超高分子量聚乙烯（UHMWPE）具有优异的综合性能，是海水环境下具有重要应用前景的摩擦副材料之一。研究海水环境下UHMWPE的摩擦学行为机理、探索提高UHMWPE摩擦学性能的方法和技术，有助于提升海洋装备的工作可靠性、拓展UHMWPE的应用领域，因而具有重要的理论指导意义和工程实用价值。本论文系统地研究了UHMWPE在海水环境下的摩擦学行为及结构演变规律，揭示了其海水环境下的摩擦磨损机理。通过聚酰亚胺（PI）共混改性，制备了PI/UHMWPE共混复合材料，分析了其相态结构及分布，明确了相态结构与摩擦学性能之间的关系，并通过相态调控从而优化了摩擦学性能。开展了UHMWPE的激光表面改性技术研究，分析了激光处理对UHMWPE在海水环境下摩擦学性能的影响机制。通过对UHMWPE在海水环境下摩擦过程中的形貌及结构演变规律的研究，揭示了UHMWPE在海水环境下的摩擦磨损机理。摩擦磨损过程中，UHMWPE非晶区的分子链在应力作用下沿滑动方向拉伸并出现分子取向和结晶区片晶的滑移，同时伴随着分子构象的转变。摩擦磨损初期，UHMWPE的磨损主要表现为塑性变形导致的粘着磨损；随着时间的增加，UHMWPE磨损机理由初期的粘着磨损为主逐渐演变为粘着磨损与磨粒磨损并存的状态，UHMWPE的磨损加剧。建立了PI/UHMWPE共混材料相态结构的拉曼Mapping比值分析法，明确了相态结构与摩擦学性能对应关系，提出了相态结构及摩擦学性能调控方法，制备了适用于海水环境中应用的UHMWPE基耐磨复合材料。具有不同共混质量比的PI/UHMWPE共混材料的相结构及其分布明显不同，岛状分布和层状分布可形成弥散强化，提高承载能力，改善耐磨性。热处理可调控PI/UHMWPE共混材料的相态分布，高共混质量比的PI/UHMWPE经较低温度处理后可转变为层状分布，使其耐磨性提高。获得了不同激光处理参数下UHMWPE表面化学成分及形貌与海水环境下摩擦学性能的关系规律，揭示了激光处理对UHMWPE在海水环境下摩擦学性能的影响机制，提出了激光诱导碳化增强聚合物材料性能方法。控制UHMWPE的表面氧化程度和碳化程度可有效调控海水环境下UHMWPE的摩擦学性能。低激光功率密度下处理UHMWPE，其表面主要发生氧化反应，磨损率略有增大。高激光功率密度下处理UHMWPE，其表面主要发生碳化反应，耐磨性提高。高激光功率密度下增加扫描次数将增加氧化程度，磨损率增大。

Ultra-high molecular weight polyethylene (UHMWPE) has excellent comprehensive properties, which makes it one of the friction pair materials with important application prospects in seawater environment. Studying the tribological behavior mechanism of UHMWPE in seawater environment and exploring methods to improve the tribological performance of UHMWPE will help to improve the reliability of marine equipment and expand the application range of UHMWPE. Therefore, it has important theoretical significance and engineering practical value.In this thesis, the tribological behavior and structural evolution of UHMWPE in seawater environment were systematically studied, and the tribological mechanism of UHMWPE in seawater environment was revealed. PI/UHMWPE composites were prepared by polyimide (PI) blending modification. The structure and distribution of the pahses in PI/UHMWPE composites were analyzed, and the relationship between the phase structure and tribological properties was clarified. The tribological properties were optimized through phase control. The laser surface modification technology of UHMWPE was studied, and the influence mechanism of laser treatment on the tribological performances of UHMWPE in seawater environment was discussed.The friction and wear mechanism of UHMWPE in seawater environment was revealed by studying the morphology and structure evolution of UHMWPE in seawater environment. In the process of friction and wear, the molecular chain in the amorphous region of UHMWPE was stretched along the sliding direction under stress, and the molecular orientation and lamellar slip occurred in the crystalline region, accompanied by the transformation of molecular conformation. At the initial stage of friction and wear, the wear of UHMWPE was mainly adhesive wear caused by plastic deformation. With the increase of time, the wear mechanism of UHMWPE gradually changed from adhesive wear to the coexistence of adhesive wear and abrasive wear, and the wear of UHMWPE was intensified.A Raman Mapping ratio analysis method of phase structure of PI/UHMWPE blend material was established. The corresponding relationship between phase structure and tribological properties was clarified, and the control method of phase structure and tribological properties was proposed. A UHMWPE-based wear-resistant composite material suitable for the application in seawater environment was prepared. The phase structures and their distribution are obviously different for the PI/UHMWPE blends with different mass ratios, island and lamellar distribution can form dispersion strengthening, increase bearing capacity and improve wear resistance. The phase morphology of PI/UHMWPE blend composites could be controlled by heat treatment, the blends with high PI/UHMWPE ratio tended to form continuous layered structures, the tribological performance was obviously improved.The relationship between the chemical composition and morphology of the UHMWPE surface under different laser processing parameters and the tribological properties under seawater environment was obtained. The influence mechanism of laser treatment on the tribological properties of UHMWPE under seawater environment was revealed. A method of laser-induced carbonization to enhance the perfromance of polymer materials was proposed. Controlling the degree of surface oxidation and carbonization of UHMWPE can effectively control the tribological properties of UHMWPE in seawater environments. Oxidation occurred during laser treatment with relatively low laser power density, the wear rate increased slightly. Carbonization occurred for the laser treatment with high power density, and wear resistance increased significantly. At high laser power density, increasing the number of laser scans increased the degree of oxidation, which led to an increase in the rate.