1,8-辛二酸改性热致液晶共聚酯的制备及其性能  

Synthesis and Properties of Thermotropic Liquid Crystal Copolyesters Modified by 1,8-Suberic Acid

作　　者：吕荣盛 高欣逸 蒋杰 赵世成[2] 赵玲[1,2] 奚桢浩[1,2] LYU Rongsheng;GAO Xinyi;JIANG Jie;ZHAO Shicheng;ZHAO Ling;XI Zhenhao(State-Key Laboratory of Chemical Engineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China;Shanghai Key Laboratory of Multiphase Materials Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化工学院化学工程联合国家重点实验室,上海200237 [2]华东理工大学上海市多相结构材料化学工程重点实验室,上海200237

出　　处：《功能高分子学报》2023年第1期69-76,共8页Journal of Functional Polymers

基　　金：国家自然科学基金面上项目(21878256);上海市优秀学术/技术带头人计划资助(21XD1433000)。

摘　　要：以对羟基苯甲酸、对苯二甲酸和对苯二酚为共聚单体,经乙酰化和熔融缩聚两步法合成三元热致液晶共聚酯。引入长链脂肪族化合物1,8-辛二酸作为改性单体,按不同比例代替对苯二甲酸,制备了一系列含柔性链段的新型四元热致液晶共聚酯。通过傅里叶红外光谱(FT-IR)和核磁共振碳谱(13C-NMR)对共聚酯结构进行表征,采用差示扫描量热(DSC)和热失重分析(TGA)表征其热性能,采用偏光显微镜(POM)和X射线衍射(XRD)分析其液晶性能。研究表明,三元液晶共聚酯熔点达407℃,热稳定性优异。随着1,8-辛二酸含量增加,四元共聚酯熔点显著降至214℃,热稳定性较好,最大热分解温度达到428℃。该系列共聚酯显示了典型的向列型液晶织态结构。1,8-辛二酸的引入显著改善了液晶共聚酯的可加工性。Thermotropic liquid crystal copolyesters(TLCPs)with high melting point were synthesized by acetylation and melt polycondensation using p-hydroxybenzoic acid(HBA),terephthalic acid(PTA),and hydroquinone(HQ)as monomers.HBA and HQ were converted into 4-acetyloxybenzoic acid(ABA)and 1,4-diacetoxybenzoic(AHQ)respectively by acetylation to improve the reactivity.Zinc acetate was selected as the catalyst,and the mole ratio of monomers was n(ABA)∶n(PTA)∶n(AHQ)=60∶20∶20.The ternary copolyester shows excellent thermal stability and high melting point of 407℃.Furthermore,a series of new TLCPs(HBA/PTA/SuA/HQ)containing flexible segments were synthesized by incorporating the long-chain aliphatic 1,8-suberic acid(1,8-SuA),partially replacing PTA.The structure of the modified copolyesters were characterized by Fourier transform infrared spectrometer(FT-IR)and carbon-13 nuclear magnetic resonance(13C-NMR).The thermal properties and the liquid crystal texture of the copolyesters were analyzed using differential scanning calorimetry(DSC),thermal gravimetric analyzer(TGA),polarized optical microscope(POM)and X-ray diffraction(XRD).The results show that the melting point of the HBA/PTA/SuA/HQ copolyester decreases from 407℃to 214℃with the increasing of the 1,8-SuA content,but the crystallinity increases from 25.2%to 32.2%.The synthesized TLCPs show good thermal stability with the maximum decomposition temperature over 428℃.The decomposition temperature of the copolyesters decreases with the 1,8-SuA increases accordingly,and the char yield is between 22.1%and 31.3%,slightly lower than the initial ternary copolyester.All the synthesized copolyesters exhibit the similar textures of nematic liquid crystals.The results indicate that the combination property of the new copolyesters is little influenced by the introduction of long-chain aliphatic 1,8-SuA but the processability can be significantly improved.

关 键 词：热致液晶共聚酯 1 8-辛二酸 向列型液晶 熔点 热稳定性 

分 类 号：TQ322.3[化学工程—合成树脂塑料工业]