The nonisothermal crystallization kinetics of high-density polyethylene (HDPE) and polyethylene (PE)/PE-grafted maleic anhydride (PE-g-MAH)/organic-montmorillonite (Org-MMT) nanocomposite were investigated by differential scanning calorimetry (DSC) at various cooling rates. Avrami analysis modified by Jeziorny, Ozawa analysis, and a method developed by Liu well described the nonisothermal crystallization process of these samples. The difference in the exponent n, m, and a between HDPE and the nanocomposite indicated that nucleation mechanism and dimension of spherulite growth of the nanocomposite were different from that of HDPE to some extent. The values of half-time (t(1/2)), K(T), and F(T) showed that the crystallization rate increased with the increase of cooling rates for HDPE and composite, but the crystallization rate of composite was faster than that of HDPE at a given cooling rate. Moreover, the method proposed by Kissinger was used to evaluate the activation energy of the mentioned samples. It was 223.7 kJ/mol for composite, which was much smaller than that for HDPE (304.6 kJ/mol). Overall, the results indicated that the addition of Org-MMT and PE-g-MAH could accelerate the overall nonisothermal crystallization process of PE. (C) 2004 Wiley Periodicals, Inc.