hagashimura et al.,
Macromolecules 22(3) :1009 (1989), proposes the cationic
polymerization of vinyl ethers using a weak nucleophile
and a Lewis base deactivator in a solution of n-hexane.
Nevertheless, there remains a need in the art for a
method of cationically polymerizing a variety of monomers
while controlling the characteristics of the polymer
produced.
In view of the foregoing, it is a first object
of the present invention to provide a method of
cationically polymerizing monomers in an environmentally
sound. solvent, while controlling the particle size and
morphology of the polymer produced.
Summary of the Invention
The present invention provides a method of
carrying out the cationic polymerization of a monomer in
carbon dioxide. The method includes the steps of (a)
providing a reaction mixture comprising carbon dioxide,
a monomer, a catalyst and a cationic polymerization
initiator, wherein the cationic polymerization initiator
is capable of initiating the cationic polymerization of
the monomer; and (b) polymerizing the monomer in the
reaction mixture to form a polymer.
Carbon dioxide as a polymerization solvent
medium provides a number of significant advantages to
polymerization systems. Traditionally, cationic
polymerization were conducted in a dry, inert solution
dispersing medium; typically an organic solvent or a
chlorinated organic solvent. Herein we describe an
environmentally sound solvent alternative for cationic
polymerization, namely, carbon dioxide. In addition, the
polymer can be easily isolated from the carbon dioxide
21 97303
-
solvent (i.e. the continuous phase) at the termination of
polymerization, as the carbon dioxide can simply be
vented from the reaction vessel. Second, the density and
viscosity of carbon dioxide can be tuned over a large
range of conditions due to its compressibility,
particularly in the supercritical phase, and thus the
particle size and morphology of the polymer may be
controlled.
U.S. Patent No. 5,312,882 to DeSimone et al.
discloses the use of supercritical carbon dioxide as a
suitable solvent for heterogeneous polymerization of
hydrophobic monomers. In addition, PCT Patent
Application No. PCT/US93/01626 (W093-20116) discloses the
use of supercritical carbon dioxide as a suitable solvent
for the homogeneous polymerization of fluoromonomers as
well.
The foregoing and other objects and aspects of
the present invention are explained in detail in the
specification set forth below.
Detailed Descril~tion of the Invention
Cationic polymerizations of the present
invention may take place heterogeneously or
homogeneously. The term "heterogeneous polymerization"
as used herein refers to a polymerization carried out
through the use of media that create at least two
separate phases (i.e., a continuous phase and a dispersed
phase). In contrast, the term "homogeneous
polymerization" as used herein refers to a polymerization
reaction carried out through the use of media which do
not create more than one phase, and which are identified
by being optically transparent. Heterogenous
polymerizations include suspension polymerizations in
which an initiator is solubilized in the dispersed phase,
emulsion polymerizations in which an initiator is
solubilized in the continuous phase, and dispersion and
precipitation polymerizations which are initially
21 97303
.
homogeneous polymerization reactions but which nucleate
particles precipitate out of solution to form a
heterogeneous polymerization.
The present invention is directed to a method
of carrying out the cationic polymerization of a variety
of monomers in carbon dioxide. The method comprises (a)
providing a reaction mixture comprising carbon dioxide,
one or more monomers, a catalyst and a cationic
polymerization initiator, wherein the cationic
polymerization initiator is capable of initiating the
cationic polymerization of the monomer(s), and (b)
polymerizing the monomer(s) in the reaction mixture.
The carbon dioxide can be employed in a liquid,
vapor, or supercritical phase. As used herein,
"supercritical" means that a fluid medium is at a
temperature that is sufficiently high that it cannot be
liquified by pressure. The thermodynamic properties of
carbon dioxide are reported in Hyatt, ~. Org. Chem.
49:5097 (1984); therein, it is stated that the critical
temperature of carbon dioxide is about 31~C. If liquid
carbon dioxide -is employed, the temperature of the
reaction will be below 31~C. Preferably, the carbon
dioxide is in a liquid phase. The reaction temperature
should be chosen to provide sufficient heat energy to
initiate and propagate the polymerization, without
leading to unwanted side reactions. Preferably, the
reaction temperature will be between -50~C and 200~C, and
most preferably between -50~C and 31~C.
A wide variety of monomers may be employed in
the method of the instant invention. The method may be
employed for the polymerization of a single monomer or
the copolymerization or block polymerization of two or
more monomers. Monomers may be substituted or
unsubstituted, saturated or unsaturated, linear or
branched, cyclic or aromatic. The selection of monomer
or monomers to be employed will affect the choice of
'- 2197303
~ appropriate cationic polymerization initiators, as
discussed below.
Suitable monomers may be selected from a wide
variety of monomers which are known to those skilled in
the art as capable of undergoing cationic polymerization.
Some exemplary monomers include vinyl ether monomers,
cyclic ether monomers, oxazoline monomers, hydrocarbon
olefin monomers, cyclic carbonate monomers, and
formaldehyde. In addition, diene comonomers may be
employed in copolymerization systems.
Suitable vinyl ether monomers include alkyl vinyl
ethers such as methyl vinyl ether and isobutyl vinyl
- ether.
Suitable cyclic ether monomers include alkyl,
alkoxy, and halo substituted cyclic ethers having a
general formula selected from the group consisting of
2 0 Rl
wherein R1.and R2 are independently selected from the
group consisting of H, alkyl and preferably C1-C8 alkyl,
haloalkylalkoxymethyl of the formula (CH20(cH2)mcxF2x~l)
wherein m is 1-3 and x is 1-8, amine, amide, and
alkylhaloamine of the formula (CH2)zNF2 wherein z is 1-3,
and n is a number from 1 to 2 r and wherein R7 and R8 are
indepdently selected from the group consisting of alkyl;
akloxy; haioalkylalkoxymethyl of the formula
(CH2O (cH2) mcxF2x~l); azido of the formula CH2N3; alkylhalo of
the formula CH2halo wherein halo is F~ Cl~ Br, or I;
alkylhydroxy; and alkylalkoxy. Suitable cyclic ether
monomers for use in the instant invention include 3,3-
(bisethoxymethyl)oxetane, 3-(1',1'-
dihydroheptafluorobutoxymethyl)-3-methyloxetane,
Substitute Page
2197303
.
-5/1-
tetrahydrofuran, trioxane, ethylene oxide. Cyclic ethers
have previously been cationically polymerized in
nitromethane, methylene chloride, ethylene chloride,
carbon tetrachloride, and halogenated aromatic
hydrocarbons. See, U. S. Patent No. 4,393,199 to Manser,
and E. Goethals, Makromol. Chem., Macromol. Symp 42/43 :51
Substitute Pago
21 97303
.
