STYRENE POLYMERIZATION WITH SOME NEW MACRO OR MACROMONOMERIC AZOINITIATORS HAVING PEG UNITS

Several new macroinitiators and macromerinitiators (macroinimers) were synthesized and evaluated for the bulk polymerization of styrene at 6 0-degrees-C. Macroinitiators were prepared from the reaction of 4,4'-d icyano-4,4' azovaleryl chloride (1) with poly(ethylene glycol) (PEG) w ith a M(w) of 400 and with either benzoyl chloride, acetyl chloride, p henyl isocyanate, or poly(ethylene glycol) oleyl ether. Macromer initi ators were also prepared from the reaction of 1 with PEG having M. val ues of 200,400,600, 1000, or 1500 and with 4-vinylbenzyl chloride. The bulk polymerization of styrene by macroinimers gave crosslinked styre ne-PEG block copolymers, while the polymerization by macroinitiators g ave soluble copolymers. The molecular weights of the styrene-PEG block copolymers obtained with macroinitiators having either oleyl, benzoyl , or phenyl urethane end groups were 22000-29000 g/mol. DSC measuremen ts showed that the crosslinked block copolymers had crystalline PEG un its with melting transitions ranging from 11-37-degrees-C. (C) 1994 Jo hn Wiley & Sons, Inc.