Influence of protein and lipid concentration of the test lubricant on the wear of ultra high molecular weight polyethylene

To gain a better understanding of the ultra-high molecular weight polyethylene (UHMWPE) wear mechanism in the physiological environment, the effects of protein and lipid constituents of synovial fluid on the specific wear rate of UHMWPE were examined experimentally. The multidirectional sliding pin-on-plate wear tester was employed to simulate the simplified sliding condition of hip joint prostheses. Bovine serum γ-globulin and synthetic l--DPPC were used as model protein and lipid constituents of synovia, respectively. Results of the wear test indicated that the UHMWPE wear rate primarily depended on the protein concentration of the test lubricant. Lipids acted as a boundary lubricant and reduced polyethylene wear in the low protein lubricants. However, the polyethylene wear rate increased with increasing lipid concentrations if the protein concentration was within the physiological level. Increased interactions between protein and lipid molecules and lipid diffusion to polyethylene surface might be responsible for the increased wear.     

超高相对分子质量聚乙烯纤维研究进展

介绍了超高分子质量聚乙烯纤维的制备、表面改性及应用的研究进展 ,指出了今后超高分子质量聚乙烯纤维的研究及应用的发展方向     

硅烷交联超高分子量聚乙烯

采用硅烷对超高分子量聚乙烯(UHMWPE)进行交联改性，系统地研究了交联UHMWPE的凝胶率、熔点、结晶度、力学性能与耐磨性。结果表明，硅烷偶联剂导致了UHMWPE的交联，使UHMWPE的凝胶率提高。当硅烷含量较低时，UHMWPE的熔点增高、结晶度增大；当硅烷含量较高时，UHMWPE的熔点、结晶度呈下降的趋势；硅烷交联导致了UHMWPE材料的模量和强度提高，磨耗率降低；当硅烷含量较高时，交联UHMWPE材料的力学性能和磨耗率均变差；当硅烷含量为0．2份～0．4份时，交联UHMWPE材料的综合性能最佳。     

超高分子量聚乙烯纤维/有机玻璃复合材料摩擦磨损性能研究

用真空浸渍法成功制备出了超高分子量聚乙烯纤维／有机玻璃(UHMWPE／PMMA)复合材料，并对基体材料PMMA，单向超高分子量聚乙烯纤雏／有机玻璃复合材料以及三维编织超高分子量聚乙烯纤维／有机玻璃(即UHMWPE3D／PMMA)复合材料的摩擦磨损性能进行了研究。实验证明UHMWPE／PMMA复合材料具有优良的摩擦磨损性能。经过纤维增强的复合材料的摩擦磨损性能优于基体材料，三维编织纤维增强的复合材料其磨损远小于单向纤维增强的复合材料，但其摩擦系数没有显著变化。     

UHMWPE纤维/LDPE复合材料防弹性能及机理研究

本文探讨了用超高分子量聚乙烯（UHMWPE）纤维增强低密度聚乙烯（LDPE）复合材料的防弹性能，研究了不同基体含量对复合材料防弹性能的影响。实验证明，UHMWPE纤维／LDPE复合材料具有较好的防弹性能，其最佳的基体含量在26％左右。同时，本文还通过分析防弹片材的断裂区域及复合材料的防弹机理确定了弹丸的变形情况和靶片“背凸”在防弹作用中的贡献。     

PP/UHMWPE共混物力学性能的研究

采用不同结构的聚丙烯(PP)分别与不同流动性能的超高摩尔质量聚乙烯(UHMWPE)进行共混，对共混物的力学性能进行了研究。发现PP和UHMWPE类型的适当匹配对共混物性能的提高非常重要。流动性较好的UHMWPE对熔体质量流动速率较小的嵌段共聚型PP(PPB)增韧增强效果突出，常温缺口冲击强度可达74．2kJ／m^2，断裂伸长率大于700％；同时共混物的强度和刚性也有一定程度的提高。在PPB／UHMWPE二元共混物中加入适当线性低密度聚乙烯(LLDPE)，能够起到“减粘”和“增容”作用，有利于共混物性能，尤其是抗冲性能的进一步提高。     

Harnessing the Melting Peculiarities of Ultra‐High Molecular Weight Polyethylene Fibers for the Processing of Compacted Fiber Composites

Summary: Compacted fiber composites offer unique properties due to their lack of an extraneous matrix. The conditions of processing ultra‐high molecular weight polyethylene (UHMWPE) fibers were simulated in a heated pressure cell. In situ X‐ray diffraction measurements were used to follow the relevant transitions and the changes in the degree of crystallinity during melting and crystallization. The results strongly support the suggestion that the hexagonal crystal phase, in which the chain conformation is extremely mobile on the segmental level, constitutes the physical basis of compaction technologies for processing UHMWPE fibers into a single‐polymer composite. This report suggests that using a pseudo‐phase diagram outlining the occurrence of different phases during slow heating and the degree of crystallinity can provide valuable insight into the technological parameters relevant for optimal processing conditions.

Degree of crystallinity as a function of pressure and temperature in a region relevant to compaction processes.     

原位聚合不同填料/UHMWPE及其性能研究

用原位聚合法制备了分别加入纳米碳化硅、玻璃微珠、二硫化钼等填料的超高摩尔质量聚乙烯复合材料, 测试了其性能,并对原位聚合法和共混法的复合材料材料性能进行了对比。结果表明:该复合材料不但基本保持了超高摩尔质量聚乙烯原有的优异性能,而且与纯超高摩尔质量聚乙烯相比,该复合材料的硬度、热变形温度等都有不同程度的提高。原位聚合法制备的复合材料比共混法的综合性能高。     

高强度聚乙烯纤维绳索的制备研究

研究了纤维的捻度及浸胶处理对超高相对分子质量聚乙烯 (UHMWPE)纤维力学性能及摩擦磨损性能的影响。结果表明 ,UHMWPE纤维的断裂强力随着纤维捻度的增加而减小 ,纤维浸胶处理后的断裂强力增大 ;当UHMWPE纤维中改性氯丁胶粘剂或聚氨酯胶粘剂的含量为 6%时 ,其断裂强力分别增加 17.2 %或 13 .9% ,聚氨酯胶粘剂处理过的UHMWPE纤维的耐摩擦磨损性能最好。