Study On Structure And Properties Of Ultra-High Molecular Weight Polyethylene Composites

At present, with the development of science and technology, material science is developing in the direction of high performance, functionality and composite. Polymer-matrix composite material developed rapidly and received high attention for its excellent performance and extensive applications. At the beginning of the thesis, the present situation of modifying and application on Ultra high molecular weight polyethylene (UHMWPE) were summarized. Because of the molecule weight of UHMWPE is very high, it was difficult to process. From blending, composite materials, UHMWPE could be obtained in different properties and applications. The main purpose of the subject was to lower the cost of UHMWPE, on the other hand, enhance the rigid properties of the "UHMWPE". Meanwhile, several processing methods of UHMWPE were summarized in the thesis. The relationship between structure and properties was the main significance of the research.The glass microspheres were treated by silicon coupling agent processing and the UHMWPE composites’thermal properties, mechanical properties and wear-resisting properties were studied, which showed that surface treatment of got effective dispersion, and the vicat softening temperature of the composites were greatly improved with the increase of the glass beads content. It was found that a web of glass bead/UHMWPE/coupling agent was formed, which played a significant role in improving the heat resistance of the composites. The web also increased the entanglement density in the amorphous region and thereby had an effect on increasing tensile strength, impact strength and wear resistance property.UHMWPE/PP blends were prepared by mixing heat resistance PP, wear resistance agent and UHMWPE, and the effects of PP content and wear resistance agent on the flow, mechanical and wear resistance properties of UHMWPE/PP blends were studied. The results showed that PP could improve the fluid performance of UHMWPE effectively. The load deformation temperature and vicat softening temperature of the blend were improved with the increase of PP content. After adding the wear resistance agent, when the mass fraction of PP was 50%, the tensile strength of the blend was maximized, but the elongation at break was minimized, and the impact property of the blend decreased with the increase of PP content. PP decreased the wear resistance property of UHMWPE, but the addition of wear resistance agent could retain the high wear resistance property of UHMWPE and had no effects on the flow and mechanical properties of the blend.Finally, the UHMWPE composites’mechanical properties were studied. It showed that the composites’tensile strength made an improvement of 24.76%, the impact strength of the composite made an improvement of 30.52%. SEM analysis showed that, with the increases of the glass fiber content, fiber oriented easier along one direction. The higher the degree of fiber orientation, the more energy absorbed by the material, the greater impact strength of the material was fractured, which agrees with the situation of improvement of composites’mechanical properties.