Montmorillontie (MMT) filled isotactic polypropylene (iPP) forms α-crystal. In this paper

β-MMT with β-nucleating surface supported by calcium pimelate (CaPA) was prepared through chemical reaction between Ca

2+

 and pimelic acid (PA). The results of FTIR spectroscopy and TGA analysis of β-MMT confirmed the formation of CaPA on the surface of MMT. The crystallization temperature

β-nucleating ability and the β-crystal content of β-MMT filled iPP composites were investigated by DSC and XRD analyses. It was observed that the crystallization temperature and intensity of βcrystal melting peak increased with decreasing MMT/PA mass ratio

indicating the enhanced β-nucleating ability. The XRD results showed that the β-crystal contents of β-MMT filled iPP composites increased with decreasing MMT/PA mass ratio. In addition

MMT filled iPP composites with β-crystal of 99% could be obtained by β-MMT prepared with MMT/PA mass ratio of 100. These results indicated that the β-nucleating agent supported on the surface of MMT particles could change from α- to β-nucleation in the MMT filled iPP composites.