基于聚氨酯壁材的单/双壳微胶囊光致变色性能及机制

采用原位聚合法分别制备了聚氨酯微胶囊和以聚氨酯为内壳,壳聚糖为外壳的双壳光致变色微胶囊。所制备的聚氨酯-壳聚糖双壳光致变色微胶囊和聚氨酯微胶囊与未包覆的偶氮光致变色化合物相比,表现出增强对偶氮光致变色化合物的密封性和通过双壳结构改变偶氮光致变色化合物所接受的光辐照强度的优势。在变色过程中,与偶氮化合物溶液相比,聚氨酯微胶囊和聚氨酯-壳聚糖微胶囊整理液使达到变色稳态的时间分别减慢了1.6 s和4.8 s。在褪色过程中,偶氮光致变色化合物溶液褪色达到稳态需要20 s;聚氨酯单壳光致变色微胶囊整理液的速度减缓至它的36%;而聚氨酯-壳聚糖双壳光致变色微胶囊整理液的速度减缓至它的40%。

Photochromic performance and optics mechanism of single/double shell microcapsules

Polyurethane photochromic microcapsules and double shell photochromic microcapsules with polyurethane as inner wall material and chitosan as outer wall material have been prepared respectively using in situ polymerization. Comparing with unencapsulated azo photochromic compound, the prepared polyurethane photochromic microcapsules and polyurethane-chitosan double shell photochromic microcapsules showed advantages in the improved leakproofness of the applied photochromic compound and the irradiation intensity the photochromic compound accepted changed by double shell structure. It can be observed that, during coloration process, comparing with the time azo photochromic compound solution needed to reach the steady state during coloration process, polyurethane photochromic microcapsules and polyurethane-chitosan double shell microcapsules suspensions delayed the coloration process for 1.6 s and 4.8 s respectively. Moreover, during decoloration process, azo compound solution lost the steady state and decreased to the minimum absorbance at 20 s, and for polyurethane microcapsules and polyurethane-chitosan double shell microcapsules suspensions, it slowed down to 36% and 40%, respectively.