Studies on the physico‐mechanical,thermal, and morphological behaviors of high density polyethylene/coleus spent green composites

This study is aimed at utilizing nutraceutical industrial waste and reducing carbon footprints of plastics. Eco‐friendly “green composites” of high density polyethylene (HDPE) were fabricated using coleus spent (CS)—a nutraceutical industrial waste as reinforcing filler and maleic anhydride‐graft‐polyethylene (MA‐g‐PE) as compatibilizer. Composites were fabricated with 5, 10, 15, and 20% (w/w) of CS by extrusion method. The fabricated HDPE/CS composites were evaluated for mechanical and thermal behavior. A slight improvement of about 5% in tensile strength and marked improvement of about 25% in tensile modulus for 20 wt % CS filled HDPE composites was noticed. The effect of CS content on rheological behavior was also studied. Thermal characteristics were performed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA thermogram indicated increased thermal stability of CS‐filled composites. From TGA curves the thermal degradation kinetic parameters of the composites have been calculated using Broido's method. The enthalpy of melting (ΔH_m) obtained from DSC curves was reduced with increase in CS content in HDPE matrix, due to decrease in HDPE content in composite systems. An increase in CS loading increased the water absorption behavior of the composites slightly. Morphological behavior of cryo‐fractured composites has been studied using scanning electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011