(1991) the disclosure of which is incorporated herein by
reference in its entirety. The cyclic ether monomers can
be prepared using conventional methods known to those
skilled in the art, such as the methods described in U.S.
Patent No. 5,210,153 to Manser et al., and H. Mark, et
al., Encyclo~edia of Polymer Science and Enqineerinq, 2d
ed. 10:654 (1985), the disclosures of which are
incorporated herein by reference in their entirety.
Suitable oxazoline monomers include alkyl,
alkoxy, and halo substituted oxazolines having a general
formula
<O
R~
wherein R3 and R4 are independently selected from the
group consisting of H, alkyl and preferably C1-C8 alkyl,
alkoxy and preferably C1-Cg alkoxy, haloalkylalkoxy of the
formula (CH2O(CH2)mCXF2x~l) wherein m is 1-3 and x is 1-8,
amine, amide, and alkylhaloamine of the formula (CH2)zNF2
wherein z is 1-3, and n is a number from 1 to 5.
Exemplary cyclic ether monomers for use in the instant
invention include 2-ethyl oxazoline, 2-methyl oxazoline,
2-(1,1,2,2-tetrahydroperfluorooctane~ oxazoline.
Suitable hydrocarbon olefin monomers include
substituted or unsubstituted styrene, such as p-methoxy
styrene and alkylene monomers such as isobutylene and
propene.
Suitable cyclic carbonate monomers include
compounds having the formula
- 2~ q7303
-
o o
l~ J
R5/ R~,
wherein Rs and R6 are independently selected from the
group consisting of H, alkyl and preferably C1-C8 alkyl,
alkoxy and preferably C1-C9 alkoxy, and haloalkylalkoxy of
the formula (CH2O(CH2)mCXF2x~l) wherein m is 1-3 and x is 1-
8.
Suitable diene comonomers include butadiene,
and isoprene.
The cationic polymerization is typically
catalyzed by the addition of one or more cationic
polymerization catalysts. The catalysts may be provided
independently of the other reactants, or may be premixed
or coupled with the initiator. Suitable catalysts will
depend upon the particular polymerization system (i.e.,
monomer(s) and initiator) to be polymerization.
Suitable cationic polymerization catalysts for
the polymerization of vinyl ether monomers include ethyl
aluminum dichloride. According to one preferred
embodiment, the ethyl aluminum dichloride catalyst and
the initiator are provided in the reaction in the form of
a catalyst/initiator couple. Preferably, the catalyst
and initiator are premixed and coupled prior to reaction
with the vinyl ether monomer.
Suitable cationic polymerization catalysts for
the polymerization of cyclic ethers and oxazolines
include boron trifluoride tetrahydrofuranoate.
Suitable cationic polymerization catalysts for
the polymerization of hydrocarbon olefins include tin
tetrachloride, titanium tetrachloride, boron trichloride,
boron trifluoride.
- ?197303
. . ;
~ .
--8--
Suitable cationic polymerization catalysts for the
polymerization of cyclic carbonates and formaldehyde
include boron trifluoride.
The polymerization is initiated by the addition of a
cationic polymerization initiator. The selection of a
suitable cationic polymerization initiator will
necessarily depend upon the monomer or monomers to be
polymerized, and their compatibility with carbon dioxide.
The polymerization of vinyl ether monomers is typically
initiated by the addition of a cationic polymerization
initiator comprising an ester initiator and a Lewis base
deactivator. The ester initiator comprises an adduct of
- acetic acid and isobutyl vinyl ether. Suitable Lewis
base deactivators include ethyl acetate.
The polymerization of cyclic ether monomers is
typically initiated by the addition of a cationic
polymerization initiator comprising a strong acid or a
Lewis acid, and optionally also a preinitiator.
Exemplary strong acids for use in as cationic
polymerization initiators of cyclic ethers include
triflic acid. Suitable Lewis acid initiators include
boron trifluoride. Suitable preinitiators include water,
alcohols, ethers and esters. One preferred preinitiator
is butanediol.
The polymerization of oxazoline monomers is
typically initiated by the addition of a cationic
polymerization initiator comprising a strong acid or a
Lewis acid, and optionally also a preinitiator.
Exemplary strong acids and Lewis acids are described
above. In addition, preinitiators such as those
described above may be included.
The polymerization of hydrocarbon olefin monomers is
typically polymerized by the catalyst described above
together with a cationic polymerization initiator
selected from the group consisting of l-chloro-1-phenyl
ethane, 2-chloro-2,4,4-trimethylpentane, tertiary ethers,
Lewis bases, or 2-methoxy-2-propyl benzene. Suitable
Substitute Page
- 2:1 97303
;
-8/1-
Lewis bases include dimethyl sulfoxide, acetamide, or
ethyl acetate. The
Substitute Page
21 97303
-
initiator may also comprise a deactivator, such as
tetrabutylammonium chloride or the like. Accordingly to
one preferred embodiment, styrene is cationically
polymerized using 1-chloro-1-phenyl ethane and
tetrabutylammonium chloride as the initiator. According
to a second preferred embodiment, isobutylene is
cationically polymerized using 2-chloro-2,4,4-
trimethylpentane as the initiator.
The polymerization of cyclic carbonate monomers
is typically initiated by the addition of a cationic
polymerization initiator comprising methyl triflate,
methyl iodide, or benzyl bromide. The use of these
initiators in the cationic polymerization of cyclic
carbonate monomers in methylene chloride was previously
reported in T. Endo, et al., J. of Poly. Sci. :Part
A:Poly. Chem., 31:581 (1993) the disclosure of which is
incorporated herein by reference in its entirety.
The polymerization of formaldehyde is typically
initiated by the addition of a cationic polymerization
initiator comprising strong acids or Lewis acids and a
preinitiator. One suitable strong acid is hydrochloric
acid. A suitable Lewis acid is boron trifluoride. A
suitable preinitiator is water. The use of this
initiator system was previously reported in M. Stevens
PolYmer ChemistrY, 2nd ed., Oxford University Press, 355-
366 (1990), the disclosure of which is incorporated
herein by reference in its entirety for the
polymerization of formaldehyde in hydrocarbon solvents.
The reaction mixture may be homogeneous or
heterogeneous depending upon the monomer or monomers to
be polymerized. In some cases, the polymerization is a
dispersion polymerization meaning that the reaction
mixture may initially be homogeneous and becomes
heterogeneous as the polymer nucleates a particle which
is not soluble in the solvent.
The polymerization reaction mixture may include
other additives and reactants known to those skilled in
21 973~3
'
-10 -
the art. For example in one preferred embodiment, the
process of the invention includes the addition of
surfactant for stabilizing the monomer and polymer in the
polymerization medium. The surfactant should be one that
is surface active in carbon dioxide and thus partitions
itself at the carbon dioxide-monomer interface. Suitable
surfactants are described in detail in U.S. Patent No.
