Spinning of Fibers from Graft Copolymers of Polyacrylonitrile and Poly(Methyl Acrylate)
Fibers were spun from graft copolymers of polyacrylonitrile and poly(methyl acrylate). Increasing poly(methyl acrylate) side chains from 5 to 8% decreased the viscosity of the spinning solution in dimethylformamide. The spinning solutions were unstable. When the graft copolymer contained 5% side chains, the viscosity of these solutions returned to almost its initial value by heating. Fibers were obtained from graft copolymers containing from 5–13% poly(methyl acrylate) side chains. These were formed at the temperature of the coagulation bath (50°C), while at temperatures less than 50°C the fibers were not obtained. Weak fibers were produced from a graft copolymer containing 13% side chains at the temperatures of the coagulation bath (20 and 50°C). No fibers were obtained from graft copolymer containing 25% side chains. The method of dissolution of the graft copolymers does affect the drawing of fibers produced from them. It was observed that the heating of the spinning solution decreases the amount of drawing of the produced fibers. The presence of the flexible side chains of poly(methyl acrylate) in the graft copolymer improves the maximum possible degree of drawing of the fibers relative to that of fibers from the initial linear copolymer and homopolyacrylonitrile.