Effect of nanosilica and aluminum hydroxide on thermal, flammability, and morphology properties of nanocomposite made of recycled high-density polyethylene and OCC flour

Effects of nanosilica and aluminum hydroxide were considered relative to thermal, flammability, and morphological properties of nanocomposites from recycled high-density polyethylene (rHDPE) and old corrugated container (OCC) pulp. Amounts of 50% recycled high-density polyethylene and 50% OCC flour were used. The nanosilica was used at three weight levels of 0%, 5%, and 10%. Lastly, aluminum hydroxide at a constant level of 5% and maleic anhydride grafted polyethylene at a constant level of 3% were mixed by twin screw extruders. The samples were made using a hand-press. The thermal and flammability properties were then measured. To consider the structure and function of nanosilica, the morphological characteristics of wood-plastic composites (WPC) were studied by X-ray diffractograms (XRD) and scanning electron microscopy (SEM) analyses. The results showed that increasing the nanosilica content up to 10% increased the thermal stability, and more charcoal was retained. Moreover, the limited oxygen index increased. X-ray diffractograms showed that the width and peak intensity decreased with the increased intake of silica nanoparticles. The SEM images showed that more adaptability was achieved through increasing the amount of nanosilica. Additionally, better and more homogenous bonds were observed between the fibers and connection matrix, and fewer gaps and pores were observed.