5,312,882 to DeSimone et al., the disclosure of which is
incorporated herein by reference in its entirety. Such
a surfactant should lower the interfacial tension between
the carbon dioxide polymerization medium and the polymer,
and thus create a dispersed phase. The surfactant is
generally present in the reaction mixture in a
concentration of from about 0.001 up to about 30 percent
by weight. The surfactants can be nonreactive in the
polymerization or can react with and thereby be included
with the forming polymer. See, e. g., U . S . Pat. Nos.
4,592,933 and 4,429,666 for exemplary reactive
surfactants.
The surfactant should contain a segment that is
soluble or interfacially active in carbon dioxide ("CO2-
philic"). Exemplary CO2-philic segments include a
fluorine-containing segment, such as can be found in
fluoropolymers or copolymers of fluoropolymers, or a
siloxane-containing segment, such as can be found in
siloxane polymers or copolymers of siloxane polymers. As
used herein, a "fluoropolymer" has its conventional
meaning in the art. Exemplary fluoropolymers are those
formed from: fluoroacrylate monomers such as 2-(N-
ethylperfluorooctanesulfonamido) ethyl acrylate ("Et-
FOSEA"), 2-(N-ethylperfluorooctanesulfonamido) ethyl
m e t h a c r y l a t e ( " E t F O S E M A " ) , 2 - ( N -
methylperfluorooctanesulfonamido) ethyl acrylate
("MeFOSEA"),2-(N-methylperfluorooctanesulfonamido) ethyl
methacrylate ("MeFOSEMA"), 1,1-Dihydroperfluorooctyl
acrylate ("FOA"), 1,1-dihydroheptafluorobutoxy methyl
oxetane (p(FOX7)), and 1,1-Dihydroperfluorooctyl acrylate
' 2 1 97303
-11-
("FOMA"); fluoroolefin monomers such as
tetrafluoroethylene, fluorostyrene monomers such as a-
fluorostyrene, ,B-fluorostyrene, cY, ,B-difluorostyrene 9,
~"B-difluorostyrenes, ~x"B,,B-trifluorostyrenes, a-
5 trifluoromethylstyrenes, 2, 4, 6 -Tris ( -
trifluoromethyl)styrene, 2,3,4,5,6-pentafluorostyrene,
2,3,4,5,6-pentafluoro-~-methylstyrene, and 2,3,4,5,6-
pentafluoro-~-methylstyrene; fluoroalkylene oxide
monomers such as perfluoropropylene oxide and
10 perfluorocyclohexene oxide; fluorinated vinyl alkyl ether
monomers; and the copolymers thereof with suitable
comonomers, wherein the comonomers are fluorinated or
unfluorinated. Exemplary siloxane-containing compounds
include alkyl, fluoroalkyl, and chloroalkyl siloxanes.
More preferably, the surfactant comprises a
"CO2-phobic" group along with a CO2-soluble group, such
as a fluoropolymer. The CO2-phobic group may be a
hydrophobic group, such as a polystyrene group, or a
hydrophillic group such as carboxylic acid. Such
20 copolymers can take many forms; exemplary forms are graft
copolymers, random copolymers, and block copolymers.
Other suitable surfactants that are surface
active in carbon dioxide include
CF3--(CF2)~--(CF2h--CF3
CF3--(CF2)~--(CF2h--OH
CF3--(CF2~--CH=CH--(CF~b,--CF3
OH
CF3--(CF2~--CH2--CH--CH2OH
CF3 1~
CF3--(CF2)~--O--CF--C~--Cl~
CF3--(CF2)~--C--OH
- 21 97303
lc~
CF3--(CF2~--R--(C~C~h -C~C~CH3
[~
where x=1-30 and y=1 to 30. The x and y values are
chosen to adjust the balance between "CO2-philic~ and
"CO2-phobic" to tailor the surface activity of the
reagents.
Exemplary silicone-containing surfactants
(i.e., siloxane polymers cr copolymers) include
CH3 lcii
i3u--(CH2 -CH~--(Si-Oh -Sl-Ci~i3
CH3 Ci-i3
CH3 CH3 IcH3
CH3--(Cl~ (Si-O~-Si CH--CH2ci'i3
CH3 CHs
wherein x and y are varied to adjust to "CO2-philic" and
"CO2-phobic" balance.
The polymerizing step of the present invention
can be carried out by polymerization methods using
apparatus and conditions known to those skilled in this
art. For example, the polymerization reaction is carried
out in a suitable high pressure reaction vessel of about
24 mL and capable of withstanding pressures on the order
of up to about 8000 psi. The reaction vessel typically
includes a cooling system. Additional features of the
reaction vessel used in accordance with the invention
include heating means such as an electric heating furnace
to heat the reaction mixture and mixing means, i.e.,
stirrers such as paddle stirrers, impeller stirrers, or
multistage impulse countercurrent agitators, blades, and
21 97303
.
'
the like. Typically, the reaction begins by cooling the
reaction vessel to a temperature below about 31~C. The
initiator, monomer or monomers, and carbon dioxide are
added to the vessel. Typically the mixture is allowed to
polymerize for between about 2 and 24 hours, and
preferably is stirred as the reaction proceeds. At the
conclusion of the reaction, the polymer can be collected
by methods such as venting of the carbon dioxide or by
fractionation. After separation, the polymer can be
collected by conventional means. In addition, the
polymers of the present invention may be retained in the
carbon dioxide, and sprayed onto a surface. After the
carbon dioxide and solvent evaporate, the polymer forms
a coating on the surface.
The polymer formed by the present invention can
also be used to form molded articles, such as valves and
bottles, films, fibers, resins, and matrices for
composite materials.
The present invention is explained in greater
detail in the following examples. As used herein, "M"
means molar concentration, "NMR" means nuclear magnetic
resonance, "MHz" means megahertz, "GPC" means gas phase
chromatography, ~A~ means angstroms, " W " means
ultraviolet, "g" means grams, "mol" means moles, "mL"
means milliliters, "C" means degrees Centigrade, "S"
means seconds, "h" means hours, "psig" means pounds per
square inch (gauge), IIMnl' means number average molecular
weight, "MWD" means molecular weight distribution, "f"
means functionality, "ppm" means parts per million, IITgl'
means glass transition temperature, "nm~' means
nanometers, "mg" means milligrams, "rpm~' means
revolutions per minute, "mm Hg" means millimeters of
mercury, and "psi" means pounds per square inch. These
Examples are illustrative and are not to be taken as
limiting of the invention.
