U.S. patent application number 10/650256 was filed with the patent office on 2004-04-15 for control agents for living-type free radical polymerization and methods of polymerizing.
This patent application is currently assigned to Symyx Technologies, Inc.. Invention is credited to Chang, Han-Ting, Charmot, Dominique, Nava-Salgado, Victor.
Application Number | 20040073042 10/650256 |
Document ID | / |
Family ID | 28673520 |
Filed Date | 2004-04-15 |
United States Patent
Application |
20040073042 |
Kind Code |
A1 |
Charmot, Dominique ; et
al. |
April 15, 2004 |
Control agents for living-type free radical polymerization and
methods of polymerizing
Abstract
Control agents that have an oxygen-nitrogen bond covalently
bonded to a thiocarbonyl moiety are provided for living-type free
radical polymerization of a wide variety of monomers, particularly
vinyl monomers.
Inventors: |
Charmot, Dominique;
(Campbell, CA) ; Chang, Han-Ting; (Livermore,
CA) ; Nava-Salgado, Victor; (San Jose, CA) |
Correspondence
Address: |
SYMYX TECHNOLOGIES INC
LEGAL DEPARTMENT
3100 CENTRAL EXPRESS
SANTA CLARA
CA
95051
|
Assignee: |
Symyx Technologies, Inc.
|
Family ID: |
28673520 |
Appl. No.: |
10/650256 |
Filed: |
August 27, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10650256 |
Aug 27, 2003 |
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10104740 |
Mar 22, 2002 |
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6667376 |
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Current U.S.
Class: |
546/335 ;
548/571; 558/168; 558/234 |
Current CPC
Class: |
C07D 209/30 20130101;
C07D 295/24 20130101; C07C 329/16 20130101; C07D 291/06 20130101;
C07C 2601/14 20170501; C07D 207/46 20130101; C08F 2/38 20130101;
C08F 293/005 20130101 |
Class at
Publication: |
546/335 ;
548/571; 558/168; 558/234 |
International
Class: |
C07F 009/02; C07C
337/00 |
Claims
What is claimed is:
1. A compound characterized by the general formula: 21wherein
R.sup.1 is any group that can be expelled as its free radical form
in an addition-fragmentation reaction; R.sup.2 and R.sup.3 are each
independently selected from the group consisting of hydrogen,
hydrocarbyl, substituted hydrocarbyl, heteroatom-containing
hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and
combinations thereof, and optionally R.sup.2 and R.sup.3 are joined
together in a ring structure having from 3 to 50 atoms in the
backbone of the ring; also optionally, R.sup.2 and R.sup.3 are
joined together to form a double bond optionally substituted
alkenyl moiety.
2. The compound of claim 1, wherein R.sup.1 is selected from the
group consisting of optionally substituted alkyl, optionally
substituted aryl, optionally substituted alkenyl, optionally
substituted alkoxy, optionally substituted heterocyclyl, optionally
substituted alkylthio, optionally substituted amino and optionally
substituted polymer chains.
3. The compound of claim 2, wherein R.sup.1 is selected from the
group consisting of --CH.sub.2Ph,
--CH(CH.sub.3)CO.sub.2CH.sub.2CH.sub.3,
--CH(CO.sub.2CH.sub.2CH.sub.3).sub.2, --C(CH.sub.3).sub.2CN,
CH(Ph)CN, --C(CH.sub.3).sub.2Ph, --CH(CH.sub.3)CN, and
--CH.sub.2CH.sub.2CH.sub.2CH- .sub.3.
4. The compound of claim 1, wherein R.sup.2 and R.sup.3 are each
independently selected from the group consisting of hydrogen,
optionally substituted alkyl, optionally substituted aryl,
optionally substituted alkenyl, optionally substituted acyl,
optionally substituted, aroyl, optionally substituted alkoxy,
optionally substituted heteroaryl, optionally substituted
heterocyclyl, optionally substituted alkylsulfonyl, optionally
substituted alkylsulfinyl optionally-substituted alkylphosphonyl,
optionally substituted arylsulfinyl, and optionally substituted
arylphosphonyl.
5. The compound of claim 1, wherein R.sup.2 and R.sup.3 form an
optionally substituted heterocycle ring.
6. The compound of claim 1, wherein the compound is selected from
the group consisting of: 22
7. A compound characterized from any of the following general
formulas: 23wherein R.sup.1 is any group that group that can be
expelled as its free radical form in an addition-fragmentation
reaction; R.sup.2 and R.sup.3 are each independently selected from
the group consisting of hydrogen, hydrocarbyl, substituted
hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted
heteroatom-containing hydrocarbyl, and combinations thereof; and
optionally R.sup.2 and R.sup.3 together to form a double bond
optionally substituted alkenyl moiety; and also optionally R.sup.2
and R.sup.3 together joined in a ring structure having from 3 to 50
atoms in the ring backbone; Core is a core molecule; c is 1 or
more; and d is 2 or more.
8. The compound of claim 7, wherein R.sup.1 is selected from the
group consisting of optionally substituted alkyl, optionally
substituted aryl, optionally substituted alkenyl, optionally
substituted alkoxy, optionally substituted heterocyclyl, optionally
substituted alkylthio, optionally substituted amino and optionally
substituted polymer chains.
9. The compound of claim 8, wherein R.sup.1 is selected from the
group consisting of --CH.sub.2Ph,
--CH(CH.sub.3)CO.sub.2CH.sub.2CH.sub.3,
--CH(CO.sub.2CH.sub.2CH.sub.3).sub.2, --C(CH.sub.3).sub.2CN,
--CH(Ph)CN and --C(CH.sub.3).sub.2Ph, --CH(CH.sub.3)CN,
--CH.sub.2CH.sub.2CH.sub.2CH- .sub.3.
10. The compound of claim 7, wherein R.sup.2 and R.sup.3 are each
independently selected from the group consisting of hydrogen,
optionally substituted alkyl, optionally substituted aryl,
optionally substituted alkenyl, optionally substituted acyl,
optionally substituted, aroyl, optionally substituted alkoxy,
optionally substituted heteroaryl, optionally substituted
heterocyclyl, optionally substituted alkylsulfonyl, optionally
substituted alkylsulfinyl, optionally substituted alkylphosphonyl,
optionally substituted arylsulfinyl, and optionally substituted
arylphosphonyl.
11. The compound of claim 7, wherein wherein R.sup.2 and R.sup.3
form an optionally substituted heterocycle ring.
12. The compound of claim 7, wherein Core is selected from the
group consisting of: 24
13. The compound of claim 7, wherein the compound is selected from
the group consisting of: 25
Description
FIELD OF THE INVENTION
[0001] The present invention relates to new compounds useful in
assisting in the polymerization of monomers in a free radical
polymerization that has living-type kinetics. Polymers made with
the control agents and processes for polymerization are also
included.
BACKGROUND OF THE INVENTION
[0002] The use and mechanism of control agents for free radical
polymerization is now generally known; see for example U.S. Pat.
No. 6,153,705, WO 98/01478, WO 99/35177, WO 99/31144, and WO
98/58974, each of which is incorporated herein by reference.
Despite this knowledge, there remains a need for new agents that
may lead to a commercializable process. In particular, control
agents that work to control the polymerization of vinyl monomers
are of interest. In this context, vinyl monomers are typically
monomers with a radically polymerizable double bond not conjugated
to any other double bonds such as C.dbd.C, C.dbd.O or C.ident.N.
Typical examples of vinyl monomers include vinyl acetate,
vinylformamide, vinyl pyrrolidone and olefins (such as
.alpha.-olefins).
[0003] The control agents described in WO 98/01478, WO 99/35177, WO
99/31144, and WO 98/58974 generally operate according to a
reversible addition-fragmentation transfer mechanism, which confers
a "living" character to the free radical polymerization of
ethylenic monomers. These control agents, however have not been
known to show control of the polymerization of vinyl monomers, such
as vinyl acetate. Typically, when using the known control agents
with vinyl monomers, the polymerization reaction is either
unacceptably slow (e.g., an inhibition effect is observed) or
uncontrolled.
[0004] In U.S. Pat. No. 6,153,705, control agents of the xanthate
type (for instance, CH(CH3)(CO.sub.2Et)S--C(.dbd.S)OEt) are
disclosed that may at least partially control the polymerization of
vinyl acetate. However, even partial loss of control is undesirable
for certain applications.
[0005] This invention provides control agents that unexpectedly
provide superior control in the polymerization of vinyl monomers in
comparison to known control agents. In particular these new control
agents give a narrower molecular weight distribution when compared
with known control agents, and, as opposed to the latter, they show
a continuous decrease in the polydispersity as the monomer
conversion increases. These modified properties allow for improved
conditions of the polymerization process and/or improved properties
of the polymers obtained from the processes. These control agents
showed unexpectedly good results in the control polymerization of
vinyl type monomers, such as vinyl acetate, vinylformamide, vinyl
pyrrolidone and ethylene.
SUMMARY OF THE INVENTION
[0006] This invention provides control agents that are have an O--N
bond covalently bonded to a thiocarbonyl moiety. In some
embodiments the control agents can be characterized by the general
formula: 1
[0007] wherein R.sup.1 is generally any group that is sufficiently
labile to be expelled as its free radical form; R.sup.2 and R.sup.3
are each independently selected from the group consisting of
hydrogen, hydrocarbyl, substituted hydrocarbyl,
heteroatom-containing hydrocarbyl, and substituted
heteroatom-containing hydrocarbyl, and combinations thereof, and
optionally, R.sup.3 combines with R.sup.2 to form a ring structure,
with said ring having from 3 to 50 non-hydrogen atoms.
[0008] Another aspect of this invention is directed toward
multi-functional control agents, so that the control agents may
occupy either a central portion of a polymer chain and/or two or
more ends of a polymer. In those embodiments where the control
agent occupies a central portion of the polymer backbone, the
oxygen-nitrogen bond provides the unique opportunity to degrade the
polymer backbone into smaller pieces by external stimuli (e.g.,
heat, chemical reaction, irradiation, etc.). Such a process is
unique as compared to known free radical polymerization and
"living" free radical polymerization techniques. In addition, some
of the multi-functional control agents are cyclic, which provide
the unique opportunity to prepare block copolymers with reduced
processes steps. Furthermore, some multi-functional control agents
allow for ring opening polymerizations, which heretofore have not
found commercial applications in free radical polymerization.
[0009] In another aspect, this invention provides control agents
that are easy to prepare and economically useful on a commercial
scale (e.g., batch, semi-batch or continuous).
[0010] Other aspects of this invention include certain of the
control agents, which are novel compounds. Polymerization processes
using all of the control agents of this invention and polymers that
can be made with the control agents of this invention are
additional aspects of this invention. In particular, the control
agents of this invention provide living-type kinetics and as such
allow for the preparation of desired products, including block
polymers, star architectures, grafts and hyperbranched
polymers.
[0011] Thus, it is an object of this invention to provide novel
control agents for a living-type free radical polymerization
process.
[0012] It is another object of this invention to provide novel
compounds, which are useful as control agents in a free radical
polymerization process.
[0013] It is a further object of this invention to provide a novel
system for free radical polymerization of monomers that employs
living-type kinetics, and in particular for vinyl monomers.
[0014] It is still a further object of this invention to polymerize
a variety of monomers under commercially acceptable conditions with
a family of control agents, and in particular for vinyl
monomers.
[0015] It is yet a further object of this invention to make
controlled architecture polymers with a polymerization process that
employs a control agent.
