Zhong Xiao, Ruan Kunpeng, Gu Junwei
Research & Development Institute of Northwestern Polytechnical University, Shenzhen, Guangdong 518057, China.
Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
Research (Wash D C). 2022 Jul 16;2022:9805686. doi: 10.34133/2022/9805686. eCollection 2022.
Enhancing thermal conductivity coefficient () of liquid crystal polyesters would further widen their application in electronics and electricals. In this work, a kind of biphenyl-based dihydroxy monomer is synthesized using 4, 4'-biphenyl (BP) and triethylene glycol (TEG) as raw material, which further reacts with three different dicarboxylic acids (succinic acid, p-phenylenediacetic acid, and terephthalic acid, respectively) by melt polycondensation to prepare intrinsically highly thermally conductive poly 4', 4"'-[1, 2-ethanediyl-bis(oxy-2, 1-ethanediyloxy)]-bis(p-hydroxybiphenyl) succinate (PEOS), poly 4', 4"'-[1, 2-ethanediyl-bis(oxy-2, 1-ethanediyloxy)]-bis(p-hydroxybiphenyl) p-phenyldiacetate (PEOP) and poly 4', 4"'-[1, 2-ethanediyl-bis(oxy-2, 1-ethanediyloxy)]-bis(p-hydroxybiphenyl) terephthalate (PEOT), collectively called biphenyl-based liquid crystal polyesters (B-LCPE). The results show that B-LCPE possess the desired molecular structure, exhibit smectic phase in liquid crystal range and semicrystalline polymers at room temperature, and possess excellent intrinsic thermal conductivities, thermal stabilities, and mechanical properties. of PEOT is 0.51 W/(m·K), significantly exceeds that of polyethylene terephthalate (0.15 W/(m·K)) which has similar molecular structure with PEOT, and also higher than that of PEOS (0.32 W/(m·K)) and PEOP (0.38 W/(m·K)). The corresponding heat resistance index ( ), elasticity modulus, and hardness of PEOT are 174.6°C, 3.6 GPa, and 154.5 MPa, respectively, and also higher than those of PEOS (162.2°C, 1.8 GPa, and 83.4 MPa) and PEOP (171.8°C, 2.3 GPa, and 149.6 MPa).
提高液晶聚酯的热导率系数（）将进一步拓宽其在电子电器领域的应用。在本工作中，以4,4'-联苯（BP）和三甘醇（TEG）为原料合成了一种联苯二羟基单体，该单体再分别与三种不同的二元羧酸（琥珀酸、对苯二甲酸二乙酸酯和对苯二甲酸）通过熔融缩聚反应制备出具有本征高导热性的聚4',4"'-[1,2-乙二基-双（氧基-2,1-乙二氧基）]-双（对羟基联苯）琥珀酸酯（PEOS）、聚4',4"'-[1,2-乙二基-双（氧基-2,1-乙二氧基）]-双（对羟基联苯）对苯二甲酸二乙酸酯（PEOP）和聚4',4"'-[1,2-乙二基-双（氧基-2,1-乙二氧基）]-双（对羟基联苯）对苯二甲酸酯（PEOT），统称为联苯型液晶聚酯（B-LCPE）。结果表明，B-LCPE具有理想的分子结构，在液晶范围内呈现近晶相，在室温下为半结晶聚合物，并且具有优异的本征热导率、热稳定性和机械性能。PEOT的为0.51W/（m·K），显著超过了与PEOT分子结构相似的聚对苯二甲酸乙二酯（0.15W/（m·K）），也高于PEOS（0.32W/（m·K））和PEOP（0.38W/（m·K））。PEOT相应的耐热指数（）、弹性模量和硬度分别为174.6°C、3.6GPa和154.5MPa，也高于PEOS（162.2°C、1.8GPa和83.4MPa）和PEOP（171.8°C、2.3GPa和149.6MPa）。
