A novel synthetic route to highly cross-linked poly(alkylvinylether)s

Abstract

p-(2-Vinyloxyethoxy)benzylidenemalononitrile (3) and methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate (4) was prepared by the condensation of p-(2-vinyloxyethoxy)benzaldehyde with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 3 and 4 polymerized quantitatively with radical initiators in γ-butyrolactone solution at 65°C. The trisubstituted terminal double bond participated in the vinyl polymerization and radical polymerization of 3 and 4 led to swelling polymers 5 and 6 that were not soluble in common solvents due to cross-linking. Under the same polymerization conditions ethyl vinyl ether polymerized well with model compounds of p-methoxybenzylidenemalononitrile and methyl p-methoxybenzylidenecyanoacetate, respectively, to give 1:1 alternating copolymers 9 and 10 in high yields. Alternating copolymers 9 and 10 were soluble in common solvents such as acetone and DMSO, and the inherent viscosities of the polymers were in the range of 0.36–0.74 dL/g. Films cast from acetone solution were cloudy and tough and Tg values obtained from DSC thermograms were in the range of 59–60°C.