PET/PEN扩链反应共混的研究——结晶与熔融行为

Study on PET/PEN Chain Extension Reactive Blending──Effect on Crystallization and Melting Behavior

用差示扫描量热法 (DSC)研究了PET/PEN扩链反应性共混物体系的热性能 ,对共混比例、温度和时间对热性能的影响进行了讨论 ,并进一步考察了序列结构变化和热性能的关系。结果表明 ,不同比例的PET/PEN都呈现出一个玻璃化温度 ,即PET、PEN在无定形态是相混溶的 ;冷结晶温度和熔融温度与共混比例、共混时间、温度等因素密切有关。PET/PEN5 0 /5 0即使共混短时间 ,亦不结晶。其他比例共混物随共混时间的增加 ,冷结晶温度升高 ,熔点下降 ,与序列长度变化有关。当序列长度小于 7时 ,冷结晶峰消失。当酯交换度大于 30 %时熔融峰消失。

The effects of blending condition,compositions,time on the thermal behavior of PET/PEN reactive blends were studied by DSC. We further discussed the relationship between the number-average sequence length and thermal behavior. PET/PEN at various compositions all show a single class transition temperature T g,Which means PET and PEN were miscible in amorphous phase. The blending composition,temperature and time have a dramatic effect on the cold crystallization temperature (T c) increases and the melting temperature (T m). PET/PEN (50/50) has not cold crystallization peak. For other compositions,with increasing the mixing time,The cold crystallization temperature (T c) increases and the melting temperature (T m) decreases which are due to the decreases in the number-average sequence length decreasing. When the number-average sequence length is shorter than 7,the cold crystallization peak disappear and the melting peak disappear when the transesterification level is about 30%.