Single phase polystyrene - polyacrylonitrile- dimethylformamide system studied by light scattering

The single phase system consisting of polystyrene and polyacrylonitrile in a mass ratio of 3∶1 and dimethylformamide as a low-molecular weight solvent was studied by the light scattering method. The dependence of the ratio between the experimentally found and calculated intensities of scattered light on the scattering angle, θ, and on the total polymer concentration was followed. It was established that the concentration of the beginning of association of macromolecules could be determined by light scattering at various angles. The method of dissymmetry and the Zimm method were applied for determination of the root-mean-square dimensions of coils, weight-average molecular weight, second virial coefficient and specific volume of macromolecules. The values of macromolecular parameters of the system studied were compared with the corresponding values of the individual polymer solutions. On the basis of the data obtained, it was shown that in the mixed solution occur contraction and association of the macromolecules.