PE/ORG-MMT nanocomposites - Non-isothermal crystallization kinetics

The non-isothermal crystallization kinetics of polyethylene (PE), PE/organic-montmorillonite (Org-MMT) composites were investigated by differential scanning calorimetry (DSC) with various cooling rates. The Avrami analysis modified by Jeziorny and a method developed by Mo were employed to describe the non-isothermal crystallization process of these samples very well. The difference in the exponent n between PE and PE/Org-MMT nanocomposites, indicated that non-isothermal kinetic crystallization corresponded to tridimensional growth with heterogeneous nucleation. The values of half-time, Z(c) and F(T) showed that the crystallization rate increased with the increasing of cooling rates for PE and PE/Org-MMT composites, but the crystallization rate of PE/Org-MMT composite was faster than that of PE at a given cooling rate. The method developed by Ozawa did not describe the non-isothermal crystallization process of PE very well. Moreover, the method proposed by Kissinger was used to evaluate the activation energy of the mentioned samples. The results showed that the activation energy of PE/Org-MMT was greatly larger than that of PE.