Morphological studies of polypropylene–nanoclay composites



Polypropylene–clay nanocomposites were prepared by a solution technique and a subsequent melt-mixing process. A titanate coupling agent was used to improve the compatibility of the nanoclay particles with the polypropylene. The dispersion of the nanoclay particles in polypropylene was studied with X-ray diffraction (XRD) and transmission electron microscopy (TEM). An increased d-spacing value of the clay particles in the nanocomposites was observed, and it was compared with the values of as-mined (pristine) and as-received (organophilic) clay particles. The number of intercalated layers in a single clay crystallite was determined to be 4, and the number was confirmed with XRD data and TEM images. On the basis of the Daumas–Herold model (which is widely used for graphite intercalation compounds), the stage 2 and stage 3 structures of montmorillonite particles in polypropylene were recommended. A study on the stage structure suggested a way of determining the presence of polymer molecules in the clay galleries. The results confirmed the existence of single-layered platelets with improved dispersion in polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 218–226, 2005