Study On LDPE/Wood Flour Composites

Preparation of wood plastic composites (WPC) is one of the important methods to replace natural wood and recycle waste plastics. In this paper, the optimum contents of the additives in LDPE/wood flour composite was investigated. Based on the fore-going formulation, the relationship between the composition, the structure and properties of LDPE/wood flour composite foams was studied systematically. Depending on the SEM micrographs, the distributing regulation of the nucleation agent used in LDPE/wood flour composite foams was also discussed. In addition, the pilot study on the feasibility of waste plastics and other natural fibers used in WPC foams was carried out. The main works and conclusions were listed as following:1. LDPE /wood flour composite was prepared from LDPE and wood flour, the effects of the content of the wood flour, the effects of the type and content of surface treatment agent on the properties of WPC were studied. The results showed that the overall property of the composite was the optimum when the content of the wood flour was 30 phr, and the content of the surface treatment agent C was 1% of the mass weight of the wood flour.2. The effects of the content of exothermic and endothermic foaming agent on the properties of LDPE/wood flour foams were studied, and the reducing of the specific weight of the composite by the use of foaming agent was studied tentatively. The results showed that the use of chemical foaming agent(CFA) could decrease the specific weight of the composite effectively and improve the impact property of thecomposite . As to the blowing effect, the endothermic-exothermic balanced CFA was better than exothermic CFA.3. The effects of nucleation agents T, F and G on the properties and microstructure of LDPE/wood flour composite foams were investigated respectively. Nucleation agent T was found to produce the most fine and uniform microstructure, while nucleation agent F had the least blight on the mechanical properties of the foams. By the SEM micrographs , the particles of nucleation agent were found to scatter on the interface between the wood fiber and matrix.4. The feasibility of waste plastics and other natural fibers used in WPC foams was studied tentatively. The results showed the overall property of waste plastic/wood flour composite foams was close to that of LDPE/wood flour composite foams. It was also proved that other natural fibers had the potential to substitute for wood flour as the filler of WPC foams.