Effect of chemical treatment via maleic anhydride on the properties of high-density polyethylene/prickly pear powder composites: Experimental investigation and ANOVA-based statistical analysis

This study investigates the effects of particle size, filler concentration, and maleic anhydride (MA) treatment on the properties of high-density polyethylene (HDPE)/prickly pear powder (PPP) composites. Untreated PPP (UPPP) and MA-treated PPP (TPPP) were incorporated into the HDPE matrix at filler contents of 10, 20, and 30 wt% using two-roll mixing followed by compression molding. The resulting composites were characterized through FTIR, MFI, tensile, hardness, water-absorption, and optical microscopy analyses. FTIR results confirmed successful surface modification of PPP by MA, evidenced by reduced hydroxyl-group intensity and enhanced ester carbonyl absorption, indicating improved filler–matrix compatibility. Increasing filler content reduced MFI values, particularly for TPPP composites, due to restricted polymer-chain mobility and stronger interfacial interactions. Mechanical characterization showed that MA treatment significantly enhanced composite performance. Compared with neat HDPE, TPPP composites exhibited increases of approximately 77.8% in tensile strength and 38.7% in Young’s modulus, together with higher hardness and improved impact resistance relative to untreated composites. Water absorption was markedly reduced after MA treatment owing to decreased filler hydrophilicity and improved interfacial adhesion. Optical microscopy revealed more uniform filler dispersion and fewer interfacial defects in TPPP composites. TPPP proved to be an effective and sustainable reinforcement for producing lightweight, high-performance HDPE composites.