Aesculap AG, Research & Development, 78532 Tuttlingen, Germany.
Ludwig Maximilians University, Department of Orthopaedics Surgery, Physical Medicine & Rehabilitation, Campus Grosshadern, 81377 Munich, Germany.
Biomed Res Int. 2020 Mar 23;2020:2568428. doi: 10.1155/2020/2568428. eCollection 2020.
Previous studies have shown that increased cross-link density, reduced free radicals, and increased antioxidant grafting resulting from electron-beam irradiation at elevated temperatures improved the wear performance and the oxidative stability of vitamin E blended UHMWPE. The current study explores the impact of elevated irradiation temperature on vitamin E blended UHMWPE using X-ray. We hypothesize that the effects of temperature would be similar to those observed after electron-beam irradiation due to the relatively high dose rate of X-rays. Two X-ray doses of 80 and 100 kGy and two irradiation temperatures, that is, room temperature and 100°C were considered. The reference was Vitelene®, a vitamin E stabilized polyethylene cross-linked with 80 kGy by e-beam at 100°C. Oxidation index and oxidation induction time, as well as cross-link density, gel fraction, and -vinylene index, were determined, as the oxidative and network properties are decisive for the long-term implant performance. Gel fraction and oxidation induction time were significantly improved subsequently to warm irradiation in comparison with the material irradiated at room temperature. In conclusion, X-ray irradiation at elevated temperatures resulted in an increase of cross-linking and oxidative resistance of vitamin E stabilized polyethylene comparable to those of e-beam irradiated UHMWPE.
先前的研究表明，辐照温度升高导致的交联密度增加、自由基减少和抗氧化剂接枝增加，改善了维生素 E 共混 UHMWPE 的耐磨性能和氧化稳定性。本研究使用 X 射线探讨了辐照温度升高对维生素 E 共混 UHMWPE 的影响。我们假设由于 X 射线的相对高剂量率，温度的影响将类似于电子束辐照后观察到的影响。考虑了两种 X 射线剂量（80 和 100 kGy）和两种辐照温度，即室温（room temperature）和 100°C。参比物为 Vitelene®，这是一种维生素 E 稳定的聚乙烯，通过 100°C 的电子束辐照交联，剂量为 80 kGy。测定了氧化指数和氧化诱导时间，以及交联密度、凝胶分数和 -乙烯基指数，因为氧化和网络性质对长期植入物性能至关重要。与在室温下辐照的材料相比，在温暖辐照后，凝胶分数和氧化诱导时间显著提高。总之，高温 X 射线辐照导致维生素 E 稳定的聚乙烯的交联和抗氧化性增加，与电子束辐照 UHMWPE 的增加相当。
