摘要
以4-(6-丙烯酰氧基己氧基)苯甲酸-4-羟基-4-(甲氧基)酯和4-(6-丙烯酰氧基己氧基)苯甲酸-7-羟基香豆素酯为单体合成了一种共聚物，并研究了影响此液晶高分子光学各向异性的因素。通过动态紫外光谱考查了曝光量、曝光温度及热处理温度对液晶聚合物膜层光化学性能及取向性能的影响。结果表明：随着曝光量的增加，聚合物薄膜光化学反应程度逐渐增大，且在曝光量为3.7J/cm2时，光化学反应程度达到饱和。随着曝光温度的增加，分子发生了光重排反应，而光二聚反应程度降低。在曝光量为3.7J/cm2及曝光温度25℃时，聚合物薄膜随着热处理温度的升高，液晶分子的取向方向呈现一定的周期变化，但产生的最大各向异性值基本保持不变。
Abstract
In this paper, a liquid crystal copolymer was prepared by 4-( 6-acryloyloxy-hexyloxy ) benzoic acid-4-hydroxyl-4-( methoxyl ) ester and 4-( 6-acryloyloxy-hexyloxy ) benzoic acid-7-hydroxyl, and it was used to study the factors which affected optical anisotropy of liquid crystal polymer with photosensitive groups. The photoreaction behaviors and orientation performance of the liquid crystal polymer film were investigated with linearly polarized ultraviolet light ( LPUV ) under different exposure dose, exposure temperature and annealing temperature. The results showed that the degree of photoreaction of the film was enhanced with increasing of exposure energy. When the exposure energy reached 3. 7J/cm2 , the maximum degree of photoreaction was achieved. Under higher exposure temperatures, the Photo-Fries rearrangement occurred, whereas the photo - induced dimerization reaction was reduced. At last, under the room temperature and exposure dose of 3. 7J/cm2 , the optical anisotropy of the liquid crystal film exhibited periodic variation as the annealing temperature was rising. However, the maximum anisotropy value remained nearly unchanged.
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