[0016] It is further another object of this invention to provide
multifunctional control agents that may occupy a central portion of
a polymer chain allowing for the polymer chain to be degraded.
[0017] Further aspects and objects of this invention will be
evident to those of skill in the art upon review of this
specification.
DETAILED DESCRIPTION OF THE INVENTION
[0018] In the most general terms, the control agents of this
invention contain at least one O--N bond covalently bonded to a
thiocarbonyl group. In structural terms, the following moiety must
be present in the control agents of this invention: 2
[0019] In describing and claiming the present invention, the
following terminology will be used in accordance with the
definitions set out below. A named R group will generally have the
structure that is recognized in the art as corresponding to R
groups having that name. For the purposes of illustration,
representative R groups as enumerated above are defined herein.
These definitions are intended to supplement and illustrate, not
preclude, the definitions known to those of skill in the art.
[0020] It is also to be understood that the terminology used herein
is for the purpose of describing particular embodiments only, and
is not intended to be limiting. As used in this specification and
the appended claims, the singular forms "a," "an" and "the" include
plural referents unless the context clearly dictates otherwise. In
describing and claiming the present invention, the following
terminology will be used in accordance with the definitions set out
below.
[0021] The following definitions pertain to chemical structures,
molecular segments and substituents:
[0022] As used herein, the phrase "having the structure" is not
intended to be limiting and is used in the same way that the term
"comprising" is commonly used. The term "independently selected
from the group consisting of" is used herein to indicate that the
recited elements, e.g., R groups or the like, can be identical or
different (e.g., R.sup.2 and R.sup.3 in the structure of formula
(1) may all be substituted alkyl groups, or R.sup.2 may be hydrido
and R.sup.3 may be methyl, etc.).
[0023] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the
description includes instances where said event or circumstance
occurs and instances where it does not. For example, the phrase
"optionally substituted hydrocarbyl" means that a hydrocarbyl
moiety may or may not be substituted and that the description
includes both unsubstituted hydrocarbyl and hydrocarbyl where there
is substitution.
[0024] The term "alkyl" as used herein refers to a branched or
unbranched saturated hydrocarbon group typically although not
necessarily containing 1 to about 24 carbon atoms, such as methyl,
ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl,
decyl, and the like, as well as cycloalkyl groups such as
cyclopentyl, cyclohexyl and the like. Generally, although again not
necessarily, alkyl groups herein contain 1 to about 12 carbon
atoms. The term "lower alkyl" intends an alkyl group of one to six
carbon atoms, preferably one to four carbon atoms. "Substituted
alkyl" refers to alkyl substituted with one or more substituent
groups, and the terms "heteroatom-containing alkyl" and
"heteroalkyl" refer to alkyl in which at least one carbon atom is
replaced with a heteroatom.
[0025] The term "alkenyl" as used herein refers to a branched or
unbranched hydrocarbon group typically although not necessarily
containing 2 to about 24 carbon atoms and at least one double bond,
such as ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl,
octenyl, decenyl, and the like. Generally, although again not
necessarily, alkenyl groups herein contain 2 to about 12 carbon
atoms. The term "lower alkenyl" intends an alkenyl group of two to
six carbon atoms, preferably two to four carbon atoms. "Substituted
alkenyl" refers to alkenyl substituted with one or more substituent
groups, and the terms "heteroatom-containing alkenyl" and
"heteroalkenyl" refer to alkenyl in which at least one carbon atom
is replaced with a heteroatom.
[0026] The term "alkynyl" as used herein refers to a branched or
unbranched hydrocarbon group typically although not necessarily
containing 2 to about 24 carbon atoms and at least one triple bond,
such as ethynyl, n-propynyl, isopropynyl, n-butynyl, isobutynyl,
octynyl, decynyl, and the like. Generally, although again not
necessarily, alkynyl groups herein contain 2 to about 12 carbon
atoms. The term "lower alkynyl" intends an alkynyl group of two to
six carbon atoms, preferably three or four carbon atoms.
"Substituted alkynyl" refers to alkynyl substituted with one or
more substituent groups, and the terms "heteroatom-containing
alkynyl" and "heteroalkynyl" refer to alkynyl in which at least one
carbon atom is replaced with a heteroatom.
[0027] The term "alkoxy" as used herein intends an alkyl group
bound through a single, terminal ether linkage; that is, an
"alkoxy" group may be represented as --O-alkyl where alkyl is as
defined above. A "lower alkoxy" group intends an alkoxy group
containing one to six, more preferably one to four, carbon atoms.
The term "aryloxy" is used in a similar fashion, with aryl as
defined below.
[0028] Similarly, the term "alkyl thio" as used herein intends an
alkyl group bound through a single, terminal thioether linkage;
that is, an "alkyl thio" group may be represented as --S-alkyl
where alkyl is as defined above. A "lower alkyl thio" group intends
an alkyl thio group containing one to six, more preferably one to
four, carbon atoms.
[0029] The term "allenyl" is used herein in the conventional sense
to refer to a molecular segment having the structure
--CH.dbd.C=CH.sub.2. An "allenyl" group may be unsubstituted or
substituted with one or more non-hydrogen substituents.
[0030] The term "aryl" as used herein, and unless otherwise
specified, refers to an aromatic substituent containing a single
aromatic ring or multiple aromatic rings that are fused together,
linked covalently, or linked to a common group such as a methylene
or ethylene moiety. The common linking group may also be a carbonyl
as in benzophenone, an oxygen atom as in diphenylether, or a
nitrogen atom as in diphenylamine. Preferred aryl groups contain
one aromatic ring or two fused or linked aromatic rings, e.g.,
phenyl, naphthyl, biphenyl, diphenylether, diphenylamine,
benzophenone, and the like. In particular embodiments, aryl
substituents have 1 to about 200 carbon atoms, typically 1 to about
50 carbon atoms, and preferably 1 to about 20 carbon atoms.
"Substituted aryl" refers to an aryl moiety substituted with one or
more substituent groups, (e.g., tolyl, mesityl and perfluorophenyl)
and the terms "heteroatom-containing aryl" and "heteroaryl" refer
to aryl in which at least one carbon atom is replaced with a
heteroatom.
[0031] The term "aralkyl" refers to an alkyl group with an aryl
substituent, and the term "aralkylene" refers to an alkylene group
with an aryl substituent; the term "alkaryl" refers to an aryl
group that has an alkyl substituent, and the term "alkarylene"
refers to an arylene group with an alkyl substituent.
[0032] The terms "halo" and "halogen" are used in the conventional
sense to refer to a chloro, bromo, fluoro or iodo substituent. The
terms "haloalkyl," "haloalkenyl" or "haloalkynyl" (or "halogenated
alkyl," "halogenated alkenyl," or "halogenated alkynyl") refers to
an alkyl, alkenyl or alkynyl group, respectively, in which at least
one of the hydrogen atoms in the group has been replaced with a
halogen atom.
[0033] The term "heteroatom-containing" as in a
"heteroatom-containing hydrocarbyl group" refers to a molecule or
molecular fragment in which one or more carbon atoms is replaced
with an atom other than carbon, e.g., nitrogen, oxygen, sulfur,
phosphorus or silicon. Similarly, the term "heteroalkyl" refers to
an alkyl substituent that is heteroatom-containing, the term
"heterocyclic" refers to a cyclic substituent that is
heteroatom-containing, the term "heteroaryl" refers to an aryl
substituent that is heteroatom-containing, and the like. When the
term "heteroatom-containing" appears prior to a list of possible
heteroatom-containing groups, it is intended that the term apply to
every member of that group. That is, the phrase
"heteroatom-containing alkyl, alkenyl and alkynyl" is to be
interpreted as "heteroatom-containing alkyl, heteroatom-containing
alkenyl and heteroatom-containing alkynyl."
[0034] "Hydrocarbyl" refers to univalent hydrocarbyl radicals
containing 1 to about 30 carbon atoms, preferably 1 to about 24
carbon atoms, most preferably 1 to about 12 carbon atoms, including
branched or unbranched, saturated or unsaturated species, such as
alkyl groups, alkenyl groups, aryl groups, and the like. The term
"lower hydrocarbyl" intends a hydrocarbyl group of one to six
carbon atoms, preferably one to four carbon atoms. "Substituted
hydrocarbyl" refers to hydrocarbyl substituted with one or more
substituent groups, and the terms "heteroatom-containing
hydrocarbyl" and "heterohydrocarbyl" refer to hydrocarbyl in which
at least one carbon atom is replaced with a heteroatom.
[0035] By "substituted" as in "substituted hydrocarbyl,"
"substituted aryl," "substituted alkyl," "substituted alkenyl" and
the like, as alluded to in some of the aforementioned definitions,
is meant that in the hydrocarbyl, hydrocarbylene, alkyl, alkenyl or
other moiety, at least one hydrogen atom bound to a carbon atom is
replaced with one or more substituents that are functional groups
such as hydroxyl, alkoxy, thio, phosphino, amino, halo, silyl, and
the like. When the term "substituted" appears prior to a list of
possible substituted groups, it is intended that the term apply to
every member of that group. That is, the phrase "substituted alkyl,
alkenyl and alkynyl" is to be interpreted as "substituted alkyl,
substituted alkenyl and substituted alkynyl." Similarly,
"optionally substituted alkyl, alkenyl and alkynyl" is to be
interpreted as "optionally substituted alkyl, optionally
substituted alkenyl and optionally substituted alkynyl."
[0036] As used herein the term "silyl" refers to the
--SiZ.sup.1Z.sup.2Z.sup.3 radical, where each of Z.sup.1, z.sup.2,
and Z.sup.3 is independently selected from the group consisting of
hydrido and optionally substituted alkyl, alkenyl, alkynyl, aryl,
aralkyl, alkaryl, heterocyclic, alkoxy, aryloxy and amino.
[0037] As used herein, the term "phosphino" refers to the group
--PZ.sup.1Z.sup.2, where each of Z.sup.1 and Z.sup.2 is
independently selected from the group consisting of hydrido and
optionally substituted alkyl, alkenyl, alkynyl, aryl, aralkyl,
alkaryl, heterocyclic and amino.
[0038] The term "amino" is used herein to refer to the group
--NZ.sup.1Z.sup.2, where each of Z.sup.1 and Z.sup.2 is
independently selected from the group consisting of hydrido and
optionally substituted alkyl, alkenyl, alkynyl, aryl, aralkyl,
alkaryl and heterocyclic.
[0039] The term "thio" is used herein to refer to the group
--SZ.sup.1, where Z.sup.1 is selected from the group consisting of
hydrido and optionally substituted alkyl, alkenyl, alkynyl, aryl,
aralkyl, alkaryl and heterocyclic.
[0040] As used herein all reference to the elements and groups of
the Periodic Table of the Elements is to the version of the table
published by the Handbook of Chemistry and Physics, CRC Press,
1995, which sets forth the new IUPAC system for numbering
groups.
[0041] This invention provides novel compounds and control agents
useful for the control of free radical polymerization reactions. In
general a free radical polymerization is carried out with these
control agents by creating a mixture of at least one polymerizable
monomer, the control agent and optionally at least one source of
free radicals, e.g., an initiator. The source of free radicals is
optional because some monomers may self-initiate upon heating.
After or upon forming the polymerization mixture, the mixture is
subjected to polymerization conditions. Polymerization conditions
are those conditions that cause the at least one monomer to form at
least one polymer, as discussed herein, such as temperature,
pressure, atmosphere, ratios of starting components used in the
polymerization mixture, reaction time or external stimuli of the
polymerization mixture.
