Zhang Yuhua, Zhang Xi, Yan Yurong, Chen Zhonghua
School of Material Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Polymers (Basel). 2021 Sep 9;13(18):3049. doi: 10.3390/polym13183049.
Photochromic materials are interesting materials because of their color-changing property under UV light and visible light irradiation. However, they are vulnerable to many factors, such as pH oxygen, ion, solvent, etc. because of the unsaturated bonds existing on the photochromic molecular. Microencapsulation of the photochromic materials can separate them from the surroundings. Here, photochromic microcapsules using 3,3-Diphenyl-3H-naphtho[2,1-b] pyran (NP)/solution as core and polyurea as shell via interfacial polymerization were prepared, and bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate (HALS 770) was used as photostabilizer. Fourier transform infrared spectroscopy (FTIR), a laser particle size analyzer, a scanning electron microscope (SEM), a thermogravimetric analyzer and an ultraviolet-visible spectrophotometer were used for characterization. The results showed that the microcapsules had a uniform particle size of about 0.56 μm when the percentage of the oil phase (core) in the emulsion was less than 15%, the addition amount of the emulsifier was 0.4%, and the stirring rate was 1800 r/min. The microcapsules showed better performance in thermal stability when the core/shell ratio was 1:1. The photostabilizer had little impact on the color-changing property of the microcapsule, but it could protect the microcapsules from UV light radiation aging.
光致变色材料因其在紫外光和可见光照射下的变色特性而成为有趣的材料。然而，由于光致变色分子上存在不饱和键，它们易受许多因素影响，如pH值、氧气、离子、溶剂等。光致变色材料的微胶囊化可以使其与周围环境隔离。在此，通过界面聚合法制备了以3,3 - 二苯基 - 3H - 萘并[2,1 - b]吡喃（NP）/溶液为芯、聚脲为壳的光致变色微胶囊，并使用双（2,2,6,6 - 四甲基 - 4 - 哌啶基）癸二酸酯（HALS 770）作为光稳定剂。采用傅里叶变换红外光谱（FTIR）、激光粒度分析仪、扫描电子显微镜（SEM）、热重分析仪和紫外 - 可见分光光度计进行表征。结果表明，当乳液中油相（芯）的百分比小于15%、乳化剂添加量为0.4%且搅拌速率为1800 r/min时，微胶囊的粒径均匀，约为0.56μm。当芯/壳比为1:1时，微胶囊表现出更好的热稳定性。光稳定剂对微胶囊的变色性能影响较小，但它可以保护微胶囊免受紫外光辐射老化。
