The influences of copper nanoparticles content and cooling rate on non-isothermal crystallization behavior of low-density polyethylene/copper (LDPE/Cu) nanocomposites were investigated. Nanocomposites were prepared by extruding mixtures of pure LDPE and copper nanoparticles using melt-blending method in a single-screw extruder. Differential scanning calorimetry (DSC) was used to analyze their non-isothermal crystallization behavior. The results indicate that both the incorporation of copper nanoparticles and cooling rates influence the crystallization behaviors of the LDPE matrix significantly. Especially, the dependence of the effective activation energy on the relative extent of crystallization implies that the copper nanoparticles dispersed in the nanocomposites may act as a heterogeneous nucleation for the crystallization of the LDPE matrix, and that the presence of the copper nanoparticles may hinder the transport of the molecule chains at the same time, resulting in a decrease of the crystallization growth rate of the LDPE matrix. (C) 2004 Elsevier B.V. All rights reserved.