Degradation of high polymers in pipes with particular reference to the manufacture of synthetic fibres

Abstract

AbstractA model is developed for the degradation of fibre‐forming high polymers. Overall degradation is divided into three types of degradation: (i) thermal degradation based on the mean residence time; (ii) thermal degradation in the boundary layers caused by a prolonged residence time at the walls; (iii) degradation induced by mechanical effects (this type of degradation occurs, in particular, at low temperatures, i.e. at high dynamic viscosities, since it is proportional to the shear stress). In an example, the degradation in a pipe is reduced to a minimum. It is stated that an optimum value can always be fixed for the tube diameter and the operating temperature.