Preparation And Performance Study Of Natural Plant Fiber Polymer Composite Board

With a wide range of raw material sources,plant fiber composite board has the advantages of being recyclable,non-toxic and non-hazardous,and excellent environmental performance,etc.,and has a broad application prospect.The application of plant fiber polymer composite board in the field of packaging and transportation to replace the traditional wooden packaging board will not only lead to a reduction in the consumption of wood resources,but also reduce production costs.In this paper,wood flour fiber,straw fiber,low density polyethylene(LDPE)and maleic anhydride grafted low density polyethylene(MAPE)were used as raw materials to prepare plant fiber polymer composite board by molding,and the study of suitable hot pressing temperature,optimal fiber addition ratio,suitable density,and microstructure of the components and strengthening mechanism within the composite panels were carried out.The main studies were as followed.(1)The wood flour fibers were mixed with low density polyethylene(LDPE)and maleic anhydride grafted low density polyethylene(MAPE)by roll opening,together with mold pressing to prepare wood flour fiber/LDPE composite board,and the effect of processing on the mechanical properties,water absorption and nail grip of the composite panels were investigated.The results showed that when the hot pressing temperature was 180 ℃,the bending strength and tensile strength of the composite board were 23.54 MPa and 16.12 MPa.Respectively,The alkali solution could remove part of the wax on the surface of wood flour fibers to rough up the fiber surface and improve the mechanical properties of the composite board.Improvement effect of maleic anhydride grafted polyethylene was stronger than KH550,with a more suitable addition ratio of 5%.When the wood flour fiber content was 50%,the bending strength and tensile strength of the composite board were improved by 30.56% and14.98%,respectively after third openings compared with first opening.The higher the wood flour fiber content,the higher the water absorption rate expansion rate of the composite board.(2)The straw/LDPE composite board were prepared by molding,and the effects of straw addition,pretreatment method,density,type and size of added straw long fibers on the properties of straw fiber/LDPE composite board were investigated.The result showed that alkali treatment could improve all properties of the composite board.Improving the density of the composite board was beneficial to improve its mechanical properties.Stripped straw shells were more effective in enhancing the composite board than direct shearing of straw.The addition of 7 cm long straw fiber and the addition amount of 25% was more significant to enhance the composite board.(3)Wood flour fibers were blended into straw and wood flour fiber blended straw fiber/LDPE composite board was prepared to study the effect of wood flour blending ratio and the lay-up of straw long fibers on the performance of composite board.The results showed that the bending strength and tensile strength of the composite board were 43.74 MPa and31.86 MPa respectively when the proportion of wood flour fiber doping in the composite board was 30%.The lay-up method of straw long fiber showed that the bending strength of composite board was better with X-Y-X lay-up,followed by X-X type and weakest with Y-Y type.The tensile strength of composite board was strongest with X-X type lay-up,followed by X-Y-X type,and weakest with Y-Y type.Straw long fiber to X-Y-X type lay-up way of composite board grip nail strength was better.