Nonisothermal and isothermal crystallization kinetics of nylon-12

摘要

The isothermal and nonisothermal crystallization behavior of Nylon 12 was investigated using differential scanning calorimetry (DSC). An Avrami analysis was used to study the isothermal crystallization kinetics of Nylon 12, the Avrami exponent (n) determined and its relevance to crystal growth discussed and an activation energy for the process evaluated using an Arrhenius type expression. The Lauritzen and Hoffman analysis was used to examine the spherulitic growth process of the primary crystallization stage of Nylon 12. The surface-free energy and work of chain folding were calculated using a procedure reported by Hoffman and the work of chain folding per molecular fold (sigma) and chain stiffness of Nylon 12(q) was calculated and compared to values reported for Nylons 6,6 and 11. The Jeziorny modification of the Avrami analysis, Caze and Chuah average Avrami parameter methods and Ozawa equation were used in an attempt to model the non-isothermal crystallization kinetics of Nylon, 12. A combined Avrami and Ozawa treatment, described by Liu, was used to more accurately model the nonisothermal crystallization kinetics of Nylon 12. The activation energy for nonisothermal crystallization processes was determined using the Kis-singer method for Nylon 12 and compared with values reported previously for Nylon 6,6 and Nylon 11.(c) 2008 Wiley Periodicals, Inc.