https://doi.org/10.15255/KUI.2017.038
Published: Kem. Ind. 67 (5-6) (2018) 195–206
Paper reference number: KUI-38/2017
Paper type: Original scientific paper
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Kinetics of Isothermal Crystallization for TPU/PP Blends

E. Govorčin Bajsić and B. Ormuž Pavić

Abstract

The kinetics of isothermal crystallization and crystalline structure of thermoplastic polyurethane and polypropylene (TPU/PP) and thermoplastic polyurethane, polypropylene blends with addition of talc (TPU/PP/T) of different composition ratios (80/20, 50/50 and 20/80) were studied under isothermal conditions by differential scanning calorimetry (DSC). Crystallization studies were carried out in the temperature range of 116 °C to 132 °C. It was found that crystallization was faster for TPU/PP/T blends. Isothermal crystallization kinetics were described by means of the Avrami equation. The effects of different isothermal temperatures were studied by comparing the values of kinetic parameters, such as the Avrami exponent, n, the kinetic constant of the crystallization rate, k, and the crystallization half-time, t_1/2. The Avrami exponent was evaluated to be in the range of 1.18–2.31. The results indicated the two-dimensional growth of crystalline units. The isothermal crystallization kinetics showed that the addition of talc increased the isothermal crystallization temperature and the crystallization rate constant, k, of TPU/PP blends. For the given crystallization temperatures, the crystallization half-time, t_1/2, for the TPU/PP/T blends was lower than the corresponding value for TPU/PP blends.

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Keywords

polypropylene, thermoplastic polyurethane, differential scanning calorimetry, isothermal crystallization, kinetics of crystallization