Effect of a silane coupling agent on the properties of white rice husk ash-polypropylene/natural rubber composites

White rice husk ash (WRHA)-polypropylene (PP)/natural rubber (NR) composites were prepared using a Brabender Plasticorder at 180 degreesC and a rotor speed of 50 rev min(-1), The mechanical and water-absorption properties were studied. The incorporation of WRHA into the PP/NR matrix has resulted in the improvement of the tensile modulus; however, the tensile strength, elongation at break and stress at yield decreased with increasing WRHA loading. Poor filler matrix interactions are believed to be responsible for the decrease in the properties. Incorporation of a silane coupling agent, 3-aminopropyl triethoxysilane (3-APE), improved tensile modulus, tensile strength and stress at yield of the composites. Water-absorption studies indicate that the use of the coupling agent reduced the amount of water absorbed by the composites. (C) 2001 Society of Chemical Industry.