Thermal and Mechanical Properties of Novel Composites of Methyl Silicone Polymer and Partially Ceramized Rice Bran

Rice bran (RB), rich in carbon and silicone, is an agricultural waste that is abundantly available in rice producing countries. In this work, composites of a preceramic methyl silicone resin (MSR) and RB were prepared by blending powdered RB with a molten MSR at 110 degrees C at various ratios in a Brabender-type static mixer. Composites were made from them by compression molding and cross-linking at 260 degrees C under 20 MPa pressure. The thermal, mechanical, and chemical properties of the produced composites were assessed by thermogravimetric analysis, scanning electron microscopy, and FT-IR and by measuring compressive strength and hygroscopic expansion. It was found that RB was partially ceramized and decomposed to carbonaceous materials during cross-linking. The water absorption and hygroscopic expansion of the MSR/RB composites were increased but the compressive strength was decreased with an increase in the weight % of RB. The highest compressive strength was shown by the composites made from the 50/50 blends, which was 27.61 MPa. The developed composites showed an excellent compressive strength and also very low water absorption and hygroscopic expansion.