POSITRON LIFETIMES IN BLENDS OF RECYCLED POLYSTYRENE AND POLYETHYLENE

Positron lifetimes and intensities are used to characterize the microstructure of products made from the blending of recycled plastics: post-industrial polystyrene and post-consumer high density polyethylene. For samples of various compositions, the extent of polymeric microheterogeneity (homogeneity) is estimated, the degree of crystallinity of the polyethylene phase, and, using a trapping model, the size and number of microvoids. The results obtained correlate well with wide-angle x-ray diffraction measurements and mechanical properties. A unique morphology which results in optimal properties is identified using positron annihilation.