From α- to β-crystallization in multi-walled carbon nanotubes-filled polypropylene nanocomposites

Abstract

Multi-walled carbon nanotubes (MWCNTs)-filled polypropylene (PP) nanocomposites generally form α-crystal. In order to induce the transition from α-crystallization into β-crystallization of MWCNTs-filled PP nanocomposites, the calcium pimelate-supported MWCNTs were prepared. The effect of calcium pimelate-supported MWCNTs on the crystallization behavior and melting characteristics and spherulitic morphology of PP was investigated by differential scanning calorimetry, X-ray diffraction, and polarizing optical microscopy. The β-nucleating ability of calcium pimelate-supported MWCNTs prepared with different mass ratios of MWCNTs/pimelic acid and its influence on the crystallization of PP nanocomposites was discussed. It is found that the MWCNTs supported by calcium pimelate can change from α-nucleation of MWCNTs surface into β-nucleation and induce β-crystallization in the MWCNTs-filled PP nanocomposites. The MWCNTs-filled PP nanocomposites prepared with MWCNTs/pimelic acid mass ratio of 10/1 can completely form β-crystal. The β-crystal content of the PP nanocomposites filled by MWCNTs kept at high level and was little influenced by MWCNTs contents. This finding is great significant to develop MWCNTs-filled β-PP nanocomposites.