INITIATION VIA HALOBORATION IN LIVING CATIONIC POLYMERIZATION .2. KINETIC AND MECHANISTIC STUDIES OF ISOBUTYLENE POLYMERIZATION

We have discovered that in the presence of a proton trap to trap proti c impurities, BCl3 alone can initiate the polymerization of isobutylen e, leading to low molecular weight asymmetric telechelic polyisobutyle nes carrying a BCl2 head group and a tertiary chloro end group. Two po lymerization schemes are proposed to explain the results, one based on initiation by self-dissociation of BCl3 and another involving halobor ation-initiation. Kinetic and mechanistic studies support the proposed new initiation mechanism via haloboration and explain the apparent li vingness of the polymerization.