Effect of Coupling Agent on Properties of Composites Made from Styrofoam Waste and Coconut Shell

Abstract

Styrofoam is amongst one of the highly used packaging materials due to its lightweight and vibration isolate properties. The usage of styrofoam rises yearly, but it is seldom received by the recycling facilities to recycle the post-consumed styrofoam due to the poor economic viability. The objective of this research is to investigate the potential value of recycling post-consumed styrofoam as feedstock in producing sustainable composite materials. Therefore, this study would increase the feasibility and interest in recycling of styrofoam and indirectly continue the life cycle of styrofoam waste. In this study, the composites with varying compositions were of recycled polystyrene (rPS), coconut shell (CS) and maleated polystyrene (MAPS) compounded using an internal mixer. The effects of compositions on torque rheological, flexural and morphological properties of the composites were investigated. The findings showed that rPS/CS composites filled with more CS content possesses higher processing torque due to increase in viscosity. However, addition of MAPS lowered the viscosity of composites. The flexural properties revealed that the rPS/CS composites without MAPS exhibited the highest flexural strength and modulus of 33.5 MPa and 3.1 GPa, respectively, when the CS content was measured at 30 wt%. Then, the addition of MAPS improved on average 29% of flexural strength and 14% of flexural modulus, individually. The results from scanning electron microscopy showed that the addition of MAPS had improved the interfacial adhesion between rPS matrix and CS particles, which resulted in an improvement on flexural properties. The flexural properties of rPS/CS composites are comparable to wood plastic composites (WPC) as found in literature, which demonstrates its potential to be used in applications similar to WPC.