Environmentally Friendly Wood Fiber Reinforced Pvc Composite Materials And Molding Technology

This article selects to add100phr wood flour fibers,30phr recycled plastics and70phr fresh polyvinyl chloride (PVC) as matrix,prepare for wood-plastic composite.By adjusting each component content of the formula and conditions of molding process, the mechanical properties of materials, microstructure of section and the situation of thermal weightlessness were investigated by use of impact testing machine, electronic universal testing machine and scanning electron microscope.The formula,formation technology and the physical properties of the products were studied systematically.1.The mobility, plasticization and package roll of material are more easily when seven PVC resin is mixed with wood powder than three or five; When the scope of wood powder particle size is60to100mesh,the tensile strength of wood-plastic composite is16.27MPa which is the largest.Bending strength and impact strength reduce when wood powder particle size decrease.Coupling effect is the best when use1.4phr titanate coupling agent deal with wood powder fiber. The mechanical properties improve significantly.When add DOP20phr,CPE12phr, CaCO310phr, the combination property of material is the best.2.Bending strength affected by the mold temperature is stronger than the molding time and molding pressure is minimal.When hot pressing temperature is170℃,the liquidity of plastic melt is very good. Meanwhile,on that temperature,it can avoid the degradation of PVC macromolecule and reduce the carbonization of wood powder fibers,give full play to the enhance role of wood fiber,the maximum bending strength of material is30.69MPa.When the briquetting pressure is10MPa,cost of manufacture,residual stress in the products and dimensional stability can be controlled in a certain range.The comprehensive results is fine.When Hot pressing time is12min, the growth rate of bending strength is reduced, and at that time the bending strength is30.42MPa;3. Water resistant, heat resistant properties and combustibility of material sample were investigated by density test, vicat softening point test and combustion performance test.Results are as follows:The density of wood plastic composite sample is0.96g/cm3;vicat softening point is96.1℃;The average inflation rate is0.43%after absorbing water,the bibulous rate is3.52%on average,the bending performance of material was reduced by10.88%before and after water absorption. Combustibility is good; 4,The thermal weightlessness condition of sample was inspected, the result is as follows:The weightlessness is divided into three stages,The weightlessness rate of first phase is30.7%,including the volatilization of small molecules like plasticizer,decomposition of PVC long-chain to HC1gas,carbonation decomposition of part of the wood powder;The weightlessness rate of second phase is30.3%,mainly includes carbonation decomposition of most of the wood powder;The weightlessness rate of third phase is18.8%,mainly includes the fracture weightlessness of PVC main chain.5.The section of material had been observed by scanning electron microscope,distribution of wood fiber is evenly.Bonding surface between wood fiber and matrix resin is fuzzy,wood fiber with a strong anisotropy along different directions,and break up with materials at the same time,give full play to the role of the filling enhancement.The fracture density is very large,local wire drawing is found,ductile fracture is very obvious, the comprehensive performance of material is excellent.