分子结构对乙基氰乙基纤维素/丙烯酸胆甾型液晶性的影响  

Influence of Molecular Structure on the Cholesteric Phase of Ethyl-Cyanoethyl Cellulose/Acrylic Acid Solutions

作　　者：张冠琦[1] 周雪松[1,2] 李静[1] 黄勇[1,2] 

机构地区：[1]中国科学院广州化学研究所纤维素化学开放研究实验室 [2]中国科学院化学研究所北京100080

出　　处：《纤维素科学与技术》2001年第3期1-10,共10页Journal of Cellulose Science and Technology

基　　金：国家基础性重大关键项目 (攀登计划 ) -高分子凝聚态基本物理问题研究;国家杰出人才基金资助项目

摘　　要：乙基氰乙基纤维素 [(E -CE)C]可溶于丙烯酸 (AA)形成胆甾型溶致液晶体系 ,液晶溶液的临界浓度 (C1 )与 (E -CE)C的分子量 (MW)有关 ,MW 越高 ,C1 越低。同时 ,C1 还受 (E -CE)C氰乙基取代度 (DS)的影响 ,DS越大 ,C1 越低。相同DS时 ,胆甾相的螺距 (P)随MW 增加而增大 ;在MW 相近时 ,随DS的升高 ,P先减小 ,后增大 ,在DS 0 .2～ 0 .3之间有最小值。P随 (E -CE)C/AA溶液浓度的增大而降低。 (E -CE)C/AA溶液中的AA快速聚合后 ,体系胆甾相选择性反射光的能力和选择性均有所降低 ,并且最大选择性反射光的波长 (λmax)蓝移。聚合前溶液的浓度越小 。Ethyl-cyanoethyl cellulose can form cholesteric liquid crystals in acrylic acid (AA). The liquid crystalline behavior is related to the (E-CE)C molecular structure . The critical concentration C 1, at which the cholesteric phase appears, decreases with increasing both (E-CE)C molecular weight and the degree of substitution for cyanoethyl. The pitch is dependent on the (E-CE)C molecular weight and the degree of substitution for cyanoethyl . The cholesteric pitch increases with increasing (E-CE)C molecular weight when the degree of substitution for cyanoethyl is the same and first decreases and then, increases with increasing the degree of substitution for cyanoethyl when the (E-CE)C molecular weight is the same. There is the minimum value of the pitch when the degree of substitution for cyanoethyl is about 0.25. The pitch of cholesteric phase decreases with increasing the (E-CE)C concentration and the changing tendency is not influenced by the molecular weight of (E-CE)C. After the polymerization of the AA in the (E-CE)C/AA liquid crystalline solutions, the wavelength of the selective reflection of the cholesteric phase shifts to shorter wavelength direction and the selectivity and the intensity of the reflection are also decreased. The shift of the selective reflection wavelength of the cholesteric phase decreases with increasing the concentration of the (E-CE)C/AA cholesteric liquid crystalline solution. The maintenance of the cholesteric structure is independent on the (E-CE)C molecular weight during the polymerization of the AA in the (E-CE)C/AA liquid crystalline solutions.

关 键 词：乙基氰乙基纤维素 胆甾型液晶 分子量 取代度 聚合 复合物 分子结构 丙烯酸 

分 类 号：O631.1[理学—高分子化学] TQ352.121[理学—化学]