This technology is available from Temarex Corporation.
REDOX INITIATING SYSTEM
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.