高抗冲共聚聚丙烯／茂金属聚乙烯蜡的相容性和结晶行为研究

Miscibility and Crystallization Behavior of Metallocene Polyethylene Wax Modified Polypropylene Copolymer with High Impact Resistance

通过示差扫描量热仪(DSC)对高抗冲共聚聚丙烯(PP copolymer)／茂金属聚乙烯蜡(MPE wax)共混体系的熔点和结晶温度进行研究,发现MPE wax在熔融和结晶过程中都没有自己的特征峰出现,证明其已经在PP copolymer结晶时完全进入了晶体结构中,而在降温过程中,MPE wax不但没有降低PP copolymer的结晶温度,反而使之在较高的温度下结晶,显示出两者良好的相容性和MPE wax的成核作用。结晶动力学数据显示MPE wax的加入对体系的结晶行为有所影响,减缓了结晶过程并降低了体系的结晶活化能,而结晶动力学参数显示MPE wax的加入使共聚聚丙烯的结晶行为与降温速率的依赖性降低,并使α值趋于1,Ozawa指数趋近于Avrami指数。MPE wax对PP copolymer的力学性能影响很小,能很好保持PP copolymer的应用性能。

Melting and crystallization processes of polypropylene copolymer/MPE wax blend were studied with a differential scanning calorimetry. Since the loading of MPE wax was low, no melting or crystallization peaks for MPE wax were given. However, the crystallization peak for PP moved to higher temperatures as the loading of MPE wax increased. At constant cooling rate, the velocity and the activation energy of crystallization of PP were decreased with increasing MPE wax content. Incorporation of MPE wax had not affected the mechanical properties of PP.