Nonisothermal crystallization kinetics of linear bimodal-polyethylene (LBPE) and LBPE/low-density polyethylene blends

Nonisothermal crystallization kinetics of linear bimodal-polyethylene (LBPE) and the blends of LBPE/low-density polyethylene (LDPE) were studied using DSC at various scanning rates. The Avrami analysis modified by Jeziorny and a method developed by Mo were employed to describe the nonisothermal crystallization process of LBPE and LBPE/LDPE blends. The theory of Ozawa was also used to analyze the LBPE DSC data. Kinetic parameters such as, for example, the Avrami exponent (n), the kinetic crystallization rate constant (Z(c)), the crystallization peak temperature (T-P), and the half-time of crystallization (t(1/2)) were determined at various scanning rates. The appearance of double melting peaks and double crystallization peaks in the heating and cooling DSC curves of LBPE/LDPE blends indicated that LBPE and LDPE could crystallize, respectively. As a result of these studies, the Z(c) of LBPE increases with the increase of cooling rates and the T of LBPE for LBPE/LDPE blends first increases with increasing LBPE content in the blends and reaches its maximum, then decreases as the LBPE content further increases. (C) 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2431-2437, 2003.