21 97303
,
-
EXAMPLE 1
ExDerilllentdl Procedures and Materials
Monomers of isobutyl vinyl ether, styrene, and
3, 3 ~ -bisethoxymethyl oxetane were provided by Dr. Gerald
Manser of Aerojet Corporation. Bisethoxymethyl oxetane
(BEMO) was vacuum distilled at 5 X 10-2 mm Hg, with the
fraction distilling at 54~C to 57~C being collected.
Styrene was vacuum distilled from calcium hydride at 5 x
10-2 mm Hg and 50~C. Isobutyl vinyl ether was distilled
twice from calcium hydride under an argon atmosphere at
about atmospheric pressure and a temperature of 82 ~C .
Lewis acid catalysts ethyl aluminum dichloride ( 1. 0 M in
hexanes, obtained from Aldrich) and tin tetrachloride
(obtained from Aldrich) were used without further
purification. Lewis acid catalyst boron trifluoride
tetrahydrofuranoate (BF3-THF) was prepared by stirring
boron trifluoride diethyletherate (obtained from Aldrich)
with prechilled tetrahydrofuran (obtained from
Mallinckrodt) for two hours at 25~C. BFCl-THF was
purified by distillation at 100~ under argon to remove
volatiles, followed by vacuum distillation with the
fraction distilling at 70~C being isolated. The acetic
acid/isobutyl vinyl ether adduct was prepared as
described by T. Hagashimura et al. Macromolecules 22 (3):
1009 (1989). Isobutyl vinyl ether (IBVE) was treated
with acetic acid for three hours at 60~C and atmospheric
pressure, then the adduct was distilled twice under
vacuum at 5 X 10-2 mm Hg with the middle fraction, which
is distilled over at about 60~C, being collected both
3 0 times to prepare the ester initiator .
Initiators 1, 4-butanediol, 2, 2, 2-
trifluoroethanol, and 1-phenyl-1-chloroethane (obtained
from Aldrich) were used without further purification.
The deactivator, ethyl acetate was obtained from Aldrich
and was distilled twice from calcium hydride under an
argon atmosphere. Cyclohexane was obtained from Phillips
Petroleum and was stirred over concentrated sulfuric acid
2 1 q7303
-15-
for two weeks, decanted, and distilled from sodium metal
under an argon atmosphere. Methylene chloride was
obtained from Mallinckrodt, and, was distilled twice from
calcium hydride under an argon atmosphere. Carbon
dioxide was obtained from Matheson, 99.99~ was passed
through copper oxide catalyst column to remove trace
amounts of oxygen and then through a 3A molecular sieve
column to remove trace amounts of moisture. The high
pressure reactor was constructed from Hastelloy C-22,
having a volume of 24 mL and a pressure capacity of up to
about 8000 psi and was obtained from Haynes
International.
- EXAMPLE 2
PolY",e,iLdlion in CYclohexane in the Absence of Ester Initiator
Before running polymerization in supercritical
carbon dioxide, a series of polymerization were conducted
in cyclohexane. The monomer employed was isobutyl vinyl
ether.
A 300 mL round-bottom glass flask equipped with
a teflon stirring bar and sealed with a rubber septa, is
flame dried under an argon atmosphere. IBVE (10 mL, 7.68
g), ethyl acetate (10 mL), and cyclohexane (30 mL) were
combined in the flask. The temperature of the flask is
maintained near 40~C using a water bath, and stirring is
achieved using a stir plate. Ethyl aluminum dichloride
(EtAlCl2) (0.38 mL, 0.38 mmol) is added via syringe to
catalyze the polymerization, with trace amounts of water
being added as the initiator. The reaction proceeds for
twelve hours at which time a solution of sodium ethoxide
in ethanol is added to the flask to terminate the
reaction. The resulting polymer is precipitated into
methanol, filtered, and dried in vacuum overnight. The
polymerization conditions, yields and molecular weight
data are summarized in Table 1.
-' 21 97303
TABLE 1
Sample feed ratio Mw Mn MWD Yield
monomer ethyl acetate EtAlCl, solvent (x 103) (x 10 3)
(9l (mL) (mmol)~ (mL)
mrcA137 3.072 4 0.31 12 165 107 l.S --
mrcB137 7.68 10 0.38 30 134 80 1.7 --
both polymerizations are run at 40~C
EXAMPLE 3
Pohl",e,i~d~iGn of IsobutYI vinYI ether (IBVE) in S~l er~ ical
Carbon Dioxide in the Absence of Ester Initiator
Ethyl acetate (3 mL) and EtAlCl2 (0.46 mL, 0.46
mmol) are added to the high pressure cell via syringe
under an argon atmosphere. The cell is equipped with a
teflon coated stir bar and heated to 40~C. Carbon
dioxide is added to the cell using a high pressure
syringe to achieve a cell pressure of 4500 psi. IBVE (3
mL, 2.304 g) is added to the cell using a high pressure
syringe. The reaction continued for fourteen (14) hours
and was accompanied by a pressure drop, to a final
pressure of 3683 psi. During the course of the reaction,
polymer could be seen forming and precipitating from the
carbon dioxide fluid.
At the end of the polymerization, carbon
dioxide -is vented slowly to leave the polymer in the
cell. The reaction is terminated using a solution of
sodium ethoxide in ethanol. The polymer is then
dissolved in cyclohexane or a solution of
cyclohexane/tetrahydrofuran, precipitated into a large
excess of methanol, filtered and dried in vacuum
overnight. Poly(isobutyl vinyl ether) (1.997 g) was
recovered. (Yield = 87%).
Characterizations: 1H NMR spectra show the
expected patterns, without vinyl proton peaks of the
monomer and without any indication of incorporation of
carbon dioxide into the polymer backbone. The FTIR
- 21 97303
-17-
spectrum are consistent with the corresponding
homopolymer made in cyclohexane, with no carbonyl peak
present. Gel permeation chromatography (GPC) analysis
show Mn = 1.51 x 105, Mw = 5.99 x 105, and MWD = 4.o.
EXAMPLE 4
Pol~",e,i~dtion of IsobutYI vinYI ether (IBVE) in Su~ercritical
Carbon Dioxide in the Absence of Ester Initiator
Ethyl acetate (4 mL) and ethyl aluminum
dichloride (0.25 mL, 0.25 mmol) are added to the high
pressure cell. Following the same procedure in Example
3, carbon dioxide and isobutyl vinyl ether (4 mL,
3.702 g) are added for a final pressure of 4200 psi. The
reaction proceeds for twenty-two hours at 40~C, during
which time pressure within the cell decreases to 3860
psi. Poly(IBVE) (2.211 g) is recovered. (Yield = 72~).