[0042] Generally, the control agents of this invention may be
characterized by the general formula (I) above. More specifically,
the control agents of this invention may be characterized by the
general formula: 3
[0043] wherein R.sup.1 is generally any group that can easily
expelled under its free radical form (R.sup.1.) upon an
addition-fragmentation reaction, as depicted below in Scheme 1:
4
[0044] In Scheme 1, P is a free radical, typically a macro-radical,
such as polymer chain. More specifically, R.sup.1 is selected from
the group consisting of hydrocarbyl, substituted hydrocarbyl,
heteroatom-containing hydrocarbyl, and substituted
heteroatom-containing hydrocarbyl, and combinations thereof. Even
more specifically, R.sup.1 is selected from the group consisting of
optionally substituted alkyl, optionally substituted aryl,
optionally substituted alkenyl, optionally substituted alkoxy,
optionally substituted heterocyclyl, optionally substituted
alkylthio, optionally substituted amino and optionally substituted
polymer chains. And still more specifically, R.sup.1 is selected
from the group consisting of --CH.sub.2Ph,
--CH(CH.sub.3)CO.sub.2CH.sub.2CH.sub.3,
--CH(CO.sub.2CH.sub.2CH.sub.3).sub.2, --C(CH.sub.3).sub.2CN,
--CH(Ph)CN, --CH(CH.sub.3)CN, --CH.sub.2CH.sub.2CH.sub.2CH.sub.3,
and --C(CH.sub.3).sub.2Ph.
[0045] Also, R.sup.2 and R.sup.3 are each independently selected
from the group consisting of hydrogen, hydrocarbyl, substituted
hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted
heteroatom-containing hydrocarbyl, and combinations thereof. More
specifically, R.sup.2 and R.sup.3 may be each independently
selected from the group consisting of hydrogen, optionally
substituted alkyl, optionally substituted aryl, optionally
substituted alkenyl, optionally substituted acyl, optionally
substituted, aroyl, optionally substituted alkoxy, optionally
substituted heteroaryl, optionally substituted heterocyclyl,
optionally substituted alkylsulfonyl, optionally substituted
alkylsulfinyl, optionally substituted alkylphosphonyl, optionally
substituted arylsulfinyl, and optionally substituted
arylphosphonyl. Specific embodiments of R.sup.2 and/or R.sup.3 are
listed in the above definitions, and in addition include
perfluorenated aromatic rings, such as perfluorophenyl. Also
optionally, R.sup.2 and R.sup.3 can together form a ring structure,
with said ring having from 3 to 50 non-hydrogen atoms. Also
optionally, R.sup.2 and R.sup.3 are joined together to form a
double bond optionally substituted alkenyl moiety. Specific
embodiments of R.sup.2 and R.sup.3 are listed in the above
definitions.
[0046] In those embodiments where the nitrogen atom is part of a
heterocycle (i.e., R.sup.2 and R.sup.3 are joined in a ring
structure), the present invention provides increased control over
certain other control agents, such as those disclosed in U.S. Pat.
No. 6,153,705. In particular, this invention specifies that the
nitrogen in the heterocycle be directly bound to the oxygen atom.
The control agents of the present invention provide superior
control of the polymerization of vinyl monomers as compared to
those references that simply refer to any heterocycle. The degree
of control of the reaction may be reflected by a narrow molecular
weight distribution, also measured by the polydispersity index
PDI=Mw/Mn. As is known, the "living" character of the
polymerization reaction generally increases as the PDI approaches
the ideal value of 1. When the reaction proceeds and conversion
increases, usually the PDI decreases and levels off to a plateau
value. It is also well accepted that, when the PDI increases as the
conversion increases, it is a sign that some side-reaction are
taking place. In the case of the polymerization of vinyl acetate
controlled by reversible transfer agents of the xanthate type, such
a broadening of the molecular weight distribution is noticed as the
reaction proceeds (see, U.S. Pat. No. 6,153,705 example 2.34 table
8). Not wishing to be bound to theory, this effect may be due to
some deactivation of the "living" chain-ends during the course of
the reaction. This "partial" loss of control can also be
detrimental when a di-block copolymer is desired; for example, when
the first prepared polyvinylacetate block contains deactivated
chain ends and a second monomer is added, the deactivated chains do
not grow further and might "contaminate" the di-block material.
This has unwanted consequences in the use of the resultant
polymeric material in specific applications.
[0047] Some of the control agents are novel compounds. In some
embodiments, the novel compounds may be characterized by the above
formula (II). More specifically, novel compounds may be
characterized by the formula: 5
[0048] wherein R.sup.1, R.sup.2 and R.sup.3 are each as defined
above, but more specifically where R.sup.2 and R.sup.3 are
independently selected from the group consisting of alkyl,
substituted alkyl, aryl and substituted aryl.
[0049] In more specific embodiments, the groups of the novel
compounds can have R.sup.1 is selected from the group consisting of
optionally substituted alkyl, optionally substituted aryl,
optionally substituted alkenyl, optionally substituted alkoxy,
optionally substituted heterocyclyl, optionally substituted
alkylthio, optionally substituted amino and optionally substituted
polymer chains. Even more specifically, R.sup.1 is selected from
the group consisting of --CH.sub.2Ph,
--CH(CH.sub.3)CO.sub.2CH.sub.2CH.sub.3,
--CH(CO.sub.2CH.sub.2CH.sub.3).su- b.2, --C(CH.sub.3).sub.2CN,
--CH(CH.sub.3)CN, --CH.sub.2CH.sub.2CH.sub.2CH- .sub.3, --CH(Ph)CN
and --C(CH.sub.3).sub.2Ph. Also, R.sup.2 and R.sup.3 may be each
independently selected from the group consisting of hydrogen,
optionally substituted alkyl, optionally substituted aryl,
optionally substituted alkenyl, optionally substituted acyl,
optionally substituted, aroyl, optionally substituted alkoxy,
optionally substituted heteroaryl, optionally substituted
heterocyclyl, optionally substituted alkylsulfonyl, optionally
substituted alkylsulfinyl, optionally substituted alkylphosphonyl,
optionally substituted arylsulfinyl, and optionally substituted
arylphosphonyl.
[0050] Specific control agents within these formulas include: 6
[0051] This invention also includes multi-functional control agents
and their use in free radical polymerization. A multi-functional
control agent is a molecule that allows for two or more polymer
chains to polymerize from a single control agent molecule. In some
embodiments, the control agents are attached to a core that has
multiple functional sites for attachment of one portion of a
control agent. Thus, in some embodiments, R.sup.2 and/or R.sup.3
forms part of or is attached to a core molecule. In other
embodiments, R.sup.1 is part of or attached to a core molecule.
These multi-functional chain transfer agents may be characterized
by any of the following general formulas: 7
[0052] wherein Core is a core molecule, and R.sup.1, R.sup.2 and
R.sup.3 are as defined above, c is 1 or more and d is 2 or more.
Formula (IV) can be redrawn substituting R.sup.2 for R.sup.3, but
this would be redundant. Formulas (III) and (IV) include multiple
core molecules, providing many possible points from which a free
radical polymerization may be controlled. This provides the ability
to make may different architectures for polymers, some of which are
discussed below. For example, for a star architecture polymer c is
1 and d is 3 for a three arm star; c is 1 and d is 4 for a 4 arm
star; c is 1 and d is 6 for a six arm star; etc. Also for example,
for a grafted polymer, c is 1 and d is 2 for two grafts, etc. For a
hyperbranched polymer, c is 2 or more and d is 2 or more.
[0053] The multifunctional chain transfer agents may also be drawn
for the more specific embodiments of this invention, as follows:
8
[0054] The Core molecule may be selected from the group consisting
of dendritic molecules, small molecules and polymers with at least
two terminus ends. Thus, Core molecule may be optionally
substituted hydrocarbyl and optionally substituted heteroatom
containing hydrocarbyl. Specific examples of Core molecules
include: 9
[0055] In other embodiments, the Core will be a polymer chain.
These embodiments allow for the preparation of grafts or block
copolymers by attaching control agents to two or more points along
the polymer backbone or side chains or polymer termni.
[0056] In alternative embodiments, the control agents of this
invention have a ring structure, which upon ring opening may form a
multi-functional control agent. Thus, in some embodiments, R.sup.3
is deleted, and the nitrogen atom from which R.sup.3 was deleted
forms a ring with R.sup.1 providing general formula: 10
[0057] wherein the above variables have the same definitions, with
the exception that R.sup.1 is a bifunctional moiety within the
definitions given above. Note that R.sup.1 can contribute more than
one atom to the ring backbone, and thus the ring backbone can have
5, 6 or more atoms. In a particularly preferred embodiment, R.sup.1
comprises --CH(R.sup.5)--C(O)-- wherein R.sup.5 is selected from
the group consisting of hydrogen, hydrocarbyl, substituted
hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted
heteroatom-containing hydrocarbyl, and combinations thereof. In
particular, R.sup.5 is selected from the group consisting of
hydrogen, optionally substituted alkyl, optionally substituted
aryl, optionally substituted alkenyl, optionally substituted acyl,
optionally substituted, aroyl, and optionally substituted alkoxy.
Preferred R.sup.5 groups include hydrogen, methyl, ethyl, propyl,
butyl, methoxy, ethoxy, propoxy, phenoxy and phenyl.
[0058] The multifunctional chain transfer agents may also be drawn
for the more specific embodiments of this invention, as follows:
11
[0059] The control agents of this invention are synthesized,
generally, by methods known to those of skill in the art. Two
synthetic approaches are shown in the following scheme 2 and scheme
3: 12 13
[0060] For the Scheme 2 approach, the synthesis conditions
optimized for these particular nucleophiles--hydroxyamines and
their derivatives include: temperature in the range of 0.degree. C.
to ambient; solvents--acetone, acetonitrile, dioxane, DMF, DMSO;
base--sodium hydroxide, potassium hydroxide, and sodium hydride.
The preferred conditions include using sodium hydroxide as the base
in DMSO at ambient temperature.
[0061] The general procedure comprises starting with the
hydroxyamine or its derivative dissolved in DMSO in approximately a
0.5-1.0 M concentration at ambient temperature. The solution is
then treated with approximately 1 equivalent of NaOH and followed
by addition of approximately 1 equivalent of carbon disulfide. The
resulting solution is then stirred (for example, for approximately
1 hour at ambient temperature) before addition of approximately 1
equivalent of an alkylation agent.
[0062] For the Scheme 3 approach, the general procedure comprises
generating dithiocarbonyl chloride and then coupling it with
hydroxylamine, as follows. A mercaptan was treated with
approximately one equivalent of sodium hydride to form the
corresponding thiolate in anhydrous THF solvent. Subsequently, to
this reaction mixture approximately one equivalent of thiophosgen
was added and stirred for approximately one hour, then followed by
addition of approximately one equivalent of sodium
hydride-deprotonated hydroxylamine.
[0063] Work-up may comprise addition of water, extraction with
organic solvent, and drying. The desired control agent may be
purified by chromatography and/or distillation and may be
characterized by .sup.1H NMR, .sup.13C NMR, and LC/MS.
[0064] The polymerization conditions that may be used include
temperatures for polymerization typically in the range of from
about 20.degree. C. to about 110.degree. C., more preferably in the
range of from about 40.degree. C. to about 90.degree. C. and even
more preferably in the range of from about 50.degree. C. to about
80.degree. C. The atmosphere may be controlled, with an inert
atmosphere being preferred, such as nitrogen or argon. The
molecular weight of the polymer is controlled via adjusting the
ratio of monomer to control agent. Generally, the molar ratio of
monomer to control agent is in the range of from about 5 to about
5000, more preferably in the range of from about 10 to about 2000,
and most preferably from 10 to about 1500.
