Jufriah. Optimization of Sawdust Utilization of Red Meranti (Shorea spp.) as Raw Material for Wood-Plastic Composite with a Mixture of Polyethylene and Polypropylene Matrix (supervised by Rudianto Amirta, Wiwin Suwinarti and Isna Yuniar Wardhani).
The potential of sawdust in wood processing is quite large, but its utilization is limited and not maximized. Efforts are needed to utilize sawdust into added value products that use sawdust as a raw material for wood-plastic composites within plastic as matrix. The objectives of this study were: 1) to determine the best combination of various treatment factors (NaOH concentration, polyethylene and polypropylene plastic ratio composition, and temperature pressing) to obtain best physical and mechanical properties of wood-plastic composites; 2). to analyze the bonding structure of plastic and sawdust of products and 3). to determine the optimal conditions for making wood-plastic composites from red meranti sawdust in various treatments to produce the best wood-plastic composites. Pre-treatment of sawdust by soaking in 1-3% NaOH for 2 hours, the composition of polyethylene (HDPE) and polypropylene (PP) consists of 5
compositions, pressing temperature 180°C (in the initial study) and 160°C, 180°C, 200°C (in the optimization study), a pressure of 30 bar and a pressing time of 20 minutes. The coupling agent is 3% Maleic Anhydride (MAH). Sampel preparation and testing accordance to several ASTM standards and microscopic analysis using the Phenom Pro X SEM (Scanning Electron Microscope) and the NIKON SMZ 645 Stereo Microscope. Factorial experimental design and an advanced LSD were use to data analysis and Response Surface Methodology were used with the Design Expert 13 application. Conclusions can be drawn, as follows: 1). The best physical properties of wood-plastic composites were found in sawdust without pre- treatment with a composition of 75% HDPE: 25% PP at a pressing temperature of 200°C. The best mechanical properties is treatment by soaking 1% NaOH for 2 hours with same composition and temperature as physical properties; 2). According to SEM analysis, sawdust and plastic interface occurred well on sawdust pre-treated with 1% NaOH soaking for 2 hours with 75% to 100% polyethylene (HDPE) composition in pressing temperature 200°C; 3). The optimum process conditions for the manufacture of wood-plastic composites from sawdust of red meranti by compression molding or thermoforming (pressing) are soaking sawdust with 1.30% NaOH, with a composition of 77.02% polyethylene (HDPE) and 22.98% polypropylene (PP), and temperature pressing 199.86ºC; 4) The physical and mechanical properties of wood plastic composite by optimum condition process were fulfill theses standards (SNI 03- 2105:2006, JIS A 5908:2003, JIS A 5741:2006 and ASTM D6662:2001). The suggestion of study are 1). Wood-plastic composites production of red meranti sawdust by compression molding or thermoforming process delivered by soaking sawdust in 1.30% NaOH, HPDE:PP composition is 77.02%:22.98% and a pressing temperature of 199.86ºC; 2). To complete the information on the results of this study, additional research with variations and concentrations of additives or coupling agents, as well as the ratio of sawdust to plastics, is required; another study is required for the pre-treatment of sawdust using other types of chemicals or methods; and 3). Extraction results from soaking sawdust can be used as a natural wood coloring agent.