The melting behavior and the crystn. kinetics of poly(dithiotriethylene adipate) (PSSTEA) were investigated by differential scanning calorimetry and hot-stage optical microscopy. The obsd. multiple endotherms, commonly displayed by polyesters, were influenced by the crystn. temp. (T c) and ascribed to melting and recrystn. processes. Linear and nonlinear theor. treatments were applied to est. the equil. melting temp. for PSSTEA, using the cor. values of the melting temp.; the nonlