The Influence of Acrylic Acid Groups on the Microstructure of HDPE/PS/clay System Studied by Positron Annihilation

摘要

Two types of composites-an immiscible blend, high density polyethylene/ polystyrene (HDPE/PS) with clay, and a compatibilized blend, high density polyethylene grafted with acrylic acid/PS (PEAA/PS) with clay-were prepared via melt compounding. X-ray diffraction (XRD) results revealed that the dispersion of clay in compatibilized blends was better than immiscible blends. Positron annihilation lifetime spectroscopy (PALS) has been utilized to investigate the microstructure of two types of composites. The ortho-positronium (o-Ps) intensity for PEAA/PS was lower than that for HDPE/PS. With the increase of clay content, the o-Ps intensity increased for PEAA/PS/clay composites and the o-Ps intensity decreased for HDPE/PS/clay composites. It was found that the carboxyl group of Acrylic acid played a significant chemical inhibition on positronium formation. The results provided an evidence for that the chain segments with carboxyl group would be easier to intercalate the gallery of silicates.