环形对苯二甲酸丁二醇酯与催化剂混合体系的流变性能

利用高温旋转黏度计,采用梯度降温的方法,研究CBT(环形对苯二甲酸丁二醇酯)树脂与CBT/催化剂混合体系在特定条件下的流变性能。结果表明:采用梯度降温方法可准确获得CBT纯树脂的真实表观黏度。CBT树脂的表观黏度随温度的降低而升高,随转速的加快而降低,在170~180℃下呈现出明显的剪切变稀现象。CBT/催化剂混合体系的反应速率随催化剂浓度的增加而加快。相同浓度下,锡含量较高的CBT/T9体系相对CBT/DBTL体系反应速率更快。较高的温度使催化剂的挥发程度加剧,结晶速率变慢,导致CBT/催化剂混合体系的反应速率随温度升高而变慢。最后研究了催化剂种类、浓度和成型温度对成型窗口时间的影响。

Rheological properties of a mixture of cyclic butylene terephthalate and catalyst

A new strategy with gradient cooling method was proposed for characterizing the rheological properties of CBT pure resin and CBT/catalyst mixture system under special molding conditions based on a digital high-temperature rotary viscometer.The results show that the apparent viscosity of CBT pure resin can be accurately obtained by using the gradient cooling method.The apparent viscosity of CBT pure resin is increased with the decrease of temperature,and is decreased with the increase of the rotating speed,and shows a significant shear thinning phenomenon at 170-180℃.The reaction rate of the CBT/catalyst resin system is increased with the increase of the catalyst content,and the molding window time is shortened.Under the same concentration conditions,the CBT/T9 system with higher tin content has a faster reaction rate than the CBT500/DBTL system.With the increase of molding temperature,the reaction rate of CBT/catalyst system shows the trend of slowing down.This may be due to the increased volatilization of the catalyst and the decreased crystallization rate at higher molding temperature.Finally,the effects of different catalyst types,different concentrations and molding temperatures on the molding window time of CBT resin system were studied.