[0065] A free radical source is provided in the polymerization
mixture, which can stem from spontaneous free radical generation
upon heating or preferably from a free radical initiator. In the
latter case the initiator is added to the polymerization mixture at
a concentration high enough to for an acceptable polymerization
rate (e.g., commercially significant conversion in a certain period
of time, such as listed below). Conversely, a too high free radical
initiator to control agent ratio will favor unwanted dead polymer
formation through radical-radical coupling reaction leading to
polymer materials with uncontrolled characteristics. The molar
ratio of free radical initiator to control agent for polymerization
are typically in the range of from about 3:1 to about 0.02:1.
[0066] Polymerization conditions also include the time for
reaction, which may be from about 0.5 hours to about 72 hours,
preferably in the range of from about 1 hour to about 36 hours,
more preferably in the range of from about 2 hours to about 18
hours. Conversion of monomer to polymer is preferably at least
about 50%, more preferably at least about 75% and most preferable
at least about 85%.
[0067] The polymerization process generally proceeds in a "living"
type manner. Thus, generally an approximately linear relationship
between conversion and number average molecular weight can be
observed, although this is not a pre-requisite. The living
character manifests itself by the ability to prepare block
copolymers: hence, a polymer chain is first grown with monomer A,
and then, when monomer A is depleted, monomer B is added to extend
the first block of polymer A with a second block of polymer B.
Thus, in some instances, particularly when the chain transfer
constant of the control agent, Ct, is low (Ct being defined as the
ratio of the transfer rate coefficient to the propagation rate
constant), e.g., Ct less than 2, the molecular weight to conversion
plot might not exhibit a linear trend: this does not preclude
however that block copolymer formation did not occur. Block
copolymer formation through a living process can be demonstrated
using analytical techniques such as polymer fractionation with
selective solvent (of polymer A, polymer B, respectively), gradient
elution chromatography and/or 2-dimensional chromatography. Block
copolymers tend to microphase-separate and organize in a variety of
morphologies that can be probed by physical techniques such as
X-ray diffraction, dynamic mechanical testing, and the like.
[0068] Initiators, as discussed above, may be optional. When
present, initiators useful in the polymerization mixture and the
inventive process are known in the art, and may be selected from
the group consisting of alkyl peroxides, substituted alkyl
peroxides, aryl peroxides, substituted aryl peroxides, acyl
peroxides, alkyl hydroperoxides, substituted alkyl hydroperoxides,
aryl hydroperoxides, substituted aryl hydroperoxides, heteroalkyl
peroxides, substituted heteroalkyl peroxides, heteroalkyl
hydroperoxides, substituted heteroalkyl hydroperoxides, heteroaryl
peroxides, substituted heteroaryl peroxides, heteroaryl
hydroperoxides, substituted heteroaryl hydroperoxides, alkyl
peresters, substituted alkyl peresters, aryl peresters, substituted
aryl peresters, and azo compounds. Specific initiators include
benzoylperoxide (BPO) and AIBN. The polymerization mixture may use
a reaction media is typically either an organic solvent or bulk
monomer or neat. Optionally, after the polymerization is over
(e.g., completed or terminated) the thio-moiety (e.g., a
dithio-moiety) of the control agent can be cleaved by chemical or
thermal ways, if one wants to reduce the sulfur content of the
polymer and prevent any problems associated with presence of the
control agents chain ends, such as odor or discoloration. Typical
chemical treatment includes the catalytic or stoichiometric
addition of base such as a primary amine, acid or anhydride,
oxidizing agents such as hypochlorite salts, or reducing agents
such as Raney nickel.
[0069] Generally, monomers that may be polymerized using the
methods of this invention (and from which M, below, may be derived)
include at least one monomer is selected from the group consisting
of styrene, substituted styrene, alkyl acrylate, substituted alkyl
acrylate, alkyl methacrylate, substituted alkyl methacrylate,
acrylonitrile, methacrylonitrile, acrylamide, methacrylamide,
N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide,
N,N-dialkylmethacrylamide, isoprene, butadiene, ethylene, vinyl
acetate and combinations thereof. Functionalized versions of these
monomers may also be used. Specific monomers or comonomers that may
be used in this invention include methyl methacrylate, ethyl
methacrylate, propyl methacrylate (all isomers), butyl methacrylate
(all isomers), 2-ethylhexyl methacrylate, isobornyl methacrylate,
methacrylic acid, benzyl methacrylate, phenyl methacrylate,
methacrylonitrile, .alpha.-methylstyrene, methyl acrylate, ethyl
acrylate, propyl acrylate (all isomers), butyl acrylate (all
isomers), 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid,
benzyl acrylate, phenyl acrylate, acrylonitrile, styrene, glycidyl
methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl
methacrylate (all isomers), hydroxybutyl methacrylate (all
isomers), N,N-dimethylaminoethyl methacrylate,
N,N-diethylaminoethyl methacrylate, triethyleneglycol methacrylate,
itaconic anhydride, itaconic acid, glycidyl acrylate,
2-hydroxyethyl acrylate, hydroxypropyl acrylate (all isomers),
hydroxybutyl acrylate (all isomers), N,N-dimethylaminoethyl
acrylate, N,N-diethylaminoethyl acrylate, triethyleneglycol
acrylate, methacrylamide, N-methylacrylamide,
N,N-dimethylacrylamide, N-tert-butylmethacrylamide,
N-n-butylmethacrylamide, N-methylolmethacrylamide,
N-ethylolmethacrylamide, N-tert-butylacrylamide,
N-n-butylacrylamide, N-methylolacrylamide, N-ethylolacrylamide,
4-acryloylmorpholine, vinyl benzoic acid (all isomers),
diethylaminostyrene (all isomers), .alpha.-methylvinyl benzoic acid
(all isomers), diethylamino .alpha.-methylstyrene (all isomers),
p-vinylbenzene sulfonic acid, p-vinylbenzene sulfonic sodium salt,
trimethoxysilylpropyl methacrylate, triethoxysilylpropyl
methacrylate, tributoxysilylpropyl methacrylate,
dimethoxymethylsilylpropyl methacrylate, diethoxymethylsilylpropyl
methacrylate, dibutoxymethylsilylpropyl methacrylate,
diisopropoxymethylsilylpropyl methacrylate, dimethoxysilylpropyl
methacrylate, diethoxysilylpropyl methacrylate, dibutoxysilylpropyl
methacrylate, diisopropoxysilylpropyl methacrylate,
trimethoxysilylpropyl acrylate, triethoxysilylpropyl acrylate,
tributoxysilylpropyl acrylate, dimethoxymethylsilylpropyl acrylate,
diethoxymethylsilylpropyl acrylate, dibutoxymethylsilylpropyl
acrylate, diisopropoxymethylsilylpropyl acrylate,
dimethoxysilylpropyl acrylate, diethoxysilylpropyl acrylate,
dibutoxysilylpropyl acrylate, diisopropoxysilylpropyl acrylate,
maleic anhydride, N-phenylmaleimide, N-butylmaleimide, butadiene,
isoprene, chloroprene, ethylene, vinyl acetate and combinations
thereof.
[0070] In some embodiments of the polymers of this invention, a
combination of hydrophobic and hydrophilic monomers may be used,
either randomly or in separate blocks of a copolymer (e.g.,
thermoplastic elastomers, grafts, etc). The hydrophobic/hydrophilic
nature of monomers may be determined according to the log P of the
particular monomers, which is sometimes referred to as the
octanol-water partition coefficient. Log P values are well known
and are determined according to a standard test that determines the
concentration of monomer in a water/1-octanol separated mixture. In
particular, computer programs are commercially available as well as
on the internet that will estimate the log P values for particular
monomers. Some of the log P values in this application were
estimated from the web site http://esc.syrres.com/interk-
ow/kowdemo.htm, which provides an estimated log P value for
molecules by simply inserting the CAS registry number or a chemical
notation. Log P values listed herein were obtained from either the
web site listed above or from Hansch et al. Exploring QSAR:
Hydrophobic, Electronic, and Steric Constants (ACS Professional
Reference Book, 1995), which is incorporated herein by
reference.
[0071] Suitable hydrophilic monomers (with approximate log P values
listed in parentheses) may be listed above and include, but are not
limited to, acrylic acid (0.35), methacrylic acid (0.93),
N,N-dimethylacrylamide (-0.13), dimethyl aminoethyl methacrylate
(0.97), quaternized dimethylaminoethyl methacrylate, methacrylamide
(-0.26), N-t-butyl acrylamide (1.02), maleic acid (-0.48), maleic
anhydride and its half esters, crotonic acid (0.72), itaconic acid
(-0.34), acrylamide (-0.67), acrylate alcohols, hydroxyethyl
methacrylate, diallyldimethyl ammonium chloride, vinyl ethers (such
as methyl vinyl ether), maleimides, vinyl pyridine, vinyl imidazole
(0.96), other polar vinyl heterocyclics, styrene sulfonate, allyl
alcohol (0.17), vinyl alcohol (such as that produced by the
hydrolysis of vinyl acetate after polymerization), salts of any
acids and amines listed above, and mixtures thereof. Preferred
hydrophilic monomers include acrylic acid, N,N-dimethyl acrylamide
(-0.13), dimethylaminoethyl methacrylate (0.97), quaternized
dimethyl aminoethyl methacrylate, vinyl pyrrolidone, salts of acids
and amines listed above, and combinations thereof.
[0072] Suitable hydrophobic monomers may be listed above and
include, but are not limited to, acrylic or methacrylic acid esters
of C.sub.1-C.sub.18 alcohols, such as methanol, ethanol, methoxy
ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol,
1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol,
1-methyl-1-butanol, 3-methyl-1-butanol, 1-methyl-1-pentanol,
2-methyl-1-pentanol, 3-methyl-1-pentanol, t-butanol
(2-methyl-2-propanol), cyclohexanol, neodecanol, 2-ethyl-1-butanol,
3-heptanol, benzyl alcohol, 2-octanol, 6-methyl-1-heptanol,
2-ethyl-1-hexanol, 3,5-dimethyl-1-hexanol, 3,5,5-tri
methyl-1-hexanol, 1-decanol, 1-dodecanol, 1-hexadecanol, 1-octa
decanol, and the like, the alcohols having from about 1 to about 18
carbon atoms, preferably from about 1 to about 12 carbon atoms;
styrene; polystyrene macromer, vinyl acetate; vinyl chloride;
vinylidene chloride; vinyl propionate; alpha-methylstyrene;
t-butylstyrene; butadiene; cyclohexadiene; ethylene; propylene;
vinyl toluene; and mixtures thereof. Preferred hydrophobic monomers
(with approximate log P values listed in parentheses) include
n-butyl methacrylate (2.36), isobutyl methacrylate (2.66), t-butyl
acrylate (2.09), t-butyl methacrylate (2.54), 2-ethylhexyl
methacrylate (4.09), methyl methacrylate (1.38), vinyl acetate
(0.73), vinyl acetamide, vinyl formamide, and mixtures thereof,
more preferably t-butyl acrylate, t-butyl methacrylate, or
combinations thereof.
