Abstract: A suitable precursor for the production of carbon fibre is an acrylonitrile copolymer containing at least one non-acrylic moiety which is a carbonyl group a hydroxymethylene group, --CH(OH)-- or a two carbon moiety containing a carbonyl group or a hydroxymethylene group and in which the non-acrylonitrile moiety is present to the extent of 5 to 15 molar parts per 100 molar parts of acrylonitrile moiety.The preparation of such copolymers and their conversion to carbon fibre is described.

Abstract: A process for the production of carbon fibres is described in which a precursor fibre which is a copolymer of acrylonitrile, a chlorinated monomer, and itaconic acid containing between 2 to 20 molar parts of chlorinated comoner, between 0.5 and 5 molar parts of itaconic acid and 0 to 5 molar parts of other comonomers per 100 molar parts of acrylonitrile to a temperature in the range 200.degree.-400.degree. C while the natural shrinkage of the fibre is at least restrained followed by further heat treatment at a temperature in the range 800.degree.-3000.degree. C in a non-oxidizing atmosphere.