Concentration-Dependence of the Flory-Huggins Interaction Parameter of a Polymer Blend as Determined by Small-Angle X-Ray-Scattering Experiments

Abstract

Direct determination of the Flory-Huggins interaction parameter χ of a polymer blend by small-angle x-ray scattering experiments is possible on the basis of the random phase approximation, if absolute intensities are measured. The usually superposed void scattering has to be properly accounted for. Investigations on a series of blends of polystyrene and poly(styrene-co-bromostyrene) yielded χ dependent upon the blend composition. χ shows only slight variations. Scattering data also give the radii of gyration of the two components in the blend.