[0073] In addition, monomers that polymerize in a ring closing
method may also be used in this invention, including monomers that
are of the formula: CH.sub.2.dbd.CH--X'--CH.dbd.CH.sub.2 where X'
comprises from 1 to 20 non-hydrogen atoms. Such monomers are well
known in the art. A specific example is
{CH.sub.2.dbd.CH--N(CH.sub.3).sub.2--CH.dbd.CH.sub.2}-
.sup.+{Cl}.sup.-.
[0074] In the broadest sense, an emulsion polymerization is any
heterogeneous polymerization in an aqueous environment. Typically,
these systems produce particles of polymer as product. Those
skilled in the art recognize many variants of these heterogeneous
polymerizations, including true emulsions, micro emulsions, mini
emulsions, suspensions and dispersions. These processes are
generally distinguished by differences in process, components or
results, with specific factors including the presence, amount and
type of surfactant required; presence, amount and type of
intitiator; presence, type and amount of monomer, including monomer
solubility; polymerization kinetics; temperature; order of addition
of the components, including the timing of addition of the
components (e.g., monomer); solubility of the polymeric product;
agitation; presence of co-solvents; resulting particle size;
particle stability in the polymerization system toward coagulation
or sedimentation; and other factors known to those skilled in the
art. In some embodiments of this invention, systems that employ a
shearing force or step to create small particle sizes are
excluded.
[0075] One specifically preferred embodiment of the invention is a
controlled heterogenous polymerization reaction in an emulsion
characterized by particle sizes ranging from 20 to 1000 nm, and
preferably from 30 to 600 nm or from 40 to 300 nm. Polymerizations
of this embodiment may have process parameters similar to those
discussed above for "traditional" or "true" emulsion
polymerizations. These emulsions are stable (on the order of many
months with no observed coagulation or sedimentation), yet are
prepared using surfactant in amounts less than 3% by weight to
monomer.
[0076] The use of control agents under emulsion conditions offers
other benefits associated with living kinetics (e.g., linear
increase in molecular weight as a function of conversion). The
controlled free radical emulsion polymerizations of the invention
provide a high degree of control over molecular weight often with
narrow molecular weight distribution (polydispersity
(M.sub.W/M.sub.N) generally less than 2 and preferably between 1.1
and 1.8).
[0077] In the heterogeneous polymerization process of this
invention, the control agent is combined with water, optionally
surfactant, initiator, and at least one monomer. Polymerization
conditions include a temperature in the range of from about
25.degree. C. to about 150.degree. C., preferably between about
35.degree. C. and about 110.degree. C., more preferably between
about 40.degree. C. and about 100.degree. C., and most preferably
between about 50.degree. C. and about 90.degree. C.
[0078] Polymerization conditions also include a pressure between
about ambient pressure up to about 100 atmospheres. Polymerization
conditions also include the time for reaction, which may be from
about 0.5 hours to about 72 hours, preferably in the range of from
about 1 hour to about 36 hours, more preferably in the range of
from about 2 hours to about 18 hours.
[0079] Surfactants can be useful in the processes and composition
of this invention. Suitable surfactants include any species or
mixture of species capable of stabilizing colloidal emulsions.
Generally surfactants are amphiphilic molecules comprising both
hydrophobic and hydrophilic regions, which are capable of adsorbing
to surfaces. Surfactants may be small molecules or polymers,
micelle forming or non-micelle forming and may be anionic,
cationic, zwitterionic or nonionic. In some embodiments, it may be
desirable to use mixtures of surfactants, for example to enhance
particle stability or control particle formation. Surfactants can
play an important role in determining particle size, particle
distribution, particle formation and the stability of the resulting
polymer emulsion, which are factors that those of skill in the art
typically consider when choosing a surfactant for any specific
embodiment. Typical amounts of surfactants range from about 0.01 to
about 200% by weight relative to the monomer, with a more preferred
range being from about 0.1 to about 5% by weight and more
specifically preferred being from about 0.5 to about 3% by
weight.
[0080] Suitable surfactants include anionic, small molecule
surfactants including substituted or unsubstituted hydrocarbyl
sulfates, sulfonates, carboxylates, phosphonates and phosphates,
having between 6 and 30 carbon atoms per anionic functional group.
When the hydrocarbyl group is substituted, it may have one or more
hydrogen or carbon atoms replaced with another atom selected from
the group consisting of N, S, O, Si, F, Cl, Br and I. The
hydrocarbyl may also have one or more hydrogen or carbon atom
replaced with a functionality such as a keto, ester, amide, ether,
thioether and the like. Specific examples of anionic, non-polymeric
surfactants include sodium dodecyl sulfate, sodium dodecylbenzene
sulfonate, C.sub.14-C.sub.16 .alpha.-olefin sulfonate, oleoyl
methyltaurine, alkyl sulfosuccinate, sodium stearate, alkyl
substituted disulfonated diphenyloxide and nonylphenoxy
oligo(ethylene glycol) sulfate. Ionic polymers can be used,
including polyethyleneimine, polyacrylic acid, carboxymethyl
cellulose and the like. Suitable cationic surfactants include
cetyltrimethyl ammonium bromide, N-methyl(4-dodecylpyridinium
bromide). Suitable nonionic surfactants include ethoxylated mono-,
di- and trialkylphenols (degree of ethoxylation: 3 to 100, alkyl
radical: C.sub.4 to C.sub.12), ethoxylated fatty alcohols (degree
of ethoxylation: 3 to 100, preferably 6 to 50, alkyl radical:
C.sub.6 to C.sub.20) and alkali metal and ammonium salts of
alkylsulfates (alkyl radical: C.sub.8 to C.sub.18), of sulfuric
half-esters of ethoxylated alkanols (degree of ethoxylation: 1 to
70, in particular 2 to 10, alkyl radical: C.sub.10 to C.sub.18) and
of ethoxylated alkylphenols (degree of ethoxylation: 3 to 100,
preferably 6 to 50, alkyl radical: C.sub.4 to C.sub.18) and alkali
metal and ammonium salts of alkanesulfonic acids (alkyl radical:
C.sub.10 to Cl.sub.18) and of alkylarylsulfonic acids (alkyl
radical: C.sub.9 to Cl.sub.18). Further suitable surfactants, such
as sulfosuccinates, are described in Houben-Weyl, Methoden der
organischen Chemie, Volume XIV/1, Makromolekulare Stoffe,
Georg-Thieme Verlag, Stuttgart, 1961, pages 192 to 208. Alternative
surfactants include functional monomers, polymerizable surfactants
and water-soluble surface-active polymers, including block
copolymers, such as polyethyleneoxide-b-polypropyleneoxid-
e-b-polyethyleneoxide (Pluronic.RTM.). Specific examples include
polyvinyl alcohols, cellulose derivatives or
vinylpyrrolidone-containing copolymers. A detailed description of
further suitable protective colloids is given in Houben-Weyl,
Methoden der organischen Chemie, Volume XIV/1, Makromolekulare
Stoffe, Georg-Thieme-Verlag, Stuttgart, 1961, pages 411 to 420.
Currently commercially available surfactants that are useful in
this invention are listed below in Table 1.
1TABLE 1 Trade Name Supplier Contents Ionics Abex VA-50 Rhodia 46%;
1:1 mix of anionic and ethoxylated octyl phenol Abex 2020 Rhodia
Anionic/non-ionic mix (APE free), 30% Abex 2030 Rhodia
Anionic/non-ionic mix (APE free), 30% Abex 18-S Rhodia Na Ether
Sulfates; APE-free, 35% Abex 12-S Rhodia Na Ether Sulfates;
APE-free, 30% Aerosol OT Sigma [(Bis-2-ethylhexyl)sodium
sulfosuccinate, C.sub.20H.sub.37O.sub.7S.Na, M.sub.w 444.6, 10%
Aerosol 22 Sigma [(Bis-2-ethylhexyl)sodium sulfosuccinate,
C.sub.20H.sub.37O.sub.7S.Na, M.sub.w 444.6, neat d = 1.12 Calfax
DB-45 Pilot Chemical C.sub.12(branched) Sodium diphenyloxide
disulfonate, 45% Calfax 16L-35 Pilot Chemical C.sub.16(linear)
Sodium diphenyloxide disulfonate, 35% Calimulse L-30 Pilot Chemical
Sodium linear alkyl benzene sulfonate 30% Calimulse EM-30 Pilot
Chemical Sodium branched dodecyl benzene sulfonate 30% Calsoft F-90
Pilot Chemical Sodium linear alkyl benzene sulfonate, solid, 90 + %
Dowfax C6L Dow Disulfonated diphenyloxide with C.sub.6 backbone
Dowfax CI0L Dow Disulfonated diphenyloxide with C.sub.10 backbone
Dowfax 8390 Dow Disulfonated diphenyloxide with C.sub.16 backbone,
45% Emulgator 825 BASF anionic/non-ionic mix Emulgator 825-S BASF
anionic/non-ionic mix Rhodacal A-246/L Rhodia sodium alpha C14-C16
olefin sulfonate (38-41%) Rhodacal DS-4 Rhodia sodium dodecyl
benzene sulfonate 23% SDS Aldrich sodium dodecyl sulfate SDBS
Aldrich sodium dodecyl benzene sulfonate 90% Triton QS-30 Union
Carbide 90%, gel like Triton X-200 Union Carbide 28% aq dispersion
Atphos 3232 ICI Polyoxyethylene phosphate ester Atphos 3226 ICI
anionic sfac, phosphoric acid Atphos 3202 ICI NonylPE n = 6, acid
form, 100% Nonionics Abex 2545 Rhodia Abex 2535 Rhodia Dynol 604
Air Products Ethoxylated acetylenic diols, 100% Igepal CO-210
Aldrich APE
(C.sub.9H.sub.19-C.sub.6H.sub.4-(OCH.sub.2CH.sub.2).sub.2OH) 100%
Igepal CO-520 Aldrich APE
(C.sub.9H.sub.19-C.sub.6H.sub.4-(OCH.sub.2CH.su- b.2).sub.5OH) 100%
Igepal CA-897 Rhodia APE (octylphenol ethoxylate) 70%, n = 40
Igepal CO-897 Rhodia APE (nonylphenol ethoxylate) 70% n = 40
Pluronic F38 BASF EO-PO-EO block, average M.sub.w 4700 HLB 31
Pluronic F98 BASF EO-PO-EO block, average M.sub.w 13K, HLB 28
Pluronic P65 BASF EO-PO-EO block, average M.sub.w 3400 HLB 17
Surfynol 104 PA Air Products 50% in isopropyl alcohol, 50%
2,4,7,9-tetramethyl-5-decyne-4,7,-diol Surfynol 104 PG-50 Air
Products 50% in propylene glycol, 50% 2,4,7,9-tetramethyl-5-dec-
yne-4,7,-diol Surfynol DF-58 Air Products silicone-based Surfynol
440 Air Products Surfynol 104 with ethylene oxide chains, more
hydrophilic, 100% Surfynol 465 Air Products Surfynol 104 with
ethylene oxide chains, more hydrophobic, 100% Triton X-100 Union
Carbide t-octylphenoxy-polyethoxyethanol (n = 9.5), 100% Triton
X-405 Union Carbide t-octylphenoxy-polyethoxyethanol, 70%
[0081] The process of the invention does not necessarily require
surfactant. For example, surfactant-free recipes can be used where
the sulfate groups on a persulfate initiator impart the latex
stability. In this case, relatively large ratios of initiator to
monomer are used (e.g., 50:1 to 250:1) and large particles result
(e.g., 300-600 nm). The ratios of components (e.g., initiators,
surfactants, monomers, and control agents) in the polymerization
mixture may be important and can vary widely depending on the
particular application. The ratio of monomer to control agent can
be used to determine the molecular weight of polymers produced
using the controlled heterogeneous free radical polymerization
processes of the invention. According to these processes, the
number average molecular weight of the resulting polymers depends
linearly on the number of control agents in the polymerization and
the mass of monomer.
