Sustainable Materials: Value-Added Composites from Recycled Polypropylene and Fly Ash Using a Green Coupling Agent

Composites were developed from two industrial wastes: recycled polypropylene (R) and fly ash (FA). Surface coating of fly ash (FA) particles with palmitic acid (PA) in different wt % of 1, 2, 3, and 5 were done, and they were incorporated as filler in the R matrix by melt mixing. X-ray diffraction analysis (XRD), mechanical characterization, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and fracture surface analysis were carried out with a scanning electron microscope (SEM) to establish, structure-property correlation. Crystallinity changed significantly, resulting in improved properties in 1 wt % PA-coated FA/R (RFAPA1) and 2 wt % PA-coated FA/R (RFAPA2) composites. Impact strength increased by 132% in RFAPA1, and an increase in glass transition temperature was observed in RFAPA1 and RFAPA2. RFAPA1 and RFAPA2 exhibited enhanced thermal stability, and SEM revealed improved interfacial compatibility. These results showed the possibility of using a renewable green chemical like PA as a coupling agent in place of conventional expensive silane coupling agents to develop sustainable value-added polymer composites from environmentally hazardous waste materials.