Preparation and properties of polypropylene/org-attapulgite nanocomposites

Polypropylene (PP)/org-attapulgite (ATP)nanocomposites were prepared by melt blending in a mixer apparatus. Org-attapulgite was attained by silane coupling agent modification first and then graft-polymerization with butyl acrylate. Scanning electron microscopy (SEM)and transmission electron microscopy (TEM)were used to assess the clay morphology and the dispersion of the org-attapulgite, respectively. The changes of crystalline structure for PP nanocomposites were characterized by X-ray diffraction (XRD). The mechanical properties of PP/attapulgite nanocomposites were studied through tensile and impact tests. The thermal and dynamic mechanical properties were characterized by differential scanning calorimetry (DSC)and dynamic mechanical analysis (DMA). The strength and stiffness of PP/org-ATP nanocomposites were both improved significantly in the presence of organic attapulgite. In addition, the incorporation of org-ATP also gave rise to an increase of the storage modulus and the changes of the glass transition temperature for PP composites. TEM and XRD results revealed the addition of attapulgite did not change the crystal structure of PP, however org-attapulgite acted as nucleating agents for the crystallization of PP.