Compatibilization of Metallocene Polyethylene/Polyamide Blends with Maleic Anhydride Studied by Positron Annihilation

Abstract

Positron lifetime spectroscopy was used to study the compatibilization effect of maleic-anhydride (maH) grafted copolymers and its ionomers in metallocene polyethylene/poly-amide blends. The ortho-positronium (o-Ps) lifetime τ3 showed a decrease with increasing maH content from 0 to 0.5%, then remained constant. A larger decrease was observed for the Na+-neutralized ionomer containing blends. From the analysis of continuous positron lifetime distribution, we found that in the blend with no or smaller maH content, the o-Ps lifetime distribution was composed of two peaks, which can be attributed to the phase separation in these blends. When the maH content was equal to or higher than 0.5%, the phase separation disappeared, which is due to the decrease of dispersed polyethylene (PE) phase size. In the blends with ionomer, the phase separation disappeared at a lower content of maH. These results proved that the maH grafted copolymer and ionomer can be very good compatibilizers for the PE/PA blends.