[0082] In some embodiments, the monomer to initiator ratio may be
in the range of from about 10:1 to about 10,000:1, more preferably
the range of from about 50:1 to about 10,000:1 and most preferably
the range of from about 100:1 to about 5000:1. Another ratio that
may be controlled is the ratio of equivalents of initiator to
control agent, (with the assumption that the amount of initiator is
approximately equivalent to the number of radical produced), which
is typically in the range of from about 1:0.1 to about 1:10, more
preferably the range of from about 1:0.3 to about 1:5 and most
preferably the range of from about 1:0.4 to about 1:2. When a redox
system is used, it may be present the ratio of initiator to
reductant typically in the range of from about 1:0.1 to about 1:4,
more preferably the range of from about 1:0.3 to about 1:2 and most
preferably the range of from about 1:0.4 to about 1:1.6. The
surfactant to monomer ratio may be controlled and is typically in
the range of from about 0.0001 to about 2:1, more preferably the
range of from about 0.001:1 to about 0.05:1 and most preferably the
range of from about 0.001:1 to about 0.02:1 (although for some
emulsions there may be no surfactant added at all where other
reaction components perform that function). The percent solids may
be in the range of from 0.001% to about 90% by volume. In some
preferred applications, the novel aqueous polymer emulsions are
produced with a solids content of =40%, advantageously =50%, by
volume, based on the total aqueous polymer emulsion. The useful
solids content for other applications is from 0.5 to 75% by volume.
The preparation of the novel aqueous polymer emulsions is carried
out according to the product by process definition of the subject
according to the invention, as stated at the outset, i.e., by the
free radical aqueous emulsion polymerization method in the presence
of surface active materials and free radical polymerization
initiators. The ratio of the aqueous phase to the total amount of
the monomers used in both stages is chosen according to the desired
solids content of the aqueous polymer emulsion to be prepared.
[0083] The emulsion process can be implemented in a batch,
semi-batch or continuous mode. In one embodiment the reaction is
operated in such a way as to convert the control agent into dormant
chains early in the process. For example, the consumption of the
control agent is substantially completed when the cumulative
monomer conversion (defined as the ratio monomer converted at time
t to the total monomer present in the recipe) is less than about
30%, more specifically less than about 20% and even more
specifically less than about 10%. This can be performed by
adjusting polymerization process variables, such as the sequence
and feed-rate of addition of monomers, control agents, initiators,
etc. For example, in a semi-batch polymerization process where a
fraction of the monomer is introduced initially in the reactor and
the remaining fraction fed over a period of time, the control agent
is preferentially added in totality in the initial charge. In a
continuous polymerization process (e.g., using either a
recirculation loop or a series of continuously stirred tank
reactors), the control agent is preferably fed in the upstream part
of the continuous process. A preferred polymerization process is
semi-batch, with the totality of the control agent fed to the
initial charge and where the feed rate of the monomer stream is
adjusted to a "starved feed regime", i.e., where the monomer to
polymer ratio is maintained below 0.2, preferably 0.05, until the
control agent is totally consumed (as measured by gas or liquid
chromatography). Process variables that may coincide to control the
monomer to polymer ratio are rate of monomer additions, initiator
to monomer ratios, temperature and particle size.
[0084] A free radical source is provided in the polymerization
mixture, which can stem from spontaneous free radical generation
upon heating or preferably from a free radical initiator. In the
latter case the initiator is added to the polymerization mixture at
a concentration high enough to for an acceptable polymerization
rate (e.g., commercially significant conversion in a certain period
of time, such as listed below). Conversely, a too high free radical
initiator to control agent ratio will favor unwanted dead polymer
formation through radical-radical coupling reaction leading to
polymer materials with uncontrolled characteristics. The molar
ratio of free radical initiator to control agent for polymerization
are typically in the range of from about 2:1 to about 0.02:1.
[0085] The polymers formed with the chain transfer agents of this
invention are believed to be grown via a degenerative transfer
mechanism. Thus, upon analysis of the obtained polymers, monomers
might appear between the R.sup.1--S bond, and any of the above
formulas can be rewritten in a polymeric form. For example, the
polymers of this invention may be characterized by the general
formula: 14
[0086] wherein M is a monomer or mixture of monomers or at least 2
blocks of different monomer (any from the above lists) and f is the
degree of polymerization, and R.sup.1, R.sup.2 and R.sup.3 are as
defined above.
[0087] Free radical polymerization of cyclic monomers by ring
opening mechanism is known (see, e.g., The Chemistry Of Free
Radical Polymerization, G. Moad, D. H. Solomon, Eds. (Pergamon
Pub., 1995), p 176-183). However no commercially viable process has
been developed so far. This is due at least in part to the poor
reactivity of these monomer compounds (e.g., Ketene acetals) as
well as their relative instability to water traces. Moreover, known
polymerization mechanisms for ring opening polymerization systems
are not know for their living-type kinetics.
[0088] The cyclized forms of the multi-functional control agents
(such as those described by formulas (V)) typically lead to ring
opening reaction under polymerization conditions. The polymer thus
formed may be characterized by the general formula: 15
[0089] where R.sup.2 and R.sup.5 have the same definitions given
above and A represents a repeat unit of block of monomer A (with n"
being the degree of polymerization of the block; m" being the
number of repeat units of the block with the attached control
agent; and * representing the ends of the polymer). The molecular
weight of the polymer formed from monomer A is generally controlled
by controlling the monomer to control agent ratio in the
polymerization mixture, as discussed above.
[0090] As formula (VII) shown, the multi-functional control agents
of this invention also provide, in some embodiments, for a compound
(i.e., N--OC(.dbd.S)S) in the backbone of a carbon-carbon polymer
chain, such as usually obtained by free radical polymerization of
ethylenic monomers. This is desirable for several applications: for
instance, such polymers can be reduced to low molecular weight
material by applying external stimuli such as UV, light, heat,
biochemical or chemical treatment, which are known to cleave
thiocarbonylthio linkage. Such polymers could be used as
thermoplastics susceptible to degradation by exposure to sunlight,
or by enzymatic digestion since it is known that short polymers
chains are readily biodegradable.
[0091] Moreover, multiblock copolymers (ABx).sub.y can be obtained
in a two-step process, by first preparing a first multiblock
homopolymer, denoted (Ax).sub.y, where x represents the
N--OC(.dbd.S)S moiety and y represents the number of A or AB blocks
and y is 2 or more, and then adding monomer B, in order to get
(ABx).sub.y, which may be characterized by the general formula:
16
[0092] where R.sup.2 and R.sup.5 and n" and m" have the same
definitions given above, A represents a repeat unit of block of
monomer A and B represents a repeat unit of block of monomer B and
o" is the degree of polymerization of monomer B. Monomers A and B
can be selected from any of the above lists. Copolymers having a
similar structure as (AB).sub.y copolymers are usually prepared by
multiple sequential addition of different monomers with the usual
pitfalls such as loss of control as long as the number of block
increase or contamination of block A with B monomers. This new
process alleviates these difficulties.
[0093] The formulas for multifunctional control agents can also be
written in polymer form, as follows: 17
[0094] wherein each of the variable in formulas (IX) to (X) have
the meanings that are stated above.
[0095] In some embodiments of this invention, it is desirable to
make a block copolymer, such as for example with both hydrophobic
and hydrophilic monomers, with these monomers being selected from
the above lists. In this case, the monomers M in the above formulas
will be A and B or more blocks.
[0096] As used herein, "block copolymer" refers to a polymer
comprising at least two segments of differing composition; having
any one of a number of different architectures, where the monomers
are not incorporated into the polymer architecture in a solely
statistical or uncontrolled manner. Although there may be three,
four or more monomers in single block-type polymer architecture, it
will still be referred to herein as a block copolymer. In some
embodiments, the block copolymer will have an A-B architecture
(with "A" and "B" representing the monomers). Other architectures
included within the definition of block copolymer include A-B-A,
A-B-A-B, A-B-C, A-B-C-A, A-B-C-A-B, A-B-C-B, A-B-A-C (with "C"
representing a third monomer), and other combinations that will be
obvious to those of skill in the art. Block copolymers can be
prepared a number of ways, including sequential addition of
monomers or using multi-functional control agents described above.
Of course with multi-functional control agents, the control agent
may form a linking group between one or more blocks of the
copolymers.
[0097] In another embodiment, the block copolymers of this
invention include one or more blocks of random copolymer together
with one or more blocks of single monomers. Thus, a polymer
architecture of A-R, A-R-B, A-B-R, A-R-B-R--C, etc. is included
herein, where R is a random block of monomers A and B or of
monomers B and C. Moreover, the random block can vary in
composition or size with respect to the overall block copolymer. In
some embodiments, for example, the random block R will account for
between 5 and 80% by weight of the mass of the block copolymer. In
other embodiments, the random block R will account for more or less
of the mass of the block copolymer, depending on the application.
Furthermore, the random block may have a compositional gradient of
one monomer to the other (e.g., A:B) that varies across the random
block in an algorithmic fashion, with such algorithm being either
linear having a desired slope, exponential having a desired
exponent (such as a number from 0.1-5) or logarithmic. The random
block may be subject to the same kinetic effects, such as
composition drift, that would be present in any other radical
copolymerization and its composition, and size may be affected by
such kinetics, such as Markov kinetics. Any of the monomers listed
elsewhere in this specification may be used in the block copolymers
of this invention.
[0098] A "block" within the scope of the block copolymers of this
invention typically comprises about 10 or more monomers of a single
type (with the random blocks being defined by composition and/or
weight percent, as described above). In preferred embodiments, the
number of monomers within a single block is about 15 or more, about
20 or more or about 50 or more. However, in an alternative
embodiment, the block copolymers of this invention include blocks
where a block is defined as two or more monomers that are not
represented elsewhere in the copolymer. This definition is intended
to encompass adding small amounts of a second monomer at one or
both ends of a substantially homopolymeric polymer. In this
alternative embodiment, the same copolymer architectures discussed
above apply. This definition is therefore intended to include
telechelic polymers, which include one or more functional end
groups capable of reacting with other molecules. Thus, generally, a
telechelic polymer is a block copolymer with in the definitions of
this invention. The functional groups present at one or both ends
of a telechelic polymer may be those known to those of skill in the
art, including, for example, hydroxide, aldehyde, carboxylic acid
or carboxylate, halogen, amine and the like, which have the ability
to associate or form bonds with another molecule. Likewise, the
block copolymers of the invention are intended to encompass
telechelic polymers containing bifunctional groups, such as
allyl-terminated or vinyl-terminated telechelics, sometimes
referred to as macromonomers or macromers because of their ability
to participate in polymerization reactions through the terminal
functional group.
[0099] Combining the above embodiments provides a particularly
powerful method of designing block copolymers. For example, a block
copolymer may have the architecture F-A-B-F, where F represents
functional groups that may be the same or different within a single
F-A-B-F structure (which, therefore, may encompass F-A-B-F'). Other
block copolymer architectures within the scope of this invention
include A-R-B-F and F-A-R-B-F. Other architectures will be apparent
to those of skill in the art upon review of this
specification--indeed, without wishing to be bound by any
particular theory--it is the living nature of the emulsions of this
invention that provide the ability to even make these novel block
copolymers.
