水性光致变色聚氨酯的制备及其性能研究

Study on Preparation and Photochromic Properties of Waterborne Polyurethane

采用2种不同方式将螺吡喃与聚氨酯相结合制备水性光致变色聚氨酯,一种方式是将合成的水性聚氨酯分散液与螺吡喃的乙醇溶液进行物理共混,得到共混光致变色聚氨酯乳液(BPPU);另一种方式是将有机光致变色螺吡喃分子作为终端引入聚氨酯预聚体中,水分散得到水性光致变色聚氨酯乳液(CPPU)。利用紫外-可见分光光度计分别研究了BPPU乳液、CPPU乳液及其成膜的光致变色性能,并利用SEM观察了共混、共聚薄膜的微观结构。结果发现:BPPU乳液不稳定,涂膜中螺吡喃成分容易聚集;CPPU乳液和膜均具有良好的光致变色性能,涂膜中螺吡喃组分分布较均匀。

Waterborne photochromic polyurethanes were prepared by two different ways with spiropyran and polyurethane. One way was to blend spiropyran and aqueous polyurethane dispersions to obtain photochromic polyurethane emulsion （BPPU）. Another way was to graft the photochromic spiropyran moleeules into polyurethane prepolymer and then disperse it in water to form photochromic waterborne polyurethane （CPPU）. The photochromic properties of BPPU emulsion, CPPU emulsion and their films were studied. The microstrncture of BPPU and CPPU film was investigated by SEM. The results showed that the BPPU emulsion was not stable and the spiropyran compounds inclined to agglomerate in the film. Whereas, the CPPU emulsion and its film had good photochromic properties and the spiropyran was well dispersed in the film.