Structuring in solutions of blends of a polyamido acid with polyacrylonitrile and the properties of the films based on them

Scattering of polarized light has been employed to investigate the structure of solutions of poly(4,4′-oxydiphenylene)pyromellitamido acid (PAA), linear PAN and modified PAN (PAN-1) and also their blends with a different content of the starting components in the concentration range 1–13%. In solutions of PAN-1 and its blends with PAA as compared with solutions of only PAA there is higher structural orderliness; PAN-1 and its blends with PAA in solution display a tendency towards crystallization. The polymer-polymer interaction PAA-PAN-1 in the solutions of the blends is confirmed. In a 13% solution of the mixture of PAA with PAN-1 (80:20) association processes were found developing in time to reach a maximum within 7–8 days. Combination of the considerable dimensions of the associates of the macromolecules peculiar to PAA solutions and the high microanisotropy appearing in the presence of PAN-1 ensures good deformation-strength properties of the composite materials based on blends of composition PAA:PAN-1 = 80:20 (% by weight).