AbstractThis article aims to carry out mathematical modeling of the mechanochemical degradation process of acrylonitrile–α‐methyl styrene–vinyl acetate ternary copolymer in conditions that simulate its wet‐spinning from dimethyl formamide solution. The influence of some factors on the mechanochemical degradation process is studied. Based on a great number of experiments a regression equation is determined, which correlates the intrinsic viscosity of the copolymer solution with the mechanical process variables (the length and length/diameter ratio, solution concentration, and pressure).