PET环状低聚物在高黏熔体中的开环聚合反应规律

Reaction law of ring-opening polymerization of PET cyclic oligomer in high-viscosity melt

在熔融缩聚制备聚对苯二甲酸乙二醇酯(PET)的过程中会生成环状低聚物对苯二甲酸乙二醇酯(COET),研究COET在高黏体系中的开环聚合规律具有一定的现实意义。通过悬浮法制备COET,然后将COET共混到高黏反应载体聚苯乙烯(PS)中,经聚合反应后得到PS/PET共混物。研究COET与PS开环聚合形成PS/PET共混物的开环聚合反应规律,分析PS/PET共混物的热性能及PS与PET两相间的相容性。结果表明:采用悬浮法制备得到的COET以环状三聚体为主,熔点高达307℃;高黏体系显著降低了COET开环聚合温度,开环聚合产物的特性黏度与反应温度和反应时间呈正相关;COET在PS中原位开环聚合形成的PS/PET共混物为两相不相容体系,分散相尺寸远小于PET直接共混形成的PS/PET共混物。该研究可为解决聚酯中存在的低聚物问题和制备高性能的共混材料提供参考。

Due to the generation of cyclic oligomers(COET) as the result of the fabrication of polyethylene terephthalate(PET) by melt polycondensation, studying the ring-opening polymerization law of COET in high-viscosity systems is of certain practical meaning. In this paper, COET was fabricated by the suspension method, and then the COET was blended into polystyrene(PS), and the PS/PET blend was obtained after polymerization. The ring-opening polymerization of PS/PET blend formed by the ring-opening polymerization of COET and PS was studied, and its thermal properties and the compatibility between PS and PET were analyzed. The results show that the COET fabricated by the suspension method is mainly cyclic trimer, with a melting point of up to 307 ℃, and the high-viscosity system significantly reduces the COET ring-opening polymerization temperature, the intrinsic viscosity of the ring-opening polymerization product is positively correlated with the reaction temperature and reaction time;the PS/PET blend generated by in-situ ring-opening polymerization of COET in PS is a two-phase incompatible system, and the size of the dispersed phase is much smaller than that of the PS/PET blend directly generated by PET. This research is expected to provide reference for solving the problem of oligomers in polyester and fabricating high-performance blended materials.