Characterization: 1H NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates MN = 8.0 x 104, Mw = 5.2 x
105, and MWD = 6.5.
EXAMPLE ~
PolY",eli~dlion of IsobutYI viml ether (IBVE) in SuDe~ ical
Carbon Dioxide in the Absence of Ester Initiator
Ethyl acetate (4 mL) and ethyl aluminum
dichloride (0.5 mL, 0.5 mmol) are added to the high
pressure cell. Following the same procedure as described
in Example 3, carbon dioxide and IBVE (4 mL, 3.072 g) are
added for a final pressure of 4200 psi. The reaction
proceeds for 23 hours at 40~C. Poly(IBVE) (1.277 g) is
recovered. (Yield = 44~).
Characterizations: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates Mn = 5.2 x 104, Mw = 2.8 x
105, and MWD = 5.4.
- 2~ 9~303
EXAMPLE 6
ComParative Exam~le: PolYmerization in CYclohexane
in the Presence of Ester Inidator
A 300 mL round-bottom glass flask equipped with
a teflon stirring bar and sealed with a rubber septa, is
flame dried under an argon atmosphere. IBVE (10 mL, 7.68
g), ethyl acetate (9.8 mL), the ester initiator (0.06 mL,
0.31 mmol), and cyclohexane (100 mL~ are combined in the
flask. The temperature of the flask is maintained near
40~C using a water bath and stirring is achieved with a
stir plate. Ethyl aluminum dichloride (EtAlCl2) (0.40 mL,
~ 0.40 mmol) is added via syringe to catalyze the
polymerization. The reaction proceeds for twenty-four
hours at which time a solution of sodium ethoxide in
ethanol is added to the flask to terminate the reaction.
The resulting polymer is precipitated into methanol,
filtered, and dried in vacuum overnight. Poly(IBVE)
(3.35 g) is recovered. (Yield = 44%).
Characterization: GPC indicates Mn = 7.0 x 103,
Mw = 8.1 x 103, MWD = 1.15.
EXAMPLE 7
PolY,ne,i~dLion of IsobutYI viml ether (IBVE) in SuDercritical
Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (2.4 mL), EtAlCl2 (0.2 mL, 0.2
mmol), and the ester initiator (0.04 mL, 0.23 mmol) are
combined in the cell. Following the procedure as
described in Exa~ple 3, carbon dioxide and IBVE ( 3 ml,
2.304) are added to achieve a pressure of 4800 psi. The
reaction proceeds for thirteen hours at 40~C, during
which time the pressure within the cell drops to 3800
psi. Poly(IBVE) (2.11 g) is recovered. (Yield = 91%).
Characterization: 1H NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates Mn = 6.7 x 103, Mw = 1.2 x
1o4, and MWD = 1.8.
2 1 97303
.~
-19-
EXAMPLE 8
Pol~1llleliLd~ion of IsobutYI vinYI ether (IBVÉ) in Su~ele,
Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (2.4 mL), EtAlCl2 (0.2 ml, 0.2
mmol), and the ester initiator (0.01 mL, 0.06 mmol) are
combined in the cell. Following the same procedure as
described in Example 3, carbon dioxide and IBVE (3 ml,
2.304) are added to achieve a pressure of 5000 psi. The
reaction proceeds for twelve hours, during which time the
pressure drops to 4041 psi.
Characterization: 1H NMR and FTIR spectra are
~ consistent with those of the homopolymer made in
cyclohexane.
EXAMPLE 9
15POIYIIIel iLd~iOI) of IsobutYI viml ether (IBVE) in Liauid
Grbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (2.4 mL), EtAlCl2 (0.2 mL, 0.2
mmol), and the ester initiator (0.04 mL, 0.23 mmol) are
combined in the cell. Following the same procedure
described in Example 3, carbon dioxide and IBVE (3 mL,
2.304 g) are added to a pressure of 5200 psi. The
reaction proceeds for twelve hours at 30~C, during which
time the pressure drops to 3236 psi.
Characterization: 1H NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC lndicates Mn = 1.4 x 104, Mw = 2.0 x
104, MWD = 1.4.
EXAMPLE 10
PolY",e,iLd~ion of IsobutYI viml ether (IBVE) in SuPer~ icdl
30Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (2.4 mL), EtAlC12 (0.2 mL, 0.2
mmol), and the ester initiator (0.04 mL, 0.23 mmol) are
combined in the cell. Following the same procedure
- 219~3~3
-20-
described in Ex~ple 3, carbon dioxide and IBVE (3 mL,
2.304 g) are added to a pressure of 5000 psi. The
reaction proceeds for twelve hours at 60~C, during which
time the pressure drops to 4200 psi. Poly(IBVE) (2.043
g) is recovered. (Yield = 92~).
- Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates Mn = 1.4 x 104, Mw .= 2.0 x
104, MWD = 1 .4 .
o EXAMPLE 11
Pol~.l.e-i~dLion of IsobutYI viml ether (IBVE) in Su~ercritical
Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (1.2 mL), EtAlC12 (0.2 mL, 0.2
mmol), and the ester initiator (0.04 mL, 0.23 mmol) are
combined in the cell. Following the same procedure
described in Example 3, carbon dioxide and IBVE (3 mL,
2.304 g) are added. The reaction proceeds for twelve
hours at 40~C. Poly(IBVE) (1.994 g) is recovered.
(Yield = 87~).
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates Mn = 2.3 x 104, Mw = 8.7 x
104, MWD = 3.9.
EXAMPLE 1 2
25 PolY.. ,e,i~d~ion of IsobutYI vinyl ether (IBVE) in Su~,e,~ ical
Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (4.8 mL), EtAlC12 (0.2 mL, 0.2
mmol), and the ester initiator (0.04 mL, 0.23 mmol) are
combined in the cell. Following the same procedure
described in Example 3, carbon dioxide and IBVE (3 mL,
2.304 g) are added to the cell to a pressure of 5000 psi.
The reaction proceeds for twelve hours at 40~C, during
which time the pressure drops to 4050 psi. Poly(IBVE)
(1.063 g) is recovered. (Yield = 46~).
-' 2 1 97303
-
-21-
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC lndicates Mn = 3.4 x 10~, Mw = 4.8 x
103, MWD = 1.4.
EXAMPLE 1 3
PolY",~ d~ion of IsobutYI viml ether (IBVE) in SuDel.,iLical
Carbon Dioxide in the Presence of Ester Initiator
EtAlCl2 (0.2 mL, 0.2 mmol), and the ester
initiator (0.04 mL, 0.23 mmol) are combined in the cell.
Following the same procedure described in Example 3,
~ carbon dioxide and IBVE (3 mL, 2.304 g) are added to the
cell to a pressure of 5000 psi. The reaction proceeds
for twelve hours at 40~C, during which time the pressure
drops to 3300 psi. Poly(IBVE) (1.614 g) is recovered.
