在液晶场中光交联反应的研究

Photocrosslinking Reaction Of Photosensitive Polymer In Liquid Crystal Field

研究了具有肉桂酸酯基的侧链型液晶高分子的光化学行为。研究表明:如以20分钟光照交联转化率为比较标准,则形成液晶相的液晶高分子的光交联转化率要高于未形成液晶相同种高分子的光交联转化率。当光照温度低于液晶高分子各向同性温度(T-i)时,温度对光交联转化率的影响不显著。这反映了由于液晶高分子中mesogen基(液晶基元)的聚集和有序排列,形成了具有微区结构的物理交联型大分子,这一结构影响了大分子链中肉桂酸酯侧基的聚集状态,从而使真的光交联反应性质不同于无定形的同类高聚物。

In this work, the behavior of photocrosslinking reaction of side-chain liquid crystal copolymer P(MPAEB-co-VBC) and P(MPAHB-co-VBC), which were synthe-sised through reaction between P(MPAEB-co-CMS) or P(MPAHB-co-CMS) and potassium cinnamate, was investigated. An photocrosslinking conversion of photosensitive liquid crystal copolymer is increased with radiation times. At room temperature the conversion of quenched membrane is higher than unquenched one for all liquid crystal copolymer, but did not change for VBC homopolymer. When the temperature of sample is changed from room temperature ( but for quenched one ) to 100C , there is no clear difference in photocrosslinking conversion for P(MPAEB-co-VBC) (85/ 15) and P(MPAHB-co-VBC) (857 15). These observations show that because of ordered arrangement of mesogen groups in liquid crystal copolymer, physical crosslinking macromolecule, which have domain structure, were formed. The domain structures can influence aggregational conditions of cinnamate groups in the macromolecular chains and result in different characteristics from amorphose same one.