Pyrolysis of polyacrylonitrile and related polymers—IX: Copolymers of acrylonitrile with vinyl chloride,vinylidene chloride and α-chloroacrylonitrile

In the pyrolysis of copolymers of acrylonitrile with chlorinated comonomers, dehydrochlorination occurs readily and precedes the exothermic oligomerization of the nitrile groups. The comonomer units reduce the intensity of the exotherm reaction but do not effectively block the reaction since it is clear that the oligomerization of nitrile groups remains extensive. Vinylidene chloride and α-chloroacrylonitrile copolymers exhibit excellent thermogravimetric characteristics; it is concluded that crosslinking through the comonomer unit reduces the amount of fragmentation and hence of weight loss from the polymer. The favourable thermoanalytical behaviour suggests that acrylic compositions of this type could be used for carbon fibre processing.