UV-curable coatings have been widely used because of their environmental friendliness and low emission of volatile organic compounds (VOCs). However, the fast curing-speed of UV-curable coatings will lead to internal structural defects, which greatly restricts its application and development. In this paper, we designed and prepared a UV-curable self-healing transparent polyurethane acrylate coating based on disulfide bonds and hardened the coating by modified nano-silica. The coating shows 93 % scratch repair efficiency under UV light at 50 °C, and the coating has high hardness (4H). In addition, the coating exhibits good transparency (85 % transmittance in the visible region), which means that the coating can meet the requirements of the applications of transparency protective coating. The defect that blending inorganic particles will hinder the movement of molecular chain was overcome owing to the modified nano-silica (SiO₂-KH570) is not simply mixed with the other components but grafted onto the chain. Therefore, the addition of SiO₂-KH570 not only harden the coating, but also can reduce the glass transition temperature (T_g) of the coating that is helpful for self-healing of the coating. What's more, it is proved that the introduction of disulfide reversible bonds is helpful to eliminate internal stress of UV-curing materials by preheating process, in which the mechanical properties of the coating with disulfide bonds significantly improved (increased by at most 209 %). The present study broadens the application of UV-curable coatings, and is expected to address the problem of internal stress defects in UV-curable materials.

紫外光固化涂料因其环境友好和挥发性有机化合物（VOCs）的低排放而被广泛使用。然而，紫外光固化涂料固化速度快，会导致内部结构缺陷，极大地限制了其应用和发展。在本文中，我们设计并制备了一种基于二硫键的紫外光固化自修复透明聚氨酯丙烯酸酯涂层，并通过改性纳米二氧化硅硬化涂层。该涂层在 50°C 的紫外光下显示出 93% 的划痕修复效率，并且涂层具有高硬度 (4H)。此外，该涂层具有良好的透明度（可见光区域的透光率为85%），这意味着该涂层可以满足透明保护涂层应用的要求。₂ -KH570) 不是简单地与其他组分混合，而是接枝到链上。因此，SiO ₂ -KH570的加入不仅使涂层硬化，而且可以降低涂层的玻璃化转变温度（T _g），有利于涂层的自愈。更重要的是，证明二硫可逆键的引入有助于通过预热工艺消除UV固化材料的内应力，其中二硫键涂层的机械性能显着提高（最多提高209%）。本研究拓宽了紫外光固化涂料的应用，有望解决紫外光固化材料的内应力缺陷问题。