六氟双酚A环状聚酯二聚体的开环聚合与表征

Characterization and ring-opening polymerization of cyclic aryl ester dimer containing hexafluoroisopropylidene unit

采用界面缩聚反应,"假高稀"条件下,以六氟双酚A和邻苯二甲酰氯为单体,十六烷基三甲基溴化铵为相转移催化剂,合成了一种新型结构的芳香环状聚酯二聚体,利用MALDI-TOF-MS,NMR,FTIR,DSC等手段对其结构进行了表征.环状聚酯二聚体在阴离子引发剂苯甲酸钠的存在下,成功进行了熔融开环聚合,得到了线性高分子量的聚酯,其Tg为162.4℃,5%热失重温度为384℃.对环状聚酯熔融开环聚合过程的流变行为进行监测,结果表明,在开环聚合的引发阶段,熔融体的粘度低于10 Pa.S且增长缓慢,超过引发阶段,粘度快速增长.

Under pseudo-high dilution conditions,a kind of cyclic aryl ester dimer has been synthesized from phthaloyl dichloride and 4,4＇-（hexafluoroisopropylidene） diphenol via interfacial polycondensation reaction.Detailed structural characterization of the cyclic dimer confirmed the cyclic nature by a combination of MALDI-TOF-MS,IR and 1H NMR analyses.The cyclic dimer readily undergoes anionic ring-opening polymerization in the melt by using sodium benzoate as the initiator,producing linear,high molecular weight polyester with Tg of 162.4 ℃and excellent thermal stability.Moreover,the isothermal chemorheology of the ring-opening polymerization of cyclic dimer is also investigated.The results show that the shear viscosity of the molten reactive mixture increases slowly and is lower than 10 Pa·S at a constant shear rate of 0.05 S-1 in the initial stage of ring-opening polymerization and the viscosity increases dramatically after the initial stage.