Non-isothermal cold crystallization kinetics of poly(3-hydoxybutyrate) filled with zinc oxide

• Non-isothermal cold crystallization kinetics of PHB filled with ZnO is presented.
• Pseudo-Avrami model is best for describing an individual crystallization condition.
• Mo model is allows to judge the kinetics of a condition untested in this work.
• ZnO affects the kinetics irregularly.

The non-isothermal cold crystallization kinetics of poly(3-hydroxybutyrate) (PHB) and PHB-ZnO composites, with ZnO content of 1%, 5% and 10% per weight, was investigated at different heating rates (5, 7.5, 10, 15, 20 and 30 °C/min) using differential scanning calorimetry. Both, Kissinger and Friedman activation energies predict correctly the slowest and fastest crystallizing composition. It was further found, that ZnO can neither be classified as a crystallization accelerator, nor as a crystallization inhibitor; its action is strongly concentration dependent. The empirical Pseudo-Avrami model has the best overall capability for fitting the experimental kinetic data. However, since the Pseudo-Avrami exponent was found to vary irregularly with heating rate and filler content, this model should not be applied for kinetic predictions of an arbitrary composition or an untested heating rate. In such cases, Mo's model should be used.