UHMWPE Composite Material for Joint Implants

描述（由申请人提供）：在SBIR二期项目中，超高分子量聚乙烯（UHMWPE）关节植入材料的机械性能和疲劳相关性能将通过创建碳增强的复合材料来改善。超高分子量聚乙烯（UHMWPE）长期以来被广泛用作关节植入物的磨损表面，通过聚乙烯链的交联进一步提高了其耐磨性。然而，交联过程也会降低一些机械性能，包括韧性、疲劳和屈服强度。通过上述方法将碳增强剂加入到超高分子量聚乙烯中，可以在不影响其低磨损率的情况下提高超高分子量聚乙烯的强度、抗裂纹扩展能力和抗蠕变能力。碳增强剂将赋予超高分子量聚乙烯基体无与伦比的尺寸稳定性和韧性。此外，由于磨损表面（主要）仍然是超高分子量聚乙烯（UHMWPE），超高分子量聚乙烯（UHMWPE）的优异耐磨性即使不能通过机械增强得到改善，也将得到保持。在第一阶段，通过在不同地层条件下制备复合材料，然后评估其机械和摩擦学性能，验证了其中的一些假设。如果新的超高分子量聚乙烯材料的性能符合预期，其好处将包括更持久的植入物，更不容易发生机械故障。因此，复合材料将需要更少的修改程序，并保持更长时间的功能，这是一个关键的需求，因为预期寿命的增加导致人们比他们的植入物更长寿。

DESCRIPTION (provided by applicant): In this SBIR Phase II project, the mechanical and fatigue-related properties of ultrahigh molecular weight polyethylene (UHMWPE) joint implant materials will be improved by creating a composite material with carbon reinforcements. UHMWPE has long been widely used as wear surfaces in joint implants, and further improvements to its wear resistance have been obtained by cross-linking the polyethylene chains. However, the cross-linking process also degrades some mechanical properties, including toughness, fatigue and yield strengths. Incorporating carbon reinforcements into UHMWPE through the manner described will improve the strength, crack propagation resistance and creep resistance of UHMWPE without compromising its low wear rate. The carbon reinforcements will impart unmatched dimensional stability and toughness to the UHMWPE matrix. Moreover, as the wear surface remains (primarily) UHMWPE, the outstanding wear resistance of UHMWPE will be maintained, if not improved through the mechanical enhancements. Several of these hypotheses were validated during Phase I by preparing composite materials under various formation conditions, and then assessing their mechanical and tribological properties. Should the new UHMWPE materials perform according as expected, the benefits would include longer-lasting implants that are less prone to mechanically-induced failure. The composite materials would therefore require fewer revision procedures and maintain functionality longer, a critical need as life expectancy increases are causing people to outlive their implants.