Thermal, structural and morphological properties of High Density Polyethylene matrix composites reinforced with submicron agro silica particles and Titania particles

HDPE-based composites samples filled with 2, 4, 6, 8 and 10 wt.% submicron agro-waste silica particles extracted from rice husk ash (RHA) at constant 0.3 wt.% Titania loading were prepared using rapra single screw extruder at temperature of 200-230 °C. The extrudates were compressed with a laboratory carver press at a temperature of 230 °C for 10 min under applied pressure of 0.2 kPa and water cooled at 20 °C min−1. Thermal, structural and morphological properties of the composites were studied. The results of the thermogravimetric analysis (TGA) revealed that the composites with 10 wt.% SiO2 have the best maximum thermal degradation temperature of 438.73 °C. The crystal structure of neat HDPE, and the siliceous composites developed revealed two obvious diffractive peaks of about 21.3° and 23.7° corresponding to typical crystal plane (1 1 0) and (2 0 0) of orthorhombic phase respectively. The diffractive peaks do not shift with the addition of silica particles; this clearly indicates that the addition of silica particles did not exert much effect on the crystalline structure of HDPE. There is no much difference in the interplanar distance (d-value). Lamellar thickness (L) of HDPE increases with the addition of silica particles, which implies that silica particles aid the formation of more perfect crystals. Scanning electron microscopy studies indicated that there were chains inter diffusion and entanglement between HDPE matrix and the silica particles at lower weight fraction (2-4 wt.%) of submicron silica particles which resulted into homogeneous dispersion of the particles within the matrix.