In this paper, three commercial polymers (polytetrafluoroethylene [PTFE], polyetheretherketone [PEEK], and polyimide [PI]) were irradiated by gamma rays in the ambient air. The changes in microstructure, mechanical, and tribological properties of these three polymers after irradiation were investigated comparatively. The results display that both the surface and internal structures of PTFE are degraded due to the irradiation chemical reaction, and the molecular chain scission at the surface is more severe than that at its internal as a result of the involvement of oxygen. The oxidative degradation also plays a dominant role in the PEEK surface, but the molecular chain crosslink is dominant in the PEEK internal. The top layer of PI also shows the characteristics of oxidative irradiation degradation, but its internal exhibits excellent irradiation resistance and no structure change occurs even at irradiation doses up to 20 MGy. The microhardness and scratch resistance of irradiated surfaces for all three polymers decrease but only the scratching damage mode of PTFE changes after irradiation. Friction experiments show that the friction coefficients of PTFE increase but that of PEEK decrease after irradiation. The wear rates on the irradiated surfaces of all three polymers increase compared with the unirradiated samples. Moreover, there is a depth gradient effect on the wear properties of both irradiated PTFE and PEEK polymers. The changes in wear rates of irradiated surfaces are consistent with the structural variations of all three polymers.

中文翻译：

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γ辐照聚四氟乙烯、聚醚醚酮和聚酰亚胺聚合物的微观结构、力学和摩擦学性能的比较研究

在本文中，三种商业聚合物（聚四氟乙烯 [PTFE]、聚醚醚酮 [PEEK] 和聚酰亚胺 [PI]）在环境空气中受到伽马射线的照射。比较研究了辐照后这三种聚合物的微观结构、力学和摩擦学性能的变化。结果表明，聚四氟乙烯的表面和内部结构都因辐照化学反应而发生降解，并且由于氧气的参与，表面分子链断裂比内部更严重。氧化降解也在 PEEK 表面起主导作用，但分子链交联在 PEEK 内部起主导作用。PI的顶层也表现出氧化辐照降解的特性，但其内部表现出优异的耐辐照性，即使在高达 20 MGy 的辐照剂量下也不会发生结构变化。所有三种聚合物的辐照表面的显微硬度和抗划伤性均降低，但辐照后仅 PTFE 的划伤损伤模式发生变化。摩擦实验表明，经辐照后，聚四氟乙烯的摩擦系数增大，而聚醚醚酮的摩擦系数减小。与未辐照样品相比，所有三种聚合物辐照表面的磨损率均增加。此外，辐照 PTFE 和 PEEK 聚合物的磨损性能都有深度梯度效应。辐照表面磨损率的变化与所有三种聚合物的结构变化一致。所有三种聚合物的辐照表面的显微硬度和抗划伤性均降低，但辐照后仅 PTFE 的划伤损伤模式发生变化。摩擦实验表明，经辐照后，聚四氟乙烯的摩擦系数增大，而聚醚醚酮的摩擦系数减小。与未辐照样品相比，所有三种聚合物辐照表面的磨损率均增加。此外，辐照 PTFE 和 PEEK 聚合物的磨损性能都有深度梯度效应。辐照表面磨损率的变化与所有三种聚合物的结构变化一致。所有三种聚合物的辐照表面的显微硬度和抗划伤性均降低，但辐照后仅 PTFE 的划伤损伤模式发生变化。摩擦实验表明，经辐照后，聚四氟乙烯的摩擦系数增大，而聚醚醚酮的摩擦系数减小。与未辐照样品相比，所有三种聚合物辐照表面的磨损率均增加。此外，辐照 PTFE 和 PEEK 聚合物的磨损性能都有深度梯度效应。辐照表面磨损率的变化与所有三种聚合物的结构变化一致。摩擦实验表明，经辐照后，聚四氟乙烯的摩擦系数增大，而聚醚醚酮的摩擦系数减小。与未辐照样品相比，所有三种聚合物辐照表面的磨损率均增加。此外，辐照 PTFE 和 PEEK 聚合物的磨损性能都有深度梯度效应。辐照表面磨损率的变化与所有三种聚合物的结构变化一致。摩擦实验表明，经辐照后，聚四氟乙烯的摩擦系数增大，而聚醚醚酮的摩擦系数减小。与未辐照样品相比，所有三种聚合物辐照表面的磨损率均增加。此外，辐照 PTFE 和 PEEK 聚合物的磨损性能都有深度梯度效应。辐照表面磨损率的变化与所有三种聚合物的结构变化一致。