Improvement of Mechanical and Flame Retardant Properties of Natural Rubber by Eco-friendly Watermelon Peel and Crumb Rubber

This work aimed to investigate the suitability of using watermelon peels powder (WPP) and crumb rubber (CR) as alternatives to fillers flame retardant chemicals to reduce cost. The new composites of natural rubber (NR) and watermelon peels powder (0, 5, 10 phr) were produced by mixing them in the presence of crumb rubber powder loaded (0, 5, 10 phr). The structure of the composites was characterized by X-ray diffraction (XRD). Both scanning electron microscope (SEM) and energy dispersive X-ray (EDX) were used to investigate the morphology of the NR composites. The mechanical properties, such as tensile strength (TS) and elongation (E%) were measured. The contact angles of deionized water (DIW) and glycerol (GL) drops on the NR composite surface were measured. The combustion analysis of the NR composites was tested using differential thermal analysis (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and flame chamber (UL-94) according to standards. The results indicated the effect of the WPP in mechanical properties and combustion analysis for the NR composites when blended with different weight % of CR.