水润滑尾轴承在低速和重载工况条件下容易产生严重磨损与表面微缺陷。通过使用自修复微胶囊作为填料, 赋予复合材料内部微缺陷的自修复能力, 可以改善超高分子量聚乙烯(UHMWPE)水润滑尾轴承的使役性能。联用Pickering法与原位聚合法来制备含有活性异氟尔酮二异氰酸酯(IPDI)的自修复微胶囊, 以硅烷交联改性UHMWPE来制备含自修复微胶囊的UHMWPE复合材料, 探究不同的自修复微胶囊添加量对复合材料的机械性能、摩擦学性能及自修复性能的影响。测试结果表明：微胶囊的加入降低了复合材料的机械性能和摩擦学性能, 微胶囊含量越高这2种性能下降越多。与此同时随着微胶囊含量的提升, 复合材料自修复性能越好。综合考虑自修复微胶囊含量对复合材料的这3种性能的影响, 当微胶囊含量达到10%时复合材料的综合性能达到最佳, 为设计优异使役性能的新型水润滑轴承材料提供了参考。

Objective: The water-lubricated tail bearing is a critical component of a ship's propulsion system. Its stability and reliability significantly affect the safety of ship operations. Under low-speed, heavy-load conditions, forming a stable hydrodynamic lubrication water film becomes challenging, often resulting in poor lubrication. This can cause micro-defects on the composite material's surface. To address this, microcapsules containing diisocyanate are incorporated into the composite material, enabling it to autonomously repair such micro-defects. This study explores how the mass fraction of self-healing microcapsules affects the self-repairing ability, mechanical properties, and tribological performance while also analyzing the underlying mechanisms. Methods: Self-healing microcapsules containing active IPDI self-healing agents were prepared using a combination of Pickering emulsion and in situ polymerization methods. Composite materials infused with these microcapsules were then fabricated using hot pressing. The mechanical properties of the composites were analyzed using differential scanning calorimetry, dynamic mechanical analysis, and mechanical performance tests. Scratch tests were employed to assess the self-repairing capabilities of the composites, while an Rtec tribometer was used to evaluate their tribological properties. The worn surfaces were examined using a scanning electron microscope and laser confocal microscopy. Results: The addition of self-healing microcapsules negatively impacted the mechanical properties of the composite materials as the microcapsule mass fraction increased. Specifically, the crystallinity of the composites containing 5%, 10%, and 15% microcapsules decreased to 9.87%, 12.37%, and 14.50%, respectively, compared to UHMWPE-1. The storage modulus decreased by 28.33%, 31.8%, and 38.61% while bending strength decreased by 13.56%, 18.29%, and 26.58%. When the microcapsule mass fraction exceeded 10%, the decline in mechanical properties accelerated. This was attributed to poor microcapsule dispersion of microcapsules within the matrix material content, which reduced rigidity and elasticity. Regarding self-repairing performance, the self-healing efficiencies of UHMWPE-I5, UHMWPE-I10, and UHMWPE-I15 composites reached 16%, 33%, and 78%, respectively. However, the tribological properties degraded under low-speed, heavy-load working conditions (Condition 2). Compared to UHMWPE-1, the average friction coefficients of UHMWPE-I5, UHMWPE-I10, and UHMWPE-I15 increased by 22.68%, 49.03%, and 101.72%, while wear volumes grew by 66.88%, 67.57%, and 73.42%. Additionally, higher microcapsule content led to more pronounced adhesive wear on the composite surface. Similarly to the mechanical properties, the decline in tribological properties intensified when the microcapsule mass fraction exceeded 10%. Conclusions: This study analyzed the impact of self-healing microcapsules on composite material performance, focusing on mechanical properties, tribological behavior, and self-repairing ability. As the microcapsule mass fraction increased, the self-repairing performance improved significantly but at the expense of reduced mechanical and tribological properties. The optimal microcapsule mass fraction was identified as 10%, striking a balance between maintaining mechanical and tribological integrity and achieving effective self-repairing capabilities. These findings lay a solid experimental foundation for optimizing self-healing water-lubricated composite materials.