The Study Of Process And Properities Of Rigid Polyvinyl Chloride/Wood-Flour Composites

Wood plastics composites are widely increased recently because they are environment friendly.The higher density and low impact iesistence compared to unfilled PVC/or natural solid wood may prevent PVC/wood-flour full market potential.In this dissertation,different approaches including impact modification,Continuous extrusion foaming processes with CFA(chemical foam agent)have been examined to overcome some of these drawbacks.The effect of wood-flour addition levels on the mechanical and processing properties of rigid PVC/wood-flour composites were examined.With the content of wood-flour increased, it will be decrease impact strength and tensile properties of rigid PVC/wood-flour .The effect of impact modifier types(crossl inked vs. uncrosslinked)and addition levels on the mechanical properties of rigid PVC/wood-flour composites were examined. Crosslinked modifiers were more effective and efficient in improving the impact resistance of rigid PVC/wood-flour composites than the uncrosslinked modifier.Rigid particle can be significantly improved the impact strength of rigid PVC/wood-flour without degrading the tensile properties.Foaming is an effective method for reducing the density of polymers.The effects of CFA(endothermic vs. en-exdothermic) and concentrations on density and cell morphology of extrusion-foamed neat rigid PVC and rigid PVC/wood-flour composites were studied.The experiment result indicated that en-exothermicfoaming agent is more efficient in decressed the density of rigid PVC/wood-flour composites than the endothermic foaming agent. Regardless of CFA types, the impact strength reduction achieved was not influenced by the type of the foaming agent with increased CFA concentration.The effect of lubricant processing properties of rigid PVC/wood-flour composites were examined. From the experiment result, the percent of lubricant is reached 1.0,the maximal tarque is TAF>TAS-2A>ZB-74 >TAS-2A+paraffin>paraffin, plastic time is TAS-2A>ZB-74>TAF >TAS-2A+paraffin> paraffin.