Study On The Molding Process And Properties Of PP Composites Filled With Lignocellulose

Wood Plastic Composites (WPC) is a new kind of environmental composites; because of its environment friendly and sustainability advantages, the development and application of this new composites has been develpoed rapidly in recent years. This new kind of environmental composites feel like natural wood, and have better physical properties than wood. It can be drilled, cut, planed, milled and napped by tools. It is widely used in architecture molding board, Vehicle Shipping, furniture industry, packaging transportation and so on. Preparation of wood plastic composites is one of the important methods to replace natural wood and recycle waste plastics.In this paper, wood-fiber, bamboo fiber, rice husks and rice-straw fiber were used as fillings to fill PP. Many kinds of composites were made by high-temperature molding process. Some experiments about the composites were done, and the compatibility and the microcosmic shape were observed by stereomicroscope. The main work and conclusions were as follows:(l)Molding process of PP/lignocellulose composites were studied, and the molding process parameters were optimized. The results showed that with20Mpa high pressure,180℃high-temperature and15min pressure holding time, the combination properties of composites were better.When the content of lignocellulose were high, molding pressure and temperature should be enhanced in order to the properties of composites can meet requirements.(2) The effects of contents of rice straw on mechanical properties and physical and chemical properties of PP/rice straw composites were studied. The results showed that when the contents of rice straw were50%, the tensile strength, modulus of rupture and modulus of bending of composites were best, and the impact strengh and hardness were good. With the rice straw content increased, mechanical properties of the composites decreased gradually. However, moisture absorption, moisture content, water absorption and thickness swelling and24h water absorption had a increasing trend.stereomicroscope photos showed that the phenomenon of twist and drawbench between rice straw and PP when the contents of rice straw were low, and the wrapping capability was very good.(3) The effects of different lignocellulose on mechanical properties and physical and chemical properties of the composites were studied. The results showed that the composites which was filled in cedar fiber with larger surface roughness and aspect ratio had good combination property while the composites filled in rice husk and bamboo fiber were just mediocre.(4) The effects of mechanical properties and physical and chemical properties of composites of six different lignocellulose sizes were studied. The results showed that the filling had uneven dispersion in PP when it was smaller, and the mechanical properties would be worse; if the filling was too big, there would be more inanition cavern and also could influence the mechanical properties. When the rice husks whose granularity was60mesh was used to fill PP,its integrative capability would be the best.