摘要
在双螺杆挤出机上熔融共混制备了聚丙烯 (PP) 有机累托石 (OREC)纳米复合材料 ,采用广角X 射线衍射 (WAXD)定性地分析了PP OREC纳米复合材料及纯PP的结晶形态 ,由半峰宽定性地判断了对应晶面法向的晶粒的大小 .结果表明有机累托石没有改变聚丙烯的结晶晶型 (纳米复合材料主要还是α晶型 ) ,但是细化了晶粒的尺寸 .采用差示扫描量热法 (DSC)定量地研究了复合材料的非等温熔融结晶动力学 ,对所得数据分别用Jeziorny法的Mo法进行了处理 ,表明非等温结晶动力学参数Zc 及Avrami指数n随冷却速率的增加而增加 ,复合材料的Avrami指数n大于纯PP的n ;对相同配比的纳米复合材料 ,随着结晶度的增加 ,单位结晶时间里达到一定结晶度所需要的降温速率F(T)增大 ,对同一个设定的结晶度 ,纳米复合材料的F(T)比纯PP的小 ,说明需要的降温速率减小 .所有这些均说明有机累托石可作为聚丙烯的结晶成核剂 .
The polypropylene (PP)/organic rectorite (OREC) nanocomposites were prepared by extruding the mixtures of OREC and PP using a twin-screw extruder. The crystallization behavior of PP and PP/OREC nanocomposites was studied by wide angle X-ray diffraction analysis (WAXD) performed at angle range of 10 similar to 25degrees and differential scanning calorimetry (DSC) conducted at constant cooling rate of 2.5 K/min, 5 K/min, 10 K/min and 15 K/min, respectively. The results of WAXD analysis show that the introduction of OREC does not change the crystal form of PP in the compocites. Non-isothermal crystallization kinetics of PP and PP/OREC nanocomposites was investigated by means of DSC, and the data are successfully analyzed by the Jeziomy and the Mo Zhishen methods. The non-isothermal crystallization kinetics parameter (Z(e)) and Avrami exponent(n) for PP and PP/OREC nanocomposites were reduced with cooling rate increasing. However, for PP/OREC nanocomposites, they are higher than those of PP at the same cooling rate. The characteristic cooling rate, F(T), increases with the degree of crystallinity for both PP and PP/OREC nanocomposites, but the values of F(T) of PP/OREC nanocomposites were lower than those of PP at the same degree of crystallinity. All the above analyse indicate that particles of OREC. have heterogeneous nucleation effects on PP matrix.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2004年第3期361-366,共6页
Acta Polymerica Sinica
基金
西北工业大学博士论文创新基金资助项目 (资助号CX2 0 0 3 2 4)