Abstract

Homopolymerization of disubstituted styrenes (2,4- and 2,5-dimethylstyrene) and trisubstituted styrene (2,4,6-trimethylstyrene) and their copolymerization with styrene were carried out using diphenyl-zinc-metallocene-methylaluminoxane initiator systems for metallocene (n-BuCp) 2TiCl 2 and for half-metallocene CpTiCl 3. The studied comonomers were found to be less reactive than p-tertbutylstyrene, p-methylstyrene and styrene. The results indicate that, even though the methyl group has I+ inductive effect, di- and tri-methylstyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. © 2006 Society of Chemical Industry.