[0100] In one embodiment, block copolymers are assembled by the
sequential addition of different monomers or monomer mixtures to
living polymerization reactions. In another embodiment, the
addition of a pre-assembled functionalized block (such as a
telechelic oligomer or polymer) to a living free radical
polymerization mixture yields a block copolymer. Ideally, the
growth of each block occurs to high conversion. Conversions are
determined by size exclusion chromatography (SEC) via integration
of polymer to monomer peak. For UV detection, the polymer response
factor must be determined for each polymer/monomer polymerization
mixture. Typical conversions can be 50% to 100% for each block.
Intermediate conversion can lead to block copolymers with a random
copolymer block separating the two or more homopolymer blocks,
depending on the relative rates of polymerization and monomer
addition. At high conversion, the size of this random block is
sufficiently small such that it is less to affect polymer
properties such as phase separation, thermal behavior and
mechanical modulus. This fact can be intentionally exploited to
improve polymerization times for many applications without
measurably affecting the performance characteristics of the
resulting polymer. This is achieved by intentionally "killing" or
terminating the living nature of the polymerization when a desired
level of conversion (e.g., >80%) is reached by neutralizing the
control agent, for example by introducing acids, bases, oxidizing
agents, reducing agents, radical sources, scavengers, etc. In the
absence of control agent, the polymerization continues uncontrolled
(typically at much higher reaction rates) until the remaining
monomer is consumed. Block copolymer can also be created by
grafting monomers, monomer mixtures, oligomers or polymers only
polymers having multiple available functional groups.
[0101] In other embodiments, block copolymers can be prepared by
grafting processes, preparation of telechelic polymers, preparation
of macromonomers, etc. In these embodiments, at least one polymer
segment is derived from a living or controlled process of the
invention, while other segments can be derived from any
polymerization process, including, for example, controlled or
uncontrolled radical polymerization, condensation polymerization,
Ziegler-Natta and related processes, Ring-Opening Metathesis
Polymerization, ionic polymerization, surface modification or
grafting, or other addition or step growth processes.
[0102] Block copolymers allow the combination of potentially
diverse polymer properties (such as hard/soft and/or
hydrophilic/hydrophobic (amphiphilic) blocks) into a single polymer
chain. Hard/soft block copolymers combine segments with
significantly different glass transition temperatures T.sub.g. A
typical hard/soft copolymer pairs a relatively "hard" block (e.g.,
styrene) with a relatively "soft" block (e.g., butyl acrylate). The
resulting materials can possess performance attributes not found in
any of the constituent segments. The presence of microphase
separation and various phase morphologies in block copolymers is
associated with unique performance attributes of many block
copolymers. For example, by combining the stiffness or rigidity
characteristic of hard materials with the compliance of soft
materials, block copolymers may exhibit advantageous properties,
such as processability under melt conditions, elasticity,
resistance to abrasion and cracking and desired creep
characteristics (corresponding to the material's ability to hold
its shape under external stresses) depending on morphology, making
them appropriate for use as extrudable bulk materials, coatings and
separation media. The exact properties of a hard/soft copolymer
depend significantly on the difference between the glass transition
temperatures of the constituent blocks; accordingly, selection of
monomers having glass transition temperatures a particular distance
apart can lead to hard/soft block copolymers having particular
desired characteristics. Thus, while for one application it may be
appropriate to combine blocks having glass transition temperatures
that differ by, for example, 20.degree. C., the choice of T.sub.g
(and therefore of materials) depends on the application.
[0103] Likewise, the amphiphilic block copolymers produced
according to the invention display combinations of hydrophobic and
hydrophilic properties that make such materials appropriate for use
as surfactants or dispersants, scavengers, surface treatments and
the like. Different block sizes over all ratios of monomers and
molecular weights lead to families of novel compounds, for example
thermoplastics, elastomers, adhesives, and polymeric micelles.
[0104] Multi-arm or star polymers can be generated using initiators
capable of initiating multiple free radical polymerizations under
the controlled conditions of the invention. Such initiators
include, for example polyfunctional chain transfer agents,
discussed above. Following initiation, the growth of each arm is
controlled by the same living kinetics described for linear
polymers, making it possible to assemble star polymers whose arms
include individual homopolymers as well as di, tri or higher order
block copolymers. Alternatively, multi-arm polymers are formed by
growing end-functionalized oligomers or polymers followed by the
addition of a cross-linking monomer such as ethylene glycol
diacrylate, divinyl benzene, methylene bisacrylamide, trimetylol
propane triacrylate, etc. The small hydrodynamic volume of star
polymers produced according to these methods provides properties
such as low viscosity, high M.sub.W, and high functionality useful
in applications such as rheology control, thermosets, and
separation media. Similarly, the inclusion of branched or multiple
ethylenically unsaturated monomers enables the preparation of graft
polymers, again exhibiting the living kinetics characteristic of
this invention. The existence of a block copolymer according to
this invention is determined by methods known to those of skill in
the art, including nuclear magnetic resonance (NMR), measured
increase of molecular weight upon addition of a second monomer to
chain-extend a living polymerization of a first monomer, microphase
separation (e.g., long range order, microscopy and/or birefringence
measurements), mechanical property measurements, (e.g., elasticity
of hard/soft block copolymers), thermal analysis and chromatography
(e.g., absence of homopolymer).
EXAMPLES
[0105] General: All reactions were performed in oven-dried
glassware under a positive pressure of argon or nitrogen gas. The
air- and moisture-sensitive solutions were transferred by means of
a syringe into the rubber-septum-capped reaction vessels. Reaction
mixtures and chromatographically collected fractions were
concentrated on a rotary evaporator (ca. 20.degree. C./20 torr).
Commercial grade reagents were used without further purification,
except for monomers, which were degassed by applying a nitrogen- or
argon-stream for 30 min. Monomer inhibitors were removed by
distillation or filtration over Aldrich-inhibitor-remover
[9003-70-07]. Polymerization mixtures were carried out and sealed
in a glove box under a nitrogen or argon atmosphere, and performed
at 60.degree. C. Size Exclusion Chromatography (SEC) was performed
using automated GPC systems and different sets of columns and
eluents depending on the polarity of the polymers, see Table 2 for
the details. In general, SEC was performed in accord with U.S. Pat.
Nos. 6,296,771, 6,294,338, 6,265,226, 6,260,407 and 6,175,409, each
of which is incorporated herein by reference. Molecular weight and
polydispersity index (PDI) are referred to linear polystyrene
standards.
2TABLE 2 Polymer Column Eluent Standard Detector Polystyrene PLgel
10.mu.m 10.sup.3.ANG., 300 .times. 7.5 mm + THF PS (THF) RI,
Polybutyl acrylate PLgel 10.mu.m 10.sup.4.ANG., 300 .times. 7.5 mm
+ UV Polyvinyl acetate PLgel 10.mu.m 10.sup.5.ANG., 300 .times. 7.5
mm + (290 nm) Polyvinyl- PLgel 5.mu.m Mixed-C, 300 .times. 7.5 mm
dodecanoate Poly-1-vinyl-2- 3 .times. PLgel 10 .mu.m Mixed-B, DMF +
0.1% PS ELSD pyrrolidinone 300 .times. 7.5 mm TFA (Toluene)
Polyvinyl TSK-Gel G4000PW.sub.XL, 300 .times. 7.8 mm H.sub.2O. +
0.1% None RI-LS formamide NaNO.sub.3
[0106] Monomer conversion was determined by .sup.1H-NMR on a
Brucker AC 400 (400 MHz) or by GC on a HP-6890 automated
system.
Example 1
[0107] 18
[0108] A 100-mL, two-necked, round-bottomed flask was equipped with
an inlet adapter for argon or nitrogen gas and a rubber septum. It
was charged with 10 mL of dry DMSO and sodium hydroxide (449 mg,
11.2 mmol), and subsequently diethyl hydroxylamine C'-1 (1.00 g,
11.2 mmol) was administered dropwise by means of a syringe. After
30 min. stirring at room temperature (ca.20.degree. C.), carbon
disulfide (854 mg, 11.2 mmol) was added dropwise by means of a
syringe over a period of 1 min and stirred for 30 min. Then, the
reaction was treated with ethyl 2-bromo-propionate (2.03 g, 11.2
mmol). The resulting reaction mixture was stirred for 12 h and then
quenched with 40 mL ice/water. After 5 min, the reaction was
extracted with ethyl ether (3.times.20 mL), the combined organic
phases were dried over MgSO.sub.4, filtered, and concentrated (ca.
20.degree. C./20 torr). The residue was purified by silica-gel
chromatography (hexane:AcOEt, 5:1) to yield 1.70 g of C-1 (83%) as
light yellow oil.
Example 2
[0109] 19
[0110] A 250-mL, two-necked, round-bottomed flask was equipped with
an inlet adapter for argon or nitrogen gas and a rubber septum. It
was charged with 50 mL of dry THF and sodium hydride (286 mg, 11.9
mmol), and subsequently N-benzyl-N-phenyl hydroxylamine C'-1 (2.16
g, 10.9 mmol) in 10 mL THF was administered dropwise by means of a
syringe. After 30 min stirring at room temperature (ca.20.degree.
C.), the reaction mixture was transferred dropwise into a
septum-capped, 250 mL, two-necked, round-bottomed flask charged
with dithiochloroformiate C2' by means of a syringe and
syringe-pump over a period of 30 min. The resulting reaction
mixture was stirred for 12 h and then quenched with a saturated
solution of ammonium chloride aqueous (50 mL). After 5 min, the
reaction was extracted with ethyl ether (3.times.50 mL), the
combined organic phases were dried over MgSO.sub.4, filtered, and
concentrated (ca. 20.degree. C./20 torr). The residue was purified
by silica-gel chromatography using the following
hexane:dichloromethane eluent gradient (100:0, 75:25, 50:50, 25:75,
0:100) to give 1.41 g of starting material C'-1 (35% conversion)
and 1.30 g of product C-1 (99% yield) as light yellow oil.
