Understanding the properties and flow characteristics of recycled polyolefins in rice hull composite blends is of importance to facilitate process optimization whilst promoting sustainability. The influence of milled rice hull particle size (<0.5 mm and <1 mm) on properties of recycled polyolefins composites was studied with major focus on recycled high-density polyethylene (rHDPE) and polypropylene (rPP) together with added maleated polymer coupling agents. Composites were compounded/extruded using a twin-screw extruder and the thermal, mechanical, and physical properties were analyzed as well as their melt flow, dynamic. and capillary rheology tests. The incorporation of the <0.5 mm rice-hulls particles enhanced the composite properties of viscosity, flexural strength, moduli, water absorption, and thermal stability for both polyolefins with rHDPE composites showing more reliable properties as compared to rPP.
Keywords: polyolefins; recycled high-density polyethylene; recycled polypropylene; rheology; rice hulls.