Cationic Polymerization of Cyclic Ethers Initiated by Macromolecular Dioxolenium Perchlorate

Abstract

Cationic polymerization of tetrahydrofuran (THF) with 2-methyl-1,3-dioxoleum perchlorate proceeded as a living system without chain transfer and termination, and the initiation reaction was shown to be the bonding mechanism. Poly-THF with terminal dioxolenium perchlorate group was synthesized from poly(tetramethylene glycol) by stepwise reaction with adipoyl chloride, ethylene bromohydrin, and silver perchlorate. The quantitative formation of macromolecular dioxolenium salt was proved from the polymerization behavior of the THF. Polymerization of 3,3-bischloromethyloxetane by the initiator yielded block copolymer, and no chain-transfer reaction except the termination reaction was observed. Polymerization of 7-oxabicyclo[2.2.1]-heptane by the initiator yielded homopolymer as well as block copolymer, and a significant amount of chain transfer reaction was observed. Polymerizatian of dioxolane and tetraoxane by the initiator yielded little block copolymer, demonstrating the different mechanism of the initiation reaction in the case of cyclic formals.