Examples 3-51
[0111] These examples demonstrate the controlled polymerization of
vinyl acetate (VA), vinyl pyrrolidone (VP), vinyl formamide (VF),
vinyl dodecanoate (VD), styrene (Sty) and butyl acrylate (BA) using
the control agents of this invention. Each polymerization was
carried out in the same way, a microtiter plate 1 mL vial was
charged with control agent, initiator (AIBN) and neat monomer (3.00
mmol) at room temperature (ca. 25.degree. C.). Control agent and
initiator ratios were varied as indicated in Table 3. For example,
for a degree of polymerization (DP) of 200 with 25% initiator, 3.00
mmol of monomer, 0.015 mmol of control agent and
1.8.times.10.sup.-3 mmol of initiator were used. The mixture was
then sealed and brought to the reaction temperature 60.degree. C.
and let it react for different reaction times. Samples were allowed
to cold down to room temperature and then analyzed by GPC and GC or
.sup.1H-NMR. Results are reported in Table 4, below. 20
3TABLE 3 Control Initiator Temp. Time Example Agent Monomer DP (%)
(.degree. C.) (h) 3 CA-1 VA 200 20 60 5 4 CA-1 VA 200 20 60 8 5
CA-1 VA 200 20 60 12 6 CA-1 VA 200 20 60 21 7 CA-1 VA 600 20 60 8 8
CA-1 VA 600 20 60 12 9 CA-1 VA 600 20 60 21 10 CA-1 VA 600 20 60 45
11 CA-2 VA 200 20 60 2 12 CA-2 VA 200 20 60 5 13 CA-2 VA 200 20 60
8 14 CA-2 VA 200 20 60 12 15 CA-2 VA 200 20 60 21 16 CA-3 Sty 200
25 60 9 17 CA-3 Sty 200 25 60 18 18 CA-3 Sty 200 75 60 9 19 CA-3
Sty 200 75 60 18 20 CA-3 BA 200 25 60 9 21 CA-3 BA 200 25 60 18 22
CA-3 BA 200 75 60 9 23 CA-3 BA 200 75 60 18 24 CA-3 VA 200 25 60 18
25 CA-3 VA 200 75 60 9 26 CA-3 VA 200 75 60 18 27 CA-4 VA 200 25 60
6 28 CA-4 VA 200 25 60 12 29 CA-4 VA 200 25 60 18 30 CA-4 VA 200 25
60 24 31 CA-4 VA 200 25 60 45 32 CA-4 VP 200 25 60 6 33 CA-4 VP 200
25 60 12 34 CA-4 VP 200 25 60 18 35 CA-4 VP 200 25 60 24 36 CA-4 VP
200 25 60 45 37 CA-4 VD 200 25 60 6 38 CA-4 VD 200 25 60 12 39 CA-4
VD 200 25 60 18 40 CA-4 VD 200 25 60 24 41 CA-4 VD 200 25 60 45 42
CA-4 VF 200 25 60 1 43 CA-4 VF 200 25 60 1.5 44 CA-4 VF 200 25 60 2
45 CA-4 VF 200 25 60 3 46 CA-4 VF 200 25 60 4 47 CA-4 VF 200 25 60
6 48 CA-4 VF 200 25 60 12 49 CA-4 VF 200 25 60 18 50 CA-4 VF 200 25
60 24 51 CA-4 VF 200 25 60 45
[0112]
4TABLE 4 Results Control Time Conversion Example Agent Monomer (h)
(%) Mn PDI 3 CA-1 VA 5 16 5965 1.83 4 CA-1 VA 8 34 7139 1.8 5 CA-1
VA 12 63 5831 1.75 6 CA-1 VA 21 83 13880 1.48 7 CA-1 VA 8 56 17315
1.89 8 CA-1 VA 12 81 23620 1.86 9 CA-1 VA 21 93 34723 1.8 10 CA-1
VA 45 94 38387 1.76 11 CA-2 VA 2 72 7724 1.5 12 CA-2 VA 5 83 10621
1.56 13 CA-2 VA 8 92 16802 1.5 14 CA-2 VA 12 >95 14255 1.49 15
CA-2 VA 21 >95 14931 1.48 16 CA-3 Sty 9 13 44485 1.74 17 CA-3
Sty 18 17 58736 1.73 18 CA-3 Sty 9 35 42216 1.8 19 CA-3 Sty 18 45
49764 1.92 20 CA-3 BA 9 90 30028 1.86 21 CA-3 BA 18 >99 29313
2.04 22 CA-3 BA 9 >99 27705 1.95 23 CA-3 BA 18 >99 48245 1.73
24 CA-3 VA 18 8 2713 1.81 25 CA-3 VA 9 36 8560 1.74 26 CA-3 VA 18
68 8905 1.56 27 CA-4 VA 6 44 8300 1.6 28 CA-4 VA 12 90 14500 1.47
29 CA-4 VA 18 96 26100 1.38 30 CA-4 VA 24 96 17700 1.39 31 CA-4 VA
45 96 26800 1.4 32 CA-4 VP 6 23 11280 1.13 33 CA-4 VP 12 24 11500
1.15 34 CA-4 VP 18 27 13150 1.17 35 CA-4 VP 24 29 14000 1.19 36
CA-4 VP 45 37 15200 1.21 37 CA-4 VD 6 6 8000 1.32 38 CA-4 VD 12 12
9350 1.35 39 CA-4 VD 18 25 11600 1.52 40 CA-4 VD 24 29 15500 1.52
41 CA-4 VD 45 37 13000 1.6 42 CA-4 VF 1 4 11872 1.12 43 CA-4 VF 1.5
10 19197 1.3 44 CA-4 VF 2 29 32754 1.44 45 CA-4 VF 3 47 34581 1.44
46 CA-4 VF 4 59 32109 1.48 47 CA-4 VF 6 77 34268 1.6 48 CA-4 VF 12
83 34767 1.63 49 CA-4 VF 18 83 35967 1.64 50 CA-4 VF 24 8 33739
1.64 51 CA-4 VF 45 88 33262 1.64
[0113] All these results show unambiguously that the control agents
provide a living character to the radical polymerization of most
common monomers and in particular vinylic monomers such as vinyl
acetate, vinyl formamide, vinyl pyrrolidone and vinyl
dodecanoate.
Examples 52-63
[0114] In the following examples vinyl acetate was polymerized in
bulk with AIBN as an initiator at 10 mo-% based on the monomer, and
the monomer to control agent ratio is 200:1. Temperature is fixed
at 60.degree. C. The experimental conditions are the same as the
described in Example 3, above. Examples 52-55 are comparative
examples where the control agent is a xanthate of formula
CH(CH3)(CO2Et)S--C(.dbd.S)OEt taught in U.S. Pat. No. 6,153,705. In
example 56-59 and 60-63, the control agent were CA-1 and CA-2,
respectively. The results are shown in Table 5, below:
5TABLE 5 Example Control agent Conversion (%) Mn Mw PDI 52 Xanthate
17 3132 3790 1.21 53 Xanthate 59 10277 13360 1.3 54 Xanthate 78
14614 21483 1.47 55 Xanthate 90 16620 26426 1.59 56 CA-1 16 5965
10916 1.83 57 CA-1 34 7139 12850 1.8 58 CA-1 63 5831 10204 1.75 59
CA-1 83 13880 20542 1.48 60 CA-2 56 8376 14490 1.73 61 CA-2 71 9270
15203 1.64 62 CA-2 80 9680 14520 1.5 63 CA-2 87 13548 19238
1.42
[0115] These examples show that the polydispersity index steadily
increases as reaction proceeds in the case of the xanthate control
agent, in contrast with the trend observed in examples 56-63 with
the control agents of the invention.
Examples 64-111
[0116] These examples demonstrate the use of the control agents of
the invention to control the polymerization of vinyl acetate in an
emulsion process.
[0117] Polymerizations were carried out in semi-continuous process
where vinyl acetate (90 mg, 90% of total monomer) and initiator
(90% of total initiator) were in the continuous charge. Xanthate
and CT-4 control agents (both at 0.5 mole % to monomer) were used
for comparison. The total volume of polymerization was 3 mL in a
total 30% solid concentration. The initial charges contained vinyl
acetate (100 mg), sodium acetate as buffer in 0.5 wt % to monomer,
sodium dodecyl sulfate (SDS) as surfactant, sodium vinyl sulfonate
as stabilizer, Sodium persulfate/metabissulfite as initiator, and
water. Surfactant, stabilizer, and initiator were investigated in
several different concentrations shown in Table 6. The initial
charges were fed at ambient temperature, and then the mixture was
maintained at 60.degree. C. followed by continuous feeds (6 hours
for vinyl acetate, 7 hours for initiator). After the additions, the
reaction was maintained at 60.degree. C. for additional 2 hours.
Samples were allowed to cold down to room temperature and then
analyzed by GPC, particle size, and GC or .sup.1H-NMR. Conditions
and Results are reported in Table 6.
6TABLE 6 Polymerization parameters Results Sodium Sodium Vinyl SDS
persulfate sulfonate Control (wt % to (wt % to (wt % to Conversion
Example agent monmer) monmer) monmer) (%) Mn PDI 64 Xanthate 1
0.366 0.2 100 16769 1.69 65 Xanthate 1.3 0.366 0.2 100 16727 1.64
66 Xanthate 1.6 0.366 0.2 100 16229 1.72 67 Xanthate 1 0.366 0.5
100 16050 1.71 68 Xanthate 1.3 0.366 0.5 100 15937 1.71 69 Xanthate
1.6 0.366 0.5 100 16606 1.75 70 Xanthate 1 0.407 0.2 100 17191 1.72
71 Xanthate 1.3 0.407 0.2 100 16288 1.62 72 Xanthate 1.6 0.407 0.2
100 16527 1.64 73 Xanthate 1 0.407 0.5 100 16729 1.71 74 Xanthate
1.3 0.407 0.5 100 16384 1.7 75 Xanthate 1.6 0.407 0.5 100 15524
1.72 76 Xanthate 1 0.4553 0.2 100 15855 1.73 77 Xanthate 1.3 0.4553
0.2 100 18588 1.67 78 Xanthate 1.6 0.4553 0.2 100 16761 1.75 79
Xanthate 1 0.4553 0.5 100 16844 1.69 80 Xanthate 1.3 0.4553 0.5 100
18441 1.73 81 Xanthate 1.6 0.4553 0.5 100 18357 1.64 82 Xanthate 1
0.5 0.2 100 18980 1.73 83 Xanthate 1.3 0.5 0.2 100 18427 1.71 84
Xanthate 1.6 0.5 0.2 100 17292 1.75 85 Xanthate 1 0.5 0.5 100 18500
1.7 86 Xanthate 1.3 0.5 0.5 100 19192 1.77 87 Xanthate 1.6 0.5 0.5
100 19389 1.8 88 CT-4 1 0.366 0.2 100 16464 1.48 89 CT-4 1.6 0.366
0.2 100 16135 1.47 90 CT-4 1 0.366 0.5 100 14794 1.45 91 CT-4 1.6
0.366 0.5 100 15245 1.46 92 CT-4 1 0.366 0.8 100 15877 1.46 93 CT-4
1.6 0.366 0.8 100 16345 1.48 94 CT-4 1 0.407 0.2 100 16721 1.49 95
CT-4 1.6 0.407 0.2 100 15780 1.46 96 CT-4 1 0.407 0.5 100 15425
1.46 97 CT-4 1.6 0.407 0.5 100 14902 1.44 98 CT-4 1 0.407 0.8 100
15427 1.45 99 CT-4 1.6 0.407 0.8 100 15963 1.43 100 CT-4 1 0.4553
0.2 100 16018 1.49 101 CT-4 1.6 0.4553 0.2 100 15216 1.51 102 CT-4
1 0.4553 0.5 100 15025 1.48 103 CT-4 1.6 0.4553 0.5 100 14183 1.54
104 CT-4 1 0.4553 0.8 100 14633 1.5 105 CT-4 1.6 0.4553 0.8 100
14927 1.55 106 CT-4 1 0.5 0.2 100 16291 1.57 107 CT-4 1.6 0.5 0.2
100 15785 1.54 108 CT-4 1 0.5 0.5 100 15849 1.58 109 CT-4 1.6 0.5
0.5 100 15923 1.6 110 CT-4 1 0.5 0.8 100 15697 1.59 111 CT-4 1.6
0.5 0.8 100 16283 1.57
[0118] It is to be understood that the above description is
intended to be illustrative and not restrictive. Many embodiments
will be apparent to those of skill in the art upon reading the
above description. The scope of the invention should, therefore, be
determined not with reference to the above description, but should
instead be determined with reference to the appended claims, along
with the full scope of equivalents to which such claims are
entitled. The disclosures of all articles and references, including
patent applications and publications, are incorporated herein by
reference for all purposes.
* * * * *
References