Dependence of polyurethane content on physical and mechanical properties of wood fiber/palm kernel shell composites
Wood-based composites with different ratios of wood fiber (WF)/palm kernel shell (PKS) and polyurethane (PU) content have been prepared using the wet-process method. Samples of WF85/PKS15 and WF75/PKS25 were fabricated where each sample was applied with 20% and 70% of PU contents and its physical and mechanical properties had been studied. The physical results show that the samples with 70% of PU content were denser, had low porosity, low moisture content, and low water absorption. Surface morphology observation shows both series samples with high PU content tend to form tube-like shape with different diameter. In mechanical studies, generally, the sample with high PKS and PU possesses high flexural strength, flexural modulus, tensile strength, tensile modulus, and hardness. However, the increased of PKS content in the composite reduces the tensile strength for both samples with 20% and 70% of PU. The effects of the binder and palm kernel shell in the composite were also explained. Based on the Japanese Industrial Standard (JIS) A 5905 standard, the sample composites meet the requirement under medium density fiberboard (MDF) category and classified as board type 5 which suitable as furniture, house, and automotive interior design and construction materials.