Molecular design of diene monomers containing an ester functional group for the synthesis of poly(diene sulfone)s by radical alternating copolymerization with sulfur dioxide

Abstract

Functional poly(diene sulfone)s are prepared by the radical alternating copolymerization of 1,3-diene monomers containing an ester substituent with sulfur dioxide. Methyl 3,5-hexadienoate (MH) and methyl 5,7-octadienoate (MO) with both an alkylene spacer and a terminal diene structure are suitable to produce a high-molecular-weight copolymer in a high yield, while the copolymerization of 5,7-nonadienoic acid, ethyl 2,4-pentadienoate, and ethyl 4-methyl-2,4-pentadienoate including either an alkylene spacer or a terminal diene structure lead to unsuccessful results. The 13C NMR chemical shift values of MH and MO suggest a high electron density at their reacting α-carbon for exhibiting a high copolymerization reactivity. Fluorene-containing diene monomers, 9-fluorenyl 3,5-hexadienoate (FH) and 9-fluorenyl 5,7-octadienoate (FO), are also prepared and copolymerized with sulfur dioxide. The thermal and optical properties of the poly(diene sulfone)s containing the methyl and fluorenyl ester substituents in the side chain are investigated.