Assessing the Effects of Process Temperature on Crystallization Kinetics of Polyphenylene Sulfide Utilizing Differential Scanning Calorimetry (DSC)

摘要

The dependence of process melting temperature of polyphenylene sulfide (PPS) on crystallization temperature and kinetics was demonstrated by a simple DSC experiment in which the sample was held at isothermally at several temperatures above the equilibrium melting temperature for five minutes to destroy any crystals or other structure that may aid in nucleation. Cooling the samples at 10 C/ min showed the crystallization temperatures asymptotically converge at a crystallization temperature that corresponds to an isothermal hold temperature of 350 C or approximately 50 C above the equilibrium melting temperature. A non-isothermal kinetic study on PPS resin held at the lowest, highest and an intermediate isothermal temperature show a correlation in crystallization activation energy confirming that remaining 'seed' crystals or other structure aid in nucleation. The kinetic parameters were calculated from rate data obtained from non-isothermal or dynamic DSC experiments using the Avrami and Malkin macro kinetic models and Friedman's isoconversional approach using data taken directly from the DSC experiment.