Initiation of cationic polymerization with alcohol/Lewis acid systems

Summary

The discovery that tertiary alcohols in conjunction with BCl₃ are efficient cationic polymerization systems was exploited for the synthesis of new graft and block copolymer, i.e., poly (styrene-g-isobutylene), poly (isobutylene-g-indene) and poly (isobutylene-b-indene). Syntheses involved the initiation of isobutylene and indene polymerizations by polymeric alcohols (i.e., randomly hydroxylated polystyrene, and randomly terminally hydroxylated polyisobutylene) in the presence of BCl₃. The starting prepolymers, i.e., hydroxylated polystyrene and polyisobutylene, were synthesized by conventional techniques. The syntheses of these sequential copolymers prove that the mechanism proposed for initiation with ROH/BCl₃ systems is fundamentally correct.