低聚物对生物基聚对苯二甲酸丙二醇酯结晶性能的影响

逐步缩聚聚合物中通常含有一定比例的线性及环状低聚物,会影响纤维材料的成形加工、纤维性能、纺织品加工等。为探究低聚物对生物基对苯二甲酸丙二醇酯(PTT)结晶性能的影响,通过外部添加法制备得到具有不同低聚物质量分数(主要以环状二聚体为主)的生物基 PTT ,采用差示扫描量热仪分析方法对生物基PTT的结晶动力学进行研究。结果表明:低聚物的存在主要起成核剂的作用,其质量分数的增加可提高生物基 PTT的结晶速率、结晶温度及结晶度;添加低聚物质量分数为10%时,生物基 PTT的结晶速率常数由未添加的0.528提升至0.603,同时结晶温度由172.11 ℃提升至178.85 ℃。

Effect of oligomers on crystalline properties of polytrimethylene terephthalate

Step-polymerization of polymers usually contains a certain proportion of linear and circular oligomers, which will affect the forming process of fiber materials, fiber properties, textile processing and so on. To investigate the influence of oligomers on the crystallization properties of bio-based polytrimethylene terephthalate (PTT), bio-based PTT samples with varied oligomer contents (mainly comprising cyclic dimers) were prepared by adding the extracted oligomers into relatively pure PTT samples. Differential scanning calorimetry analysis was used to study the crystallization kinetics of bio-based PTT polyesters. The results show that the existence of oligomer mainly acts as nucleating agent, and the increase of its mass fraction can significantly increase the crystallization rate, the crystallization temperature and crystallinity of bio-based PTT. When the mass fraction of oligomer is 10%, the crystallization rate constant of PTT increased from 0.528 to 0.603, while the crystallization temperature increased from 172.11 ℃ to 178.85 ℃.