Living carbocationic polymerization. XXX. One-pot synthesis of allyl-terminated linear and tri-arm star polyisobutylenes,and epoxy- and hydroxy-telechelics therefrom

Mono- and di-ended linear and three-arm star allyl-telechelic polyisobutylenes, PIB? A, A? PIB? A and (where A = ? CH₂? CH?CH₂) have been prepared by a rapid economical one-pot polymerization-functionalization process. The process involves the living polymerization of isobutylene (IB) by mono-, di-, or tri-functional initiating systems, specifically by allphatic and aromatic tert-ester and -ether/TiCl₄ combinations, followed by electrophilic functionalization of the living sites with allyl-trimethylsilane (ATMS). Structural characterization by ¹H-NMR spectroscopy and end group titration with m-chloroperbenzoic acid (m-CPBA) indicate quantitative end allylation even with relatively slowly initiating systems like DiOAcTMH₇/TiCl₄. Detailed kinetic analysis of the latter system indicates, unexpetedly, cationation to be rate determining. Quantitative derivatizations of the allyl termini have yielded mono-, di-, and tri-epoxy- and -hydroxy-telechelic PIBs. Strong rubbery networks have been made by curing the epoxy-telechelic PIBs with triethylene tetramine and by reacting the hydroxy-telechelic PIBs with MDI.