论文部分内容阅读
采用固相聚合的方法合成了一系列PET-季戊四醇共聚酯,测试了共聚酯的特性黏度随固相缩聚时间的变化,并且用差示扫描量热法研究了该体系的非等温结晶过程,采用偏光显微镜观察了其结晶形态。结果表明:季戊四醇的含量越高,PET-共聚酯的特性黏度出现先下降后上升趋势、形成支化结构的时间越早。在固相聚合反应初期,共聚酯的结晶温度上升,半结晶时间减少;但随着固相聚合时间的延长,共聚酯的结晶温度下降,形成的晶粒变小;而且,共聚酯具有二次结晶现象。
A series of PET-pentaerythritol copolyesters were synthesized by solid-state polymerization. The intrinsic viscosities of the copolyesters were measured with the solid-phase polycondensation time, and the non-isothermal crystallization process of the system was studied by differential scanning calorimetry , The polarizing microscope was used to observe its crystalline morphology. The results showed that the higher the content of pentaerythritol, the lower the intrinsic viscosity of PET-copolyester tends to increase, and the earlier the branching structure is formed. In the initial stage of the solid-phase polymerization, the crystallization temperature of the copolyester increases and the crystallization time decreases. However, the crystallization temperature of the copolyester decreases with the increase of the solid-state polymerization time, and the crystal grains become smaller. Moreover, the copolyesters With secondary crystallization phenomenon.