Examination of the surface microstructure of α-alumina filled HDPE nanocomposites using positron annihilation methods

High-density polyethylene (HDPE) nanocomposites with alpha alumina nanoparticles at various weight fractions (0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, and 3 wt%) were successfully synthesized using the hot press method. X-ray diffraction (XRD) results revealed that increasing the weight percentage of alumina had no significant effect on the initial semi-crystallinity. Atomic force microscopy (AFM) images revealed that achieving high surface homogeneity is possible at higher alumina contents. Positron annihilation lifetime spectroscopy (PALS) and low energy positron beam technique (LEPB) were used to investigate the size, concentration and shape of the free volume. The results from positron annihilation spectroscopes indicated that increasing the weight percentage of alumina reduces the size, shape, and homogeneity of free volume structure.