(Yield = 70%).
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates Mn = 1.3 x 104, Mw = 3.9 x
104 MWD = 2.9.
EXAMPLE 14
PolY",~,iLdliGn of IsobutYI vinYI ether (IBVE) in Su~e~ ical
Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (2.4 mL), EtAlCl2 (0.2 mL, 0.2
mmol), and the ester initiator (0.02 mL, 0.12 mmol) are
combined in the cell. Following the same procedure
described in Example 3, carbon dioxide and IBVE (3 mL,
2.304 g) are added to the cell to a pressure of 4500 psi.
The reaction proceeds for twelve hours at 40~C.
Poly(IBVE) (2.245 g) is recovered. (Yield = 93~).
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates Mn = 1.4 x 104, Mw = 2.0 x
104, MWD = 1.4.
- 21 97303
EXAMPLE t 5
Pol~,l,leli~dLion of Isobutyl vinYI ether (IBVE) in SuPercritical
Carbon Dioxide in the Presence of Ester Initiator
Ethyl acetate (2.0 mL), EtAlCl2 (0.2 mL, 0.2
mmol), and the ester initiator (0.02 mL, 0.12 mmol) are
combined in the cell. Following the same procedure
described in Example 3, carbon dioxide and IBVE (3 mL,
2. 304 g) are added to the cell to a pressure of 4955 psi.
The reaction proceeds for twelve hours at 60OC, during
which time the pressure had dropped to 3957 psi.
Characterization: lH NMR and FTI~ spectra are
consistent with those of the homopolymer made in
cyclohexane. GPC indicates a bimodal molecular weight
distribution.
EXAMPLE 16
ComDarative ExamDle: PolYIlleli~ n of 3.3'-
bisethoxymethYI oxetane in MethYlene Chloride
Polymers of 3,3'-(bisethoxymethyl)oxetane
(BEMO) are prepared in methylene chloride. A 300 mL
round-bottom glass flask equipped with a teflon stirring
bar and sealed with a rubber septa, was flame dried under
an argon atmosphere. BEMO (4 mL, 3.99 g), and methylene
chloride (20 mL) are combined in the flask. If no
external proton source (i.e., initiator) is added,
adventitious water was employed as the proton source.
The temperature of the flask is maintained near 10~C
using an ice bath and stirring is achieved with a stir
plate. The catalyst boron trifluoride
tetrahydrofuranoate (BF3-THF) (0.06 mL, 0.58 mmol) is
added via syringe to catalyze the polymerization, with
trace amounts of water being added as the initiator. The
reaction proceeds for four hours at which time a solution
of aqueous sodium hydroxide is added to the flask to
terminate the reaction. The resulting polymer is
precipitated into methanol, filtered, and dried in vacuum
21 97303
-23-
overnight. Table 2 summarizes the results obtained in
methylene chloride.
Table 2
S~mple feed r~tio Mw Mn MWD ~ield
monomer proton source BF3-THF solvent (x 103) (x io-3)
(g) (mmol) (mL)
mcllO9~B 3.99 -- O.58 20 19.9 35.9 1.8 61~
mclll94 3.99 -- 0.58 20 17.6 34.9 1.9 70S
mcBF3A 3.99 -- 0.58 20 29.3 63.7 2.2 77~
mcBOOA 3.99 BOO 1.16 20 17.9 30.5 1.7 37S
mcS494 3.99 CF3CH20H 0.58 20 33.2 72.4 2.2 79
1 O mcSl094 3.99 CF3CH20H 2.32 20 28.0 55.6 1.7 64
mc51894 3.99 CF3CH20H 2.32 20 28.1 57.1 2.0 76
EXAMPLE 1 7
PolY",e,i~dlion of 3,3'-(bisethoxYmethYI)oxetdne (BEMO)
in Liauid Cdrbon Dioxide
I5 The high pressure cell is equipped with a
Hastelloy C-22 dish to allow both monomer and catalysts
to be added to the cell before the carbon dioxide and not
premix. BEMO (4.8 mL, 4.8 g) is added to the body of the
high pressure cell via syringe under an argon atmosphere.
BF3-THF (0.28 mL, 0.69 mmol) is added to the Hastelloy
dish via syringe under an argon atmosphere. The cell is
equipped with a stir bar and the temperature is
maintained near -lO~C using a sodium chloride/ice bath.
Carbon dioxide is added to the cell using an ISCO~ high
pressure syringe pump to a pressure of 4300 psi. The
reaction proceeds for four hours, during which time the
pressure drops to 3500 psi. Carbon dioxide is slowly
vented and the reaction is terminated using an aqueous
; solution of sodium hydroxide. The polymer is dissolved
in tetrahydrofuran and precipitated -in methanol,
filtered, washed with dilute hydrochloric acid and water,
.' 2197303
-
-24-
then dried overnight in a vacuum. Poly(BEMO) (3.210 g)
is recovered. (Yield = 67~)
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer prepared in
methylene chloride. GPC indicates Mn = 8.1 x 103, Mw =
2.2 x 104, MWD = 2.7.
EXAMPLE 1 8
PolYIlleli~d~Gn of 3.3'-(bisethoxYmethYI)oxetdne (BEMO)
in Liauid Grbon Dioxide
Reaction is conducted as described in Example
~ 17. Carbon dioxide is added to a pressure of 4800 psi.
Poly(BEMO) (1.484 g) is recovered. (Yield = 31~).
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
methylene chloride. GPC indicates Mn = 9.0 x 103, Mw =
2.8 x 104, MWD = 3.1.
EXAMPLE 1 9
PolYmeliLdliGIl of 3,3'-(bisethoxYmethYI)oxetdne (BEMO)
in Liauid Cdrbon Dioxide
BEMO (4.8 mL, 4.8 g) and 1,4-butanediol (0.06
mL, 0.69 mmol) are added to the cell. Following the same
procedure described in Example 17, BF3-THF (0.15 mL, 1.38
mmol) is added to the cell. Carbon dioxide is added to
an initial pressure of 4800 psi. Poly(BEMO) (2.08 g) is
recovered. (Yield = 43~).
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
methylene chloride. GPC indicates Mn = 7.3 x 103, Mw =
1.2 x 104, MWD = 1.6.
21 97303
'
-25-
EXAMPLE 20
Pol~ime,i~dtion of 3.3'-(bisethoxYmethYl)oxetane (BEMO)
in Liquid Carbon Dioxide
Reaction is conducted as described in Ex~mple
18, except the initial pressure of carbon dioxide is 3000
psi. Poly(BEMO) (0.74 g) is recovered. (Yield = 16~).
