Thesis (M.Sc.)--Chulalongkorn University, 2004

This research work involved the preparation of the polymer composites made from unsaturated polyester resin and rice straw and from unsaturated polyester resin and surface modified rice straw with maleic anhydride (MA) and vinyltriethoxy silane (VTS). In the process of surface modification, the rice straw was treated with 10, 30, and 60% of MA and of VTS for improvement of the interfacial adhesion and compatibility between rice straw and polymer matrix. The prepared composites were investigated their mechanical properties and fracture surface morphology. It was found that mechanical properties of composite containing MA treated rice straw displayed better tensile strength, flexural strength, and impact strength than VTS treated rice straw and untreated rice straw composites. A 70:30 composite of unsaturated polyester resin and 30% MA treated rice straw showed the highest mechanical properties compared to those composites. The fracture surface morphology of 30% MA treated rice straw composites showed better compatibility and interfacial adhesion than untreated and VTS treated rice straw composites. Moreover, the study found that the water absorption of MA and VTS treated rice straw composites can be reduced compared to the untreated rice straw composite, approximately 29% and 20% respectively