POLYMERS FROM MULTIFUNCTIONAL ISOCYANATES .12. ALTERNATING COPOLYMERSFROM ISOCYANATOALKENES AND ELECTRON-DEFICIENT 1,2-DISUBSTITUTED ALKENES

The free radical copolymerization of the electron rich monomers vinyl isocyanate, isopropenyl isocyanate, trans-1-propenyl isocyanate, and t rans-beta-styryl isocyanate with maleic anhydride has been investigate d. The copolymerization behaviour of different electron deficient mono mers like maleic anhydride, citraconic anhydride, N-phenylmaleimide an d fumaronitrile with isopropenyl isocyanate or vinyl isocyanate has al so been studied. Polymerization in benzene is accompanied by precipita tion of polymer, while the polymerization proceeds in solution in 2-bu tanone. Alternating copolymers were obtained in all cases. The alterna ting behaviour is favoured by the very low tendency of all monomers ex cept maleimides to undergo homopolymerization. From the reaction with maleic anhydride the reactivity of electron donating monomers was foun d to be vinyl isocyanate approximate to isopropenyl isocyanate much gr eater than beta-styryl isocyanate approximate to > 1-propenyl isocyana te, while the reactivity of electron accepting monomers with isopropen yl isocyanate was: maleic anydride > N-phenylmaleimide > fumaronitrile .