The Effects of Different Chemical Treatment Methods and Maleic Anhydride Grafted Polyethylene on the Mechanical and Thermal Properties of <i>Alpinia galanga</i> Fiber Reinforced Polyethylene Composites

In this study, the effect of different treatments and the addition of maleic anhydride grafted polyethylene (MAPE) on the mechanical and thermal properties of Alpinia galanga (AG) fiber/high-density polyethylene (HDPE) composites were investigated. The AG fibers were pretreated with sodium hydroxide (NaOH) and then treated with 3-aminopropyltriethoxysilane (3-APE) as well as treated with p-toluenesulfonic acid (PTSA). The samples were first prepared by melt blending method before being injected to specimen dumbbell shape using an injection moulding machine. Three different fiber loadings were studied, such as 3, 6, 10 and 15 wt%. The tensile test results revealed that the NaOH and 3-APE treatments increased the tensile strength of AG/HDPE composites with the addition of MAPE at all fiber loadings, whereas tensile strength of PTSA treatment improved at 3 wt% fiber loading. The morphological studies confirmed a better adhesion between treated fiber and HDPE matrix with the inclusion of MAPE. Thermal analysis study showed that NaOH, 3-APE and PTSA treatments on AG fibers improved the thermal stability of the composites with an addition of MAPE by delaying the thermal degradation of the composites. The water absorption test proved NaOH and 3-APE treated fiber exhibited lower water absorption than other composites with the inclusion of MAPE. Overall, the results indicated that chemical treatment with NaOH and 3-APE with the presence of MAPE is a good approach towards the development of natural fiber composites.