The β-nucleating effect of wollastonite-filled isotactic polypropylene composites

Wollastonite (W) with beta-nucleating effect (beta-W-100) for iPP crystallization was obtained through reaction between Ca2+ in wollastonite and pimelic acid (PA) and the beta-iPP composites filled by different content of beta-W-100 were prepared. The effect of PA and wollastonite contents on beta-nucleation, crystallization and melting behavior, and crystalline morphology of W and beta-W-100-filled iPP composites was investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction, and polarizing optical microscopy. The results indicated that incorporation of W and beta-W-100 increase the crystallization peak temperature of iPP due to its heterogeneous nucleating ability. And iPP/W composites predominantly crystallize in the alpha-phase iPP and iPP/beta-W-100 composites in the beta-phase iPP. The results of DSC multi-scanning in same and different melting temperatures showed that beta-W-100 not only has strong heterogeneous beta-nucleating effect but also DSC multi-scanning in same and different melting temperatures has no influence on the heterogeneous beta-nucleating effect of beta-W-100. The beta-iPP containing high wollastonite content with high beta-phase content can be easily prepared.