The thermal degradation of linear low-density polyethylene (LLDPE) and linear low-density silane-crosslinked polyethylene (SXLPE) was studied. Kinetic evaluations were performed by model-free kinetic analysis and multivariate nonlinear regression. Apparent kinetic parameters for the overall degradation were determined. The results show that the thermal stability of SXLPE was higher than that of LLDPE. Their decomposition reaction model was a single-step process of an nth-order reaction. (c) 2005 Wiley Periodicals, Inc.