Crystallization behavior of polyethylene/montmorillonite (MMT) nanocomposites by in situ polymerization

The crystallization kinetics isothermally, the melting and crystallization behavior of pure HDPE, HDPE/MMT blends and HDPE/MMT nanocomposites prepared by in situ polymerization were investigated by DSC. The crystallinity, linear growth rate of spherulites, equilibrium melting temperature and crystallization ability of HDPE are similar to that of its blends with MMT. However, the crystallinity and equibrium melting temperature of PE/MMT nanocomposites by in situ polymerization are higher than that of HDPE. The linear growth rate of spherulites and crystallization ability of the crystals formed at the same undercooling degree are lower for HDPE/MMT nanocomposites in comparison with HDPE. On the other hand, they are much higher when the crystals crystallized from melt at the same temperature, tc, for HDPE/MMT nanocomposite. The lateral surface free energy, σ, of the developing crystals is the smallest for HDPE, secondly it is for the HDPE/MMT blends, the HDPE/MMT nanocomposites exhibit the largest σ and it increased gradually with increasing the content of MMT in these composites.