Radiation processed sawdust clay plastic composite

Wood sawdust has been applied to manufacture the sawdust clay plastic composite (SDCPC) by radiation process for the purpose of disposing large amount of wood sawdust waste material. The process comprises the impregnation of liquid vinyl monomers into the completely dried molded sawdust-clay specimens followed by exposure to Co-60 gamma-radiation to induce graft-copolymerization of the impregnated vinyl monomers onto the sawdust-clay matrix. The comonomer system of unsaturated polyester and vinyl compounds was found to be the ideal impregnating monomer for the preparation of the SDCPC from the viewpoint of the technological and economical advantages. The SDCPC material has a variety of the sawdust content which enables the composite to have wide range of mechanical properties, e.g., 410 to 1100 kg/cm2 in compressive strength, 120 to 380 kg/cm2 in tensile strength and 0.32 to 4.41 kg/mm2 in static bending strength. The SDCPC having higher content of clay (more than 50% by wt.) was found to have the properties of stronger mechanical strength, good resistance to strong mineral acids and weather-proof. The kinetic mechanisms of the radiation induced graftcopolymerization of vinyl monomers was also investigated and discussed. (author)