Preparation And Performance Of Modified Ultra-high Molecular Weight Polyethylene Composites

Ultra High Molecular Weight Polyethylene(UHMWPE)is a thermoplastic engineering plastic with high application potential and wide market demand,which can be adapted to the use environment with high requirements for abrasion resistance,low temperature resistance and corrosion resistance.However,it cannot meet the applications in some engineering fields with high temperature and high requirements for hardness and strength.It is the focus of modification work to maintain the original excellent performance as much as possible while making appropriate modification to UHMWPE temperature resistance and rigidity,etc.The preparation of multi-layered composites by adding nanomaterials and other materials is an effective way to improve and enhance the performance of UHMWPE materials.In this paper,halloysite nanotubes(HNTs)with unique hollow tubular structure were selected as the reinforcing phase,UHMWPE/HNTs composite sheet was prepared by melt extrusion by choosing aluminate coupling agent to pretreat HNTs,dendrimer and polyethylene wax as dispersant.On the basis of this,UHMWPE/PP/HNTs ternary blended composite sheet was prepared by by using high temperature resistant polypropylene(PP).In addition,the preparation of UHMWPE fiber self-reinforced composite sheet was also tried to explore the preparation of UHMWPE fiber self-reinforced composite sheet by molding method.After testing and analysis,the following conclusions were drawn:(1)When the HNTs content is5.0%,the composite has the relatively good performance.Heat deflection temperature increased by 29.4%,tensile strength increased by 30.1%,bending strength increased by 10.2%,notched impact strength increased by 20.1%,Shore hardness increased by 6HD,and crystallinity increased by 7.9%.Continuing to increase the content of HNTs,the properties of the composites were all degraded to different degrees.The addition of dendrimer and polyethylene wax can improve the dispersion of HNTs,and the addition of aluminate coupling agent can make the wettability of UHMWPE with HNTs better,which further improves the properties of the composites.(2)In the UHMWPE/PP/HNTs ternary blend system,,when the addition of HNTs is 1.5%and the addition of PP is 20%,the tensile strength increases by 58.6%,the heat deflection temperature increases by 79.0%,and the crystallinity and thermal stability both go up,the notched impact strength has decreased.Compared with the binary system of UHMWPE/HNTs,the comprehensive performance of UHMWPE/PP/HNTs ternary blended composites is better,which is the result of the synergistic effect of PP and HNTs.(3)UHMWPE fiber in the hot pressing process,.the oriented structure of the fibers is anchored down in the UHMWPE resin and plays a self-reinforcing role.With the increase of fiber content,the mechanical properties and temperature resistance of the composite sheet are on the rise.Long fibers are more effective than short fibers in enhancing the mechanical properties of composite sheets,and staggered arrangement is more effective than unidirectional arrangement in improving the heat resistance of composite sheets.