聚丙烯/凹凸棒土纳米复合材料结晶形态和形貌研究

采用熔融共混的方法 ,制备聚丙烯 凹凸棒土纳米复合材料 .通过X射线衍射 (XRD)分析凹凸棒土在聚丙烯复合材料中晶面间距的变化以及对聚丙烯晶型的影响 ,结果表明凹凸棒土在复合材料中晶面间距没有变化 ;聚丙烯晶型没有发生变化但晶粒尺寸增加了 .用示差扫描量热法 (DSC)分析聚丙烯复合材料的结晶度的变化 ,发现凹凸棒土的加入使复合材料的结晶温度提高 ,结晶速率增大 ,结晶度增加 .用偏光显微镜(POM)观察凹凸棒土对聚丙烯球晶的影响 ,结果表明凹凸棒土的加入起到了成核剂的作用 ,使得聚丙烯球晶尺寸减小 ,当凹凸棒土的加入量到 10 %左右时 ,观察不到完整的球晶 .利用扫描电子显微镜 (SEM)和原子力显微镜 (AFM)观察凹凸棒土在聚丙烯中的分散 ,发现凹凸棒土在聚丙烯基体中分散比较均匀 ,但呈无序分布 .

STUDY ON CRYSTALLIZATION AND MORPHOLOGY OF POLYPROPYLENE/ATTAPULGITE NANOCOMPOSITES

Polypropylene/attapulgite nanocomposites were prepared by melt blending. The effects of attapulgite on crystallization of PP were investigated by means of X-ray diffraction(XRD). It was found that the (110) plane spacing of attapulgite in the composites did not expand. It implies that no intercalation phenomenon occurs in these composites. The add of attapulgite made the microcrystal dimension of polypropylene increase. The thermal behavior of PP nanocomposites was analysized by differential scanning calorimetry(DSC), and the results showed that a proper amount of attapulgite can increase the crystallization temperature and crystallization rate of PP, and so make the crystallinity increase. The spherulite morphology was observed by polarized optical microscopy(POM), and the addition of attapulgite acted as a nucleating agents for the crystallization of PP and reduced the spherulite dimension. When the content of attapulgite reached about 10 percent, no spherulite was observed. The morphology of attapulgite particles and their dispersion in the PP matrix were analysized by scanning electron microscopy(SEM) and atomic force microscopy(AFM). It was found that the attapulgite particles have a fibrous or rodlike morphology and almost homogeneously dispersed in the PP matrix, without preferential orientation.