Abstract: Nco-terminated photosensitive polyurethane prepolymer, with its backbone chain containing hydrogen-abstraction photoinitiator and coinitiator, was prepared by the reaction of toluene diisocyanate (TDI), 4, 4'-dihydroxydiphenyl (DHBP), and N-methyldiethanolamine (MDEA ) Then, the photosensitive prepolymer was grafted onto the surface of nano-silica based on the reaction of the terminated active -NCO groups with silanols. Finally,the photosensitive modified nano-silica was dispersed into polyurethane acrylate(PUA) resin and cured by UV light to form a PUA/SiO₂ hybrid nano-structured film. FT-IR and 1H-NMR were used to confirm the structure of photosensitive nano-silica. TGA analysis, Ultraviolet spectrometer and other analyzing methods were used to investigate the properties of Uv-curing films. The results indicated that the photosensitive nano-silica, compared with the unmodified one, could significantly improve the thermal stability and mechanical properties as well as transparency of the cured coating.

Key words:  photosensitive, nano-silica, polyurethane, Uv-curing

摘要： 首先以甲苯二异氰酸酯（TDI）与夺氢型光引发剂4,4'-二羟基二苯甲酮（DHBP）以及共引发剂Ｎ－甲基二乙醇胺（MDEA）合成了主链含有光引发剂及共引发剂胺的—NCO封端的光敏性聚氨酯预聚体，后利用活性端—NCO与硅羟基反应将光敏性预聚体接枝到纳米SiO₂ 表面，最后将光敏性纳米SiO₂ 分散到聚氨酯丙烯酸酯（PUA）中，用光固化法制备了PUA／ 纳米SiO₂ 杂化膜。通过红外光谱和核磁共振氢谱证实了光敏性纳米SiO₂ 的分子结构，以热失质量法、紫外光谱仪等研究了光固化涂膜的性能。结果表明，光敏性纳米SiO₂ 可显著提高光固化涂膜的热稳定性和机械性能，并且涂膜的透明性优于添加未改性纳米SiO₂ 的涂膜。

关键词: 光敏性, 纳米SiO₂, 聚氨酯, 光固化