Order in Main Chain Thermotropic Random Copolymers

Abstract Model calculations are presented which account for some of the main features of fibre diffraction patterns of main chain thermotropic random copolymers. It is shown that non- periodic layer (NPL) crystallites are consistent with these features, in particular the relative concentrations of the 1st, 2nd and 3rd layer lines onto the meridian, provided that a small degree of randomness is allowed in the longitudinal register between the chains. A partially ordered fringe area, which surrounds each NPL crystallite, is shown to retain some degree of register.