A NOVEL SYNTHETIC ROUTE TO HIGHLY CROSS-LINKED POLY(VINYL ETHERS) .3.SYNTHESIS AND FREE-RADICAL POLYMERIZATION OF ARYLOXYETHYL VINYL ETHERS HAVING AN ELECTRON-ACCEPTOR IN ORTHO-POSITION OR META-POSITION

o-(2-vinyloxyethoxy)benzylidenemalononitrile (3a) and methyl o-(2-viny loxyethoxy)-benzylidenecyanoacetate (3b), m-(2-vinyloxyethoxy)benzylid enemalononitrile (4a), and methyl m-(2-vinyloxyethoxy)benzylidenecyano acetate (4b) were prepared by the condensation of o-(2-vinyloxyethoxy) benzaldehyde (1) and m-(2-vinyloxyethoxy)benzaldehyde (2) with malonon itrile or methyl cyanoacetate, respectively. Bifunctional vinyl ether monomers 3a and 3b polymerized quantitatively with radical initiators in gamma-butyrolactone solution at 65 degrees C, while meta-isomers 4a and 4b gave lower yields of polymers under the same conditions. The p olymers 5-6 obtained from the monomers 3-4 were insoluble in common so lvents due to cross-linking. Under the same polymerization conditions ethyl vinyl ether polymerized well with model compounds o-methoxybenzy lidenemalononitrile 7a, methyl o-methoxybenzylidenecyanoacetate 7b, m- methoxybenzylidenemalononitrile 8a, and methyl m-methoxybenzylidenecya no acetate 8b, respectively, to give 1:1 alternating copolymers 9-10 i n high yields. Cross-linked polymers 5-6 showed a thermal stability up to 300 degrees C, and showed a double phase degradation pattern in th eir TGA thermograms. Polymers 5-6 showed broad endothermic bands aroun d 75-110 degrees C without any characteristic T-g peaks in DSC thermog rams. Alternating copolymers 9-10, except copolymer 9b were soluble in common organic solvents. The inherent viscosities of polymer 9-10 wer e in the range of 0.35-0.62 dL/g. Polymer films cast from acetone solu tion were cloudy and tough and Tg values obtained from DSC thermograms were in the range of 118-165 degrees C.