光响应型主链偶氮苯液晶聚氨酯的制备及表征  

Preparation and characterization of photoresponsive main-chain azobenzene liquid crystal polyurethanes

作　　者：陈有慧 陈权[1] 朱鹏 徐锐[1] Chen Youhui;Chen Quan;Zhu Peng;Xu Rui(School of Chemistry&Chemical Engineering,Henan University of Science and Technology,Luoyang 471023)

机构地区：[1]河南科技大学化学化工学院,洛阳471023

出　　处：《化工新型材料》2024年第10期96-100,107,共6页New Chemical Materials

摘　　要：通过硝基热还原法、Williamson醚合成法、Steglich酯化反应合成了3种偶氮苯液晶基元单体(LC),在氮气气氛下通过与1,6-己二异氰酸酯(HDI)反应,并以甲醇封端制备出3种主链型偶氮苯液晶聚氨酯(LCPU),采用核磁共振氢谱仪(1H-NMR)、傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TG)、差示扫描量热仪(DSC)、热台显微镜(POM)、紫外-可见分光光度计(UV-Vis)对LC及LCPU进行了表征。^(1)H-NMR、FT-IR对LC及LCPU分子结构的表征结果符合预期;TG、DSC、POM分析结果表明LCPU热稳定性良好,LC和LCPU具有良好的液晶性。与4,4′-二氧己醇偶氮苯(记作LC_(1))和4,4′-二对氧己醇苯甲酸酯偶氮苯(记作LC_(3))相比,具有不对称结构的4-氧己醇-4′-对氧己醇苯甲酸酯偶氮苯(记作LC_(2))具有更高的玻璃化转变温度,偶氮苯液晶聚氨酯LCPU_(2)具有较低的玻璃化转变温度和相对较宽的液晶相区间。UV-Vis分析结果表明LC及LCPU在波长365nm紫外光照射下出现了典型的顺反异构转化,具有良好的光响应性。Three kinds of azobenzene liquid crystal monomers(LC)were synthesized by nitrothermal reduction,Williamson ether synthesis and Steglich esterification.Three main-chain azobenzene liquid crystal polyurethanes(LCPU)were prepared by reacting with 1,6-hexyl diisocyanate(HDI)under nitrogen atmosphere and end-capped with methanol.The LC and LCPU were characterized by nuclear magnetic resonance hydrogen spectrometer(^(1)H-NMR),Fourier transform infrared spectrometer(FT-IR),thermogravimetric analyzer(TG),differential scanning calorimeter(DSC),hot table microscope(POM)and UV-Vis.The molecular structures of LC and LCPU were characterized by 1H-NMR and FT-IR.The results of TG,DSC and POM analysis showed that LCPU had good thermal stability,and LC and LCPU had good liquid crystalline properties.Compared with 4,4′-dioxahexanol azobenzene(labeled as LC_(1))and 4,4′-dioxahexanol benzoate azobenzene(labeled as LC_(3)),4-oxahexanol,4′-dioxahexanol benzoate azobenzene(labeled as LC_(2))with asymmetric structure had higher glass transition temperature.Azobenzene liquid crystal polyurethane LCPU_(2) had a lower glass transition temperature and a relatively wide liquid crystal phase interval.The results of UV-Vis analysis indicated that LC and LCPU exhibited typical cis-trans isomerization under the irradiation of 365nm ultraviolet light,demonstrating good photoresponsiveness.

关 键 词：偶氮苯 液晶基元 主链型偶氮苯液晶聚氨酯 

分 类 号：O631.24[理学—高分子化学]