Tensile and thermal properties of coconut shell powder filled polylactic acid biocomposites

Abstract

In this research the effect of coconut shell powder (CSP) content and chemical modification on mechanical properties, morphology and thermal properties of polylactic acid (PLA)/CSP biocomposites were studied. Coconut shell powder filled polylactic acid biocomposites was prepared using Brabender Plastrograph EC PLUS mixer at temperature 180oC and rotor speed 50 rpm. The results show that the increasing of CSP content has decreased the tensile strength and elongation at break but increased the modulus of elasticity of PLA/CSP biocomposites. The addition of CSP at 30 php has increased the glass transition temperature (Tg) and crystallinity (Xc) biocomposites. The decomposition temperature of maximum (Tdmax) of PLA/CSP biocomposites was raised with increasing of CSP content. The higher CSP content exhibited better thermal stability. The SEM study was proven that poor interfacial interaction between hydrophilic CSP and hydrophobic PLA. The different types of chemical modification such as acrylic acid (AA), maleic acid (MA) and 3-aminopropyl triethoylsilane (3-APE) were investigated. The treated biocomposites with AA, MA, and 3-APE have higher tensile strength and modulus of elasticity except elongation at break lower compared to untreated biocomposites. The chemical modification enhanced the Tg, Xc and thermal stability of treated biocomposites. The FTIR analysis show the chemical modification of CSP was reduced the hydroxyl group of CSP. The better interfacial interaction between CSP and PLA was proof by SEM study.