Characterization: lH NMR and FTIR spectra are
- consistent with those of the homopolymer made in
methylene chloride. GPC indicates Mn = 1.0 x 104, Mw =
1.6 x 104, MWD = 1.6.
- EXAMPLE 21
PolYIneli~d~ion of 3,3'-(bisethox~nnethYl)oxetane (BEMO)
in Liauid Carbon Dioxide
Reaction is conducted as described in Example
19, except that 1,4-butanediol is premixed with BF3-THF
and then injected into the reactor dish. BEMO (4.8 mL,
4.8 g) is added to the body of the cell. BDo/BF3-THF
solution (0.22 mL, 0.69 mmol) is injected into the dish
within the cell. Carbon dioxide is added to a pressure
of 4200 psi. Poly(BEMO) (0.840 g) is recovered.
(Yield = 18%).
Characterization: lH NMR and FTIR spectra are
consistent with those of the homopolymer made in
methylene chloride. GPC indicates Mn = 1.2 x 104, Mw =
2.0 x 104, MWD = 1.7.
EXAMPLE 22
ComDarative Exam~le: PolYIlle.iLdLiGn of StYrene
in MethYlene Chloride
Polymers of styrene are prepared in methylene
chloride using a method outlined by T. Higashimura et
al., Macromolecules 26:744 (1993).
A 300 mL round-bottom glass flask equipped with
a teflon stirring bar and sealed with a rubber septa, is
flame dried under an argon atmosphere. Styrene (4.0 mL,
21 97303
-
-26-
3.64 g), the initiator, l-chloro-1-phenyl ethane (0.5-mL,
0.70 mmol), the deactivator, tetrabutyl ammonium chloride
(2.4 mL, 1.40 mmol), and methylene chloride (20 mL) are
added to the flask via syringe. The temperature of the
flask is maintained near -10~C using an ice bath and
stirring is achieved with a stir plate. The catalyst,
tin tetrachloride (0.7 mL, 3.49 mmol) is added to the
cell via syringe. The reaction proceeds for 3 hours at
-10~C, at which time the reaction is terminated by the
addition of a solution of sodium methoxide and methanol.
The polymer is precipitated into methanol, filtered, and
dried overnight under vacuum. Poly(styrene) (2.813 g) is
recovered. (Yield = 77~).
Characterization: GPC indicates Mn = 4.2 x 103,
Mw = 4.9 x 103, MWD = 1.17.
EXAMPLE 23
PolYIlle~ iGn of St~rene in Liquid Carbon Dioxide
The high pressure cell is equipped with a
Hastelloy C-22 dish to allow both monomer and catalysts
to be added to the cell before the carbon dioxide without
pre~'xlng. Styrene (5.0 mL, 4.55 g), 1-chloro-1-phenyl
ethane (0.1 mL, 0.87 mmol), and tetrabutylammonium
chloride (1.9 mL, 1.7 mmol) are added to the body of the
high pressure cell via syringe under an argon atmosphere.
Tin tetrachloride (0.9 mL, 4.41 mmol) is added to the
Hastelloy dish via syringe under an argon atmosphere.
The cell is equipped wlth a stir bar and temperature is
maintained near 0~C using a NESL~3~ circulating bath
equipped with a refrigeration unit and a solution of
water and ethylene glycol as the coolant. Carbon dioxide
is added to the cell using an ISC0~ high pressure syringe
pump to a pressure of 4500 psi. Within minutes, polymer
can be seen forming and precipitating out of solution in
the reactor. The polymerization proceeds for 3 hours
near 0~C, during which time the pressure drops to
approximately 4000 psi. The carbon dioxide is then
2 1 973~3
-27-
slowly vented off and the reaction is terminated by the
addition of a solution of sodium methoxide and methanol.
The polymer is dissolved in tetrahydrofuran, precipitated
into methanol, filtered, and dried under vacuum
overnight. Poly(styrene) (2.3838 g) is recovered.
(Yield = 52~).
Characterization: lH NMR and FTIR spectra are
consistent with that of the homopolymer prepared in
methylene chloride. GPC indicates Mn = 4.4 x 103, Mw =
0 1 .1 X 103, MWD = 2.58.
EXAMPLE 24
PolYIlleli~dliGn of StYrene in Liauid Carbon Dioxide
The reaction is conducted following the same
procedure described in Example 23, with the following
changes. No tetrabutylammonium chloride is added. The
1-chloro-1-phenyl ethane is added to the Hastelloy C-22
dish instead of the body of the cell to allow it to
premix with the tin tetrachloride. Poly(styrene) (1.9903
g) is recovered. (Yield = 44~).
Characterization: 1H NMR and FTIR spectra are
consistent with that of the homopolymer prepared in
methylene chloride. GPC indicates Mn = 2.8 x 103, Mw =
5.3 x 103, MWD = 1.9.
EXAMPLE 25
Catatonic PolYn~el i~dLiGn of IsobutYlene
in Liauid Carbon Dioxide
Isobutylene is polymerized with an initiator
system including 2-chloro-2,4,4-trimethylpentane
(TMPCl)/titanium tetrachloride (TiC14)/Lewis bases, where
the Lewis base include dimethyl sulfoxide, acetamide, or
ethyl acetate, in liquid and supercritical carbon dioxide
using the procedure of Example 23 above. This monomer
has previously been polymerized in liquid solvents, such
21 97303
-
-28-
as methyl chloride. See, M. Sawamoto, Prog. Polym, Sci.
16:111 (1991).
EXAMPLE 26
Cationic Co~olY,l,eri~d~ion of StYrene and IsobutYlene
s in Carbon Dioxide
Styrene is copolymerized with isobutylene using
2-methoxy-2-propyl benzene and titanium tetrachloride in
~ the presence of di-t-butyl pyridine using the method
- described in Example 23 above with one change. The
second monomer (styrene) is added to the cell using a
~ hign pressure syringe once the isobutylene has been
consumed in the reaction. It is known that these two
monomers can form copolymers cationically in the mixed
solvent system methyl chloride/methyl cyclohexane. See,
J. Kennedy, et al. Makromol. Chem., Macromol. Symp.
51:1269 (1991).
