Estimation of thermal transitions in poly(ethylene naphthalate): Experiments and modeling using isoconversional methods

Thermal transitions of PEN, such as the glass transition temperature and those occurring during isothermal or nonisothermal crystallization were investigated based on careful experiments and modeling with isoconversional methods. The latter was applied to DSC data to determine the effective activation energy for the glass transition in PEN. Using the same data and different thermal methods the dynamic fragility of PEN was evaluated. The Lauritzen-Hoffman (LH) parameters Kg and If were estimated using the secondary nucleation theory from both PLM and isothermal DSC after self-nucleation measurements. Regime II to land III toll transition at about 253 degrees C and 243 degrees C were concluded. Ellipticalshaped hedrite-like morphology was observed above 253 degrees C. Finally, isoconversional analysis was applied to both melt and glass non-isothermal crystallization data and the combined set of activation energies was found to be described by the theoretical Vyazovkin-Sbirrazzuoli equation using a single set of LH parameters coming from PLM measurements. (C) 2010 Elsevier Ltd. All rights reserved.