| Title: FREE RADICAL COPPER (II)-ENOLATE POLYMERIZATION INITIATORS Inventor(s):
H. J. Harwood, S. Goodrich
Disclosure 198(a) U.S. Patent 5,405,913
Disclosure 198(a)-DIV U.S. Patent 5,470,928
The invention describes a redox initiating system consisting of CuII salts, enolizable
aldehydes and ketones, and various combinations of coordinating agents for CuII,
coordinating agents for CuI, and a strong amine base that is not oxidized by CuII. In
particular, CuII octanoate / dibenzyl ketone / pyridine / triethylamine /
triphenylphosphine systems are effective.
The advantages of this technology are (1) Cu(II) is a mild, selective oxidizing agent
that is tolerant of numerous monomer functional groups; (2) the coreactants are also mild
and the system in general is insensitive to moisture; (3) the use of triphenylphosphine as
a coreactant exploits the ability of Cu(I) to form a stable complex with the phospine to
drive the reaction, which is crucial especially in blocking reactions in which the
concentration of chain-ends is very low; (4) block and graft copolymers essentially free
of homopolymer can be prepared by using this initiation chemistry.
This invention solves problems associated with (1) synthesis of polymers with a
predictable end-group structure that can bear a useful functional group; (2) synthesis of
block and graft copolymers essentially free of homopolymers, which is the exception rather
than the rule in free radical polymerization; and (3) synthesis of solvent-resistant
thermoplastic elastomers with the potential for high Tg or Tm step-growth hardblocks.
This technology is ideally suitable for (1) initiation of free radical polymerizations
and copolymerizations in solution, bulk, suspension and emulsion; (2) synthesis of
functionalized telechelics; (3) synthesis of polymers with ketone backbone linkages; (4)
synthesis of block and graft copolymers involving free radical and step-growth polymer
blocks or based on other aldehyde- or ketone-functional prepolymers; (5) synthesis of
thermoplastic elastomers that are solvent resistant, with the potential of having high Tg
or Tm step-growth hardblocks; and (6) crosslinking reactions. |
