| As the new environment-friendly material,WPC is reinforced by biomass fibers or powder to compound with thermal plastic.It is processed by injection moulding,compression moulding or extrusion moulding.Nowadays,WPC products have been basically achieving industrialized production,and widely used in daily production and living environment.So far,many kinds of wood sources have been used for preparing WPC.In this paper,15 types of woody materials(poplar,eucalyptus,birch,radiate pine,larch,pinus sylvestris,chinese fir,wheat straw,rice straw,rice husk,bagasse,cotton stalk,moso bamboo,caragana microphylla,apple tree)have been selected from six kinds of wood resources(hardwood,softwood,agricultural wastes,bamboo,shrub,fruit tree)to explore the effect of lignocellulosic species and chemical composition on properties of WPC.The lignocellulosic fibers were prepared and the chemical components content were determined and corresponding WPC from each biomass materials were processed by extrusion moulding.The relationship between material types and chemical composition and properties of WPC was systematically studied.The main results were as follows:(1)The character absorption peaks of cellulose,hemicellulose and lignin were present in all of the selected 15lignocellulosic FTIR spectra.Spectra of the hardwood,agricultural wastes,shrub and fruit tree showed the presence of a stretching band for siringyl type lignin at 1230 cm-1 and 835 cm-1.The band at 1270 cm-1 due to guaiacyl type lignin was present in softwood.The peaks at approximately 2? = 14°,16°,23°,and 35°,which were assigned to the[101],[101],[200],and[040]were observed in all lignocellulose diffractogram.(2)Chemical component of 15 kinds of lignocellulosec fibers from 6 biomass materials was determined,the results showed that,the hollocellulose,cellulose and hemicellulose content in hardwood is higher than softwood,agriculture wastes,moso bamboo,caragana microphylla and apple tree.The softwood exhibited higher lignin content than other materials.Wheat straw,rice straw,cotton stalk and caragana microphylla showed higher alcohol extractives content.The ash content of rice straw and rice husk was higher.(3)Morphological analysis by SEM showed that,the interface between particles and matrix in WPC reinforced by wheat straw,rice straw,rice husk and caragana microphylla was clear.Wheat straw and rice straw particles in the matrix produced an aggregation.Many cells can be observed in rice husk/HDPE?cotton stalk/HDPE and caragana microphylla/HDPE.(4)Comparing the properties of WPC reinforced by different biomass materials.,the results showed that.Mechanical properties:WPC reinforced by poplar showed the best,agriculture wastes and shrub were poor.Rheological behavior:The eucalyptus/HDPE,birch/HDPE and radiate pine/HDPE showed better flowbility.Water absorption:The result was ranked as follows:cotton stalk/HDPE>wheat straw/HDPE>rice straw/HDPE>caragana microphylla/HDPE>moso bamboo/HDPE>rice husk/HDPE.Thermal stability:The first stage mass loss and final residue rate of agricultural wastes/HDPE were36?44%and 11.56?19.84%,respectively.The value of former was lower than other WPCs and the later was higher.Vicat softening point:WPC reinforced by agricultural wastes and shrub showed lower vicat softening temperature.The caragana microphylla/HDPE showed the lowest value of 69.6?Cand the poplar/HDPE and apple tree/HDPE showed the highest value of 97.4 and 97.2?,respectively.(5)Comparing the properties of WPC reinforced by different kinds of woody materials.In hardwood,the mechanical properties,thermal stability and water resistance of poplar/HDPE were better than eucalyptus/HDPE and birch/HDPE;in softwood,pinus sylvestris/HDPE showed poorest mechanical properties and thermal stability;in agricultural,wheat straw/HDPE exhibited lower mechanical properties and vicat softening temperature;cotton stalk/HDPE showed highest water absorption. |
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