Nitroxide-Medaited Homopolymerization and Copolymerization of 2-Vinylpyridine with Styrene

摘要

Homopolymerization and copolymerization of 2-vinylpyridine (2VP) with styrene (8) at 125°C in the presence of2,2,6,6-tetramethyl piperidin-1:.yloxyl (TEMPO) radicals have been studied. The homopolymerization was carried out with 2,2'-azobis- (isobutyronitrile) (AIBN) as a thermal initiator or without AIBN in the initial reaction mixture. In the copolymerization initiated with AIBN, the molar fraction of 2VP in the feed, F 2VP, varied in the ra~ge of 0.1-0.9; F 2VP = 0.65 was found to be the azeotropic composition. The linear semilogarithmic time-conversion plots demonstrated a pseudo- living nature of the polymerizations under study. The molecular weight-conversion dependences indicated the participation of side reactions, diminishing the number of TEMPO-terminated polymer chains. The synthesized homopolymers and copolymers were characterized using size-exclusion chromatography (8EC), nitrogen analysis, and NMR spectroscopy.