退火对热致型液晶共聚酯吹塑薄膜结晶和力学性能的影响  

Study on Crystalline and Mechanical Properties of Thermotropic Liquid Crystal Polymer Films by Annealing

作　　者：黎智源 唐大航 谢嘉宜 徐睿杰[1] 雷彩红[1] LI Zhi-yuan;TANG Da-hang;XIE Jia-yi;XU Rui-jie;LEI Cai-hong(School of Materials and Energy,Guangdong University of Technology,Guangzhou 510006,China;Kingfa Science and Technology Co.,Ltd.,Guangzhou 510663,China)

机构地区：[1]广东工业大学材料与能源学院,广州510006 [2]金发科技股份有限公司,广州510663

出　　处：《高分子通报》2024年第7期917-923,共7页Polymer Bulletin

摘　　要：液晶聚合物(LCP)吹塑薄膜制备过程中由于LCP棒状大分子结构的存在,薄膜沿流动方向(MD)易产生高度取向,引起垂直流动方向(TD)力学性能差而易被撕裂,往往需要通过退火处理调控两个方向力学性能的差异。本文探讨了退火条件对由1,4-羟基苯甲酸(HBA)和6-羟基-2-萘甲酸(HNA)为单体共聚而成的热致性液晶聚合物(TLCP)吹塑薄膜的结晶、力学及微观结构的影响。结果表明:提高退火温度,结晶度表现为先增加后减少;长时间的高温退火可明显降低LCP薄膜分子链的取向度,使其转变为近似各向同性;此外,流变和凝胶率测试结果表明结晶度的变化与LCP在退火过程中发生交联反应相关;而结晶与交联的变化影响了薄膜两个方向的力学性能。During the preparation of blow-molded liquid crystal polymer(LCP)films,the existence of rod-like macromolecular structure in LCP results in the films to be highly oriented along the extrusion direction(MD),leading to poor mechanical properties and making the film prone to tearing along the extrusion direction(TD).It is often necessary to regulate the difference of mechanical properties along the two directions by annealing.In this work,the blow-molded films of thermotropic liquid crystal polymer(TLCP)copolymerized with p-hydroxybenzoic acid(HBA)and 2-hydroxy-6-naphthoic acid(HNA)as monomers were annealed,and the effects of annealing conditions on the crystalline,mechanical and microstructural properties were investigated.The results show that increasing the annealing temperature,the crystallinity exhibits a tendency of increase then decrease,and that prolonged high-temperature annealing could significantly reduce the orientation of the molecular chains in the LCP films,which transforms them into approximate isotropy.In addition,the change of crystallinity may be related to the cross-linking reaction during annealing,proven by the rheological and gel fraction results.The mechanical properties of LCP films along MD and TD are related to the crystallinity and cross-linking during annealing.

关 键 词：退火 液晶聚合物 结晶度 交联 取向度 

分 类 号：TQ320.721[化学工程—合成树脂塑料工业]