Living Carbocationic Polymerization. Li. Living Carbocationic Copolymerization of Indene and<i>p</i>-Methylstyrene. 1. Demonstration of the Living and Random Copolymerization of Indene and<i>p</i>-Methylstyrene

Abstract

Abstract The living carbocationic polymerization and copolymerization of indene (Ind) and p-methylstyrene (pMeSt) have been investigated by the use of the 2-chloro-2,4,4-trimethylpentane (TMPCl)/TiCl4 and the 2-chloro-2-propylbenzene (cumyl chloride, CumCl)/BCl3 initiating systems in the presence of triethylamine (Et3N) as electron donor and CH3Cl or CH3Cl/QH14 mixed solvents at −80°C. The TMPCl/TiCl4 initiating system gives essentially living copolymerization with slow initiation up to M n ≈ 20,000. The CumCl/BCl3 initiating system also induces living Ind homopolymerization up to at least M n ≈ 13,000. The homopolymerization of pMeSt with the latter initiating system, however, is not living as it shows evidence for a large amount of chain transfer. Thus, with the CumCl/BCl3 combination a small amount of chain transfer has apparently been observed in the presence of 50% of pMeSt in the charge. Reactivity ratio studies, fractionation, 1H- and 13C-NMR spectroscopy, and glass transition temperature (Tg ) investigations indicate that virtually random Ind-co-pMeSt copolymers of M n ≈ 20,000 can be obtained under suitable conditions. The Tg of the copolymers can be controlled between ≈115°C (the Tg of PpMeSt) and ≈194°C (the Tg of PInd) by the relative composition of the two monomers in the charge.