Design and synthesis of liquid crystal copolyesters with high-frequency low dielectric loss and inherent flame retardancy  

作　　者：Shi-Yu Zhang Teng Fu Yue Gong De-Ming Guo Xiu-Li Wang Yu-Zhong Wang 

机构地区：[1]State Key Laboratory of Polymer Materials Engineering,The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials,National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan),College of Chemistry,Sichuan University,Chengdu 610064,China

出　　处：《Chinese Chemical Letters》2023年第5期621-625,共5页中国化学快报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51991351 and 51991350);the Fundamental Research Funds for the Central Universities;the 111 Project(No.B20001);the Sichuan Science and Technology Program(No.2020YFH0016)。

摘　　要：Ultra-low dielectric loss(Df)and low dielectric constant(Dk)materials are urgently required in highspeed and large-capacity transmission,in which the wholly aromatic liquid crystal polymer(LCP)has gained attention due to its excellent dielectric properties.However,the relationship between molecular structure and dielectric properties is still not clear.In this study,two copolyesters containing phenyl or naphthyl structures are synthesized,as well as the effects of benzene and naphthalene mesogens on dielectric properties are investigated.The synthesized copolyesters containing naphthalene structure have good comprehensive properties with high thermal stability(T_(5%)=479℃ and T_g=195-216℃),inherent flame retardance(LOI=33.0-35.0 and UL-94 V-0 level at 0.8 mm),low Dk(2.9-3.0@10 GHz)and low Df(0.0027-0.0047@10 GHz).Naphthalene mesogen can reduce the dielectric loss more significantly than benzene at high frequency by reducing the density and mobility of polarizable groups,which leads to the effectively limited dipole polarization in copolyesters.Consequently,we proposed a new strategy for designing low Dk and low Df materials.

关 键 词：Liquid crystal polymer Low dielectric loss Low dielectric constant Naphthalene structure Flame retardant 

分 类 号：TQ317[化学工程—高聚物工业]