磷酸盐与山梨醇类成核剂成核PP样品等温结晶行为与熔融特性

用差动扫描量热计（DSC）研究了一种有机磷酸盐类成核剂（A）、山梨醇类成核剂（D）成核PP和纯PP的等温结晶行为和熔融特性。结果表明成核样品缩短PP的半结晶时间，成核型A比D更明显；纯PP样品的半结晶时间正比于结晶温度，而成核PP的半结晶时间与结晶温度的关系在结晶温度低时，依赖性较纯PP的小，而在高结晶温度，半结晶时间对结晶温度的依赖性比较PP的大。成核剂的加入使PP结晶完善性提高，且熔融峰发生改变，熔融峰高温区出现一肩峰；而纯PP在低温区有一很宽的肩峰。根据半结晶时间，2种成核剂的成核效果为A＞D，与非等温结晶的结果一致。

Isothermal Cyrstallization Behavior and Melting Characteristics of Injection Sample of Nucleated Polypropylene

The isothermal crystallization behavior and melting characteristics of polypropylene (PP) nucleated by a phosphate nucleating agent (A) and a sorbital nucleating agent (D) were studied by differential scanning calorimetry.Compared with pure PP,nucleated PP showed a shorter half time of crystallization.For the pure PP,a linear dependence of half time of crystallization on the crystallization temperature was observed.However,nucleated PP showed a little dependence of half time of crystallization on crystallization temperature when nucleated PP crystallized at low temperature;while a stronger dependence of half time of crystallization was observed when nucleated PP crystallized at high temperature.Addition of nucleating agent improved crystal perfection of PP.A shoulder peak in the high temperature range of melting peak of nucleated PP but a wide peak in the low temperature range of melting peak of pure PP were observed.Obviously,PP and nucleated PP form different distribution of crystal perfection in the isothermal crystallization process.According to the half time of crystallization,nucleating agent A is more effective than D for PP crystallization.