Mixed Agro-waste Biocomposites of Low Density Polyethene; Impact of Fillers on Mechanical, Morphological, Water Imbibition and Biodegradability Properties

Abstract

In retrospect, the incorporation of agricultural waste as a natural, biodegradable filler in polymer composites is a scientific innovation that has received global attention. This is due to its impact in enhancing sustainability of composites and degradation of plastics. The mechanical, morphological, water imbibition and biodegradability properties of low density polyethene produced composites were investigated using agro wastes blend of corn cobs and sugarcane bagasse. Agro waste with a particle size of 75µm was blended in a 50:50 ratio and integrated into LDPE polymer matrix at different percentages of 0%, 5%, 10%, 15%, and 20%, with composites fabricated via injection molding. The mechanical properties like the tensile strength, percentage elongation at break, compressive strength, shear modulus and hardness test of the composites were studied in line with ASTM standards. Also, the morphological properties were studied with a Scanning Electron Microscope. From the results, there was a reduction in tensile strength of the composites with increasing filler loading. However, the percentage elongation at break of the LDPE composite increased as the filler loading increased as an indication that the composite is relatively ductile. Hardness, compressive strength and shear modulus of the polymer composites increased with increasing filler loading. Morphological study of the composites showed a good adhesion and interfacial bonding between the filler and the polymer matrix due to good dispersion of the fillers in the polymer matrix. Biodegradation test revealed a reduction in the mass of the composites after a 3- month burial period which was more pronounced after a 30-day test period indicating that the composite is more environmentally friendly. The highest degradation rate was observed at 20wt% CCSB-LDPE composite giving a 15% reduction after 90days. Result from the water imbibition test indicated no increase in the mass of the composites after immersion in water. This is an indication that the composite can be utilized in wet environments. Hence, from the findings, it is suggested that agro-wastes like rice husk and sugarcane bagasse be employed as fillers in the manufacture of plastics because they are cheaper and viable. Finally, the produced plastics would degrade when discarded