Mechanical Properties of waste plastic composites reinforced with untreated and alkali treated Coconut Shell Powder as filler

Abstract

This study investigated the mechanical properties of a polymer matrix composite from waste plastic (sachet water pouches, SWP) reinforced with untreated and alkali treated coconut shell powder (CSP). The NaOH concentrations were 4, 6 and 8 % wt. /v; treatment time was 120 minutes and temperature was 70°C. The composites were fabricated using compression moulding technique and subjected to mechanical testing. The alkali treated SWP/CSP composites showed an increase in tensile strength and modulus of 19.18% and 20.65% respectively, relative to the untreated composites. Flexural strength and modulus improved by 39.15% and 69.13% respectively, while the impact strength increased by 40.05% when compared with the untreated counterparts. These improvements were attributed to better compatibility between the SWP matrix and alkali treated CSP filler, confirming the effectiveness of alkali treatment of lignocellulosics in the production of polymer matrix composites. On the other hand, elongation at break was observed to have decreased by 19.84% compared to composites made from untreated CSP. The untreated SWP/CSP composites recorded poor tensile and flexural properties in contrast to those from treated CSP due to poor interfacial bonding between the polymer matric and untreated CSP. Overall, the study demonstrated that the use of CSP in polymer composites is a sustainable and an environmentally friendly approach to waste management.