EXAMPLE 27
Block CoPolY,ne,iLd~iGn of IsobutYlene
and MethYI VinYI Ether
Isobutylene is cationically block copolymerized
with methyl vinyl ether using the TMPC1/TiC14 initiating
system described in Example 25 in the presence of
tetrabutylammonium chloride in liquid and supercritical
carbon dioxide using the procedure described in Example
26, where methyl vinyl ether is the second monomer. It
is known that these monomers can form block copolymers
cationically in mixed solvent systems such as methyl
chloride/n-hexane or methylene chloride/n-hexane. See,
J. Kennedy, et al., Macromolecules 25:1642 (1992).
EXAMPLE 28
Cationic Cowl~l",eriL~tion of IsobutYlene and Iso~rene
Isobutylene is cationically block copolymerized
with isoprene using cumyl acetate or boron trichloride in
' 2~ 97303
-29-
liquid and supercritical carbon dioxide using the
procedure described in Example 26. Isoprene is the
- second monomer. It is known that these monomers can form
block copolymers cationically in methyl chloride. See,
J. Kennedy, et al. Macromolecules 25:1771 (1992).
EXAMPLE 29
Cationic PolY",eli~dLion of CYCIjC Carbonates
Cyclic carbonates are polymerized cationically
using methyl triflate, methyl iodide, or benzyl bromide
in liquid or supercritical carbon dioxide according to
the method described in Example 17 above.
EXAMPLE 30
Cationic PolY.IleliLdlion of Oxetanes in Carbon Dioxide
Oxetanes are polymerized cationically using
strong acids or Lewis acids and preinitiators such as
alcohols, ethers, and esters in liquid and supercritical
carbon dioxide as described in Exampl- 17 above.
EXAMPLE 3 1
Cadonic CoDolY,.,eli~d~ion of Oxetanes
' and CYCIjC Carbonates
Oxetanes, are copolymerized cationically with
cyclic carbonates using methyl triflate or boron
trifluoride diethyl etherate in liquid and supercritical
carbon dioxide as described in Example 17 above, with one
exception. The oxetane and the cyclic carbonate are
added simultaneously to the cell. The initial cell
temperature is held at 0~C until the oxetane monomer is
consumed. The temperature is then raised to 30~C while
the cyclic carbonate monomer is consumed. It has been
previously known that these monomers could be
copolymerized in methylene chloride and deuterated
chloroform. See, T. Endo, et al ., Macromolecules 26 :7106
(1993).
21 97303
-30 -
EXAMPLE 32
Cationic CoPolY,neriLdlion of Other CYCIjC Monomers
Cyclic monomers, such as oxiranes,
tetrahydrofuran, trioxane, and oxazolines are polymerized
cationically using: (1) triflic acid or (2) Lewis acids
and some proton source such as water or alcohols, in
liquid and supercritical carbon dioxide as described in
Example 17 above. It has been known that these monomers
could be cationically polymerized in solvents such as
nitromethane, methylene chloride, and carbon
tetrachloride. See, E. Goethals, Makromol. Chem.,
- Macromol . Symp. 42/43:51 (1991).
EXAMPLE 33
PolY"~e,iLdtion of FormaldehYde in Carbon Dioxide
Formaldehyde is polymerized cationically using
hydrochloric acid or Lewis acids such as boron
trifluoride and water in liquid and supercritical carbon
dioxide as described in Example 17 above.
EXAMPLE 34
pol~llleli~d~ion of 3,3'-bisethoxymethYI oxetane (BEMO) in
Liauid Carbon Dioxide in the Presence of Surfactant
The high pressure cell is equipped with a
hastelloy C-22 dish to allow both monomer and catalyst to
be added to the cell before the carbon dioxide while
avoiding premix. Poly(l,l dihydroheptafluorobutoxy
methyl oxetane) (p(FOX7)) (0.9902 g) is added to the
cell. BEMO (4.8 mL, 4.8 g) is added to the body of the
cell via syringe under an argon atmosphere. Boron
trifluoride tetrahydrofuranate (BF3-THF) (0.28 mL, 0.69
mmol) is added to the hastelloy dish via syringe under an
argon atmosphere. The cell is equipped with a mechanical
stirrer to allow the contents to be agitated during the
reaction and temperature is maintained near 5OC using a
circulating cold bath and a cooling coil around the cell.
21973J3
-
-31-
Carbon dioxide is added to the cell using an ISCO high
pressure syringe pump, to achieve a pressure of 4267 psi.
The reaction proceeds for six hours during which time the
solution changes from clear to an opaque, "milky"
dispersion. The reaction is terminated by venting the
dispersion into deoxygenated, deionized water and
injecting 2 mL of water into the cell. The polymer is
collected and dried overnight under vacuum. Poly(BEMO)
(3.1731 g) is recovered. (Yleld = 66%).
Characterization: GPC indicates Mn = 1.7 x 103
g/mol, Mw = 5.4 x 103 g/mol, and MWD = 3.1.
EXAMPLE 35
PolY"~ a~ion of 3.3'-bisethoxYmethYI oxeLdne (BEMO) in Liquid
Dioxide in the Presence of Surfactdnt
Reaction is set up as described in Example 34,
except poly(1,1-dihydroperfluorooctyl acrylate) (p(FOA))
is used as the surfactant instead of poly(FOX7). Carbon
dioxide is added to a pressure of 4200 psi. Stirring is
halted after 4 hours, 25 minutes has elapsed. The
"milky" dispersion described in Example 34 did not
precipitate after termination of stirring. Reaction is
terminated after a total reaction time of 4 hours, 35
minutes by venting into deoxygenated methanol and
addition of 4 mL of deoxygenated methanol to the
depressurized cell. Poly(BEMO) (3.043 g) is recovered.
(Yield = 63%).
Characterization: GPC indicates Mn = 1.4 x 104
g/mol, Mw = 4.6 x 104 g/mol, and MWD = 3.3
EXAMPLE 36
polylll~ d~ion of IsobutYlene in Liauid Cdrbon Dioxide in the
Presence of Su, rdc~dnt
p(FOA) (0.8403 g) is added to the high pressure
reactor. Tin tetrachloride (0.05 mL, .43 mmoles) is
added to the cell via syringe under an argon atmosphere.
2 1 97303
Carbon dioxide is added as described in Example 34 to a
pressure of 1285 psi. Cell temperature was 1.2~C.
Isobutylene (3.4 g, 0.06 moles) is added slowly using a
high pressure syringe pump to a final cell pressure of
4150 psi. The reaction began clear, but became
increasingly cloudy as the reaction proceeds. Reaction
proceeded for twenty-two hours at which time it is
terminatedby depressurization of the cell contents into
deoxygenated methanol and injection of 3 mL of
deoxygenated methanol into the cell. The product polymer
with surfactant can be redispersed in Freon-113 as a
stable suspension. Poly(isobutylene) (0.57 g) is
recovered, (17~ yield).
Characterization: GPC indicated a product of
bimodal molecular weight, with peak molecular weights of
1.8 x 103 g/mol and 3.9 x 103 g/mol.
The foregoing is illustrative of the present
invention and is not to be construed as limiting thereof.
The invention is defined by the following claims, with
equivalents of the claims to be included therein.
