Abstract
New linear triblock copolymers consisting of a rubbery polyisobutylene (PIB) midsegment bonded both sides by glassy cyclized poly(1,3-pentadiene) (cy-PPD) blocks were synthesized by carbocationic polymerization using sequential monomer addition. First, the living polymerization of isobutylene (IB) was induced by bifunctional dicumylmethylether (DiCumOMe)/TiCl 4 as initiating system in n-hexane/CH 2Cl 2 (1/1 v/v) as solvent mixture at −60°C in the presence of DMSO as electron donor (ED). After the living PIB sequences had reached the desired number average molar weight ( M n) in the range of 5000 to 25 000 g mol −1, 1,3-pentadiene (PD) was added to produce the hard cy-PPD outer blocks with M n close to 6000 g mol −1. The crude copolymers were purified by CH 2Cl 2 extraction at −60°C and characterized by size exclusion chromatography (s.e.c.) and nuclear magnetic resonance (n.m.r.) spectroscopy.
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