The Preparation And Characterization Of Fast-growing Wood/Plastic Composites

The aim of this paper is to prepare fast-growing grass nano-modified wood-plastic composite material with obvious low carbon and environmental protection characteristics by warm compaction process based on single factor experimental results and response surface methodology,using fast-growing grass resources such as Pennisetum as base material,polyethylene(PE)as composite component and nano-zinc oxide/nano-corundum powder as strengthening factor,with a view to replacing natural rare wood and mechanical engineering materials as engineering materials,and further reducing people’s dependence on natural resources and mineral resources,alleviating resource shortage contradiction and reducing carbon emission through prolonging carbon fixation period of fast-growing grass cheap carbon sink resources such as Pennisetum.The main tasks completed are as follows:(1)Three kinds of base material powders of Pennisetum,Phyllostachys pubescens and Phragmites comnunis were prepared and their basic components were analyzed.It was found that the total cellulose and hemicellulose content(71.83)of Pennisetum was similar to the corresponding content(74.33)of Phragmites communis,both higher than that of Phyllostachys pubescens(66.62).The lignin content of Pennisetum(23.16)was higher than that of Phragmites communis(20.17),but lower than that of Phyllostachys pubescens(30.67).Pennisetum,as a grass resource,is widely distributed,cheap and easily available,but it is rarely used in the research field of biomass composite materials and is intended to be the main substrate of this study.(2)Based on the results of single factor experiments,regression analysis was carried out on the optimal levels and interactions of the three key factors affecting the warm pressing forming process conditions of fast growing grass wood plastic composites,including forming temperature,forming pressure and PE content.the quadratic multinomial mathematical models of the static bending strength,water absorption and apparent hardness of warm compaction sample were established respectively by using statistical methods,and the accuracy and credibility of the models were verified through verification experiments.Through regression analysis and experimental verification,the optimum technological conditions for warm pressing forming of fast growing grass wood plastic composites were determined:forming temperature 173℃,forming pressure 70MPa,PE content 10.5%,and holding time 30min.(3)Through the research on nano-modification of fast-growing grass wood-plastic composite material,it is found that nano-corundum powder has obvious improvement effect on the friction and wear properties of wood-plastic composite sliding bearing.when the content of nano-corundum powder is 6%,the effect is the best.The static bending strength,internal bonding strength,water absorption rate and apparent hardness of the nano-modified wood-plastic composite reached 63.73 MPa,4.95 MPa,2.19%and 90.51 HV respectively under the optimal warm compaction process conditions.(4)Through the research on the service performance of nano-modified wood-plastic composite material,the short wear-in period(about 7min),small friction coefficient(about 0.11)and the limit PV value of 161.7MPa.m xmin-1 of nano-modified wood-plastic composite sliding bearing have been realized.it is expected that the nano-modified wood-plastic composite sliding bearing can replace sintered bronze in the manufacture of light textile mechanical sliding bearing under certain working conditions.(5)Through wood-plastic composite,warm compaction and nano-modification,fast-growing grass nano-modified wood-plastic composite with a weight loss rate as low as 2.4%was obtained,and the anti-aging performance of wood-plastic composite was effectively enhanced.