Halogen-free polyisobutylene by in situ methylation of living polyisobutylene using dimethylzinc

摘要

Halogen-free polyisobutylene (PIB) was synthesized by in situ methylation of living PIB using dimethylzinc. Quantitative methylation of lving PIB was achieved within 60 min using a ratio of [(CH_3)_2Zn]/[TiCl_4]_0 = 1 without any side reactions. Under similar conditions, living PIB capped with 1,1-diphenylethylene (PIB-DPE~+) yielded close to 1:1 mixture of methoxy-and methyl-functionality. By using the ratio of [(CH_3)_2Zn]/[TiCl_4]_0 >=3, however, quantitative methylation of PIB-DPE~+ could be achieved in 120 min without any side reactions as confirmed by spectroscopic and chromatographic analyses.