热氧处理聚丙烯粉料的DSC曲线双峰研究

Study on the Double-Peaks of the Curves of DSC of PP Powder under Thermooxidative Treatment

发现热氧处理的聚丙烯粉料的DSC曲线存在着熔融双峰现象。可以用熔融双峰来判断聚丙烯粉料的热氧老化是否发生,并评估其热氧降解的程度。第一次升温曲线小平台状熔融峰的出现表明热氧老化开始发生。第二次升温曲线孪生双峰的出现则表明热氧老化的程度已经相当严重。小平台状熔融峰是回火效应留下的DSC印记,而孪生双峰的成因则是降解程度提高后β晶的出现和增多。

It has been found that there existed melting double-peak phenomenon in the DSC curves of PP powder, which could be used to judge whether the thermooxidative aging took place or to evaluate the degree of thermooxidative degradation of PP powder. The appearance of the small platform-shaped melting peak in the first temperature-rise curve indicates that the thermooxidative aging takes place and the emergence of twin-peaks in the second temperature-rise curve shows that great thermooxidative degradation occurred. The small platform-shaped melting peak was the imprinting of the effect of tempering and the twin-peaks were the results of the increase of the β crystal generated by the raise of the thermooxidative degradation.