Potential utilization of rubberwood flour and sludge waste from natural rubber manufacturing process as reinforcement in plastic composites

The present study aims to evaluate and compare the potential of rubberwood flour (RWF) and sludge waste from manufacturing process of the concentrated natural rubber latex as reinforcement in recycled high-density polyethylene (rHDPE) composites. Morphological, thermal, mechanical and physical properties were investigated. The results indicated that the tensile modulus (TM), modulus of elasticity (MOE) and hardness of rHDPE composites containing sludge waste flour (SWF) were improved with the increasing amount of SWF; however, the tensile strength (TS), modulus of rupture (MOR) and water absorption (WA) exhibited a negative correlation with the SWF concentration. The composites based on SWF exhibited better TS, MOR, maximum flexural strain and WA than that of based on RWF. The thermal experiments showed that the decomposition temperatures of the rHDPE composites with SWF were higher than that of with RWF. Further, the addition of maleic anhydride-grafted polyethylene improved the mechanical and physical properties of the composites reinforcing the SWF or RWF. The above results showed that the utilization of latex sludge waste could become a promising way for solving the environmental problem as well as improving many properties of plastic composites.