Department of Materials Science and Technology, Instituto de Investigación en Ingeniería de Aragón I3A, Universidad de Zaragoza, 50018, Zaragoza, Spain.
Centro Universitario de la Defensa de Zaragoza, Academia General Militar, Zaragoza, 50090, Spain.
J Mech Behav Biomed Mater. 2021 Mar;115:104248. doi: 10.1016/j.jmbbm.2020.104248. Epub 2020 Dec 7.
Ultra-high molecular weight polyethylene (UHMWPE) is a relevant thermoplastic in industry and a well-proven standard biomaterial in joint replacements. To enhance its tribological properties while preserving its bulk ones, composite coatings on a UHMWPE substrate were prepared using non-functionalised graphene nanoplatelet (GNP) at reinforcement concentration of 0.1-5 wt% and two mechanical mixing techniques (ball mill or blade mixer) with different consolidation temperatures of 175-240 °C. Changes in morphology and size of the UHMWPE particles before hot-pressing were observed in function of the mechanical mixing techniques applied. Wear rate was affected by graphene content, reaching a minimum at 0.5 wt% GNP, with a reduction of 20 and 15%, for ball milling and blade mixer, respectively. However, blade mixer increased the wear rate by around twice respect the ball milling results, for all the studied materials. The coefficient of friction decreased notably, by ~25%, below 3 wt% GNP content, and hardness increased by 24%, regardless of the mechanical mixing process used. Finally, consolidation temperature had a positive influence on wear rate at temperatures of around 195 °C, which could be related to the free radical scavenger effect of the GNP.
超高分子量聚乙烯（UHMWPE）是工业中一种重要的热塑性塑料，也是关节置换中经过充分验证的标准生物材料。为了提高其摩擦学性能而不影响其本体性能，采用非功能化石墨烯纳米片（GNP）作为增强剂，浓度为 0.1-5wt%，通过两种不同的机械混合技术（球磨或叶片混合），在 175-240°C 的不同固结温度下，在 UHMWPE 基底上制备了复合涂层。观察到热压前 UHMWPE 颗粒的形貌和尺寸随机械混合技术的变化而变化。磨损率受石墨烯含量的影响，在 0.5wt% GNP 时达到最小值，球磨和叶片混合分别降低了 20%和 15%。然而，对于所有研究的材料，叶片混合比球磨的磨损率增加了约两倍。摩擦系数显著降低，在低于 3wt% GNP 含量时降低了约 25%，而硬度则增加了 24%，无论使用哪种机械混合工艺。最后，固结温度在 195°C 左右对磨损率有积极的影响，这可能与 GNP 的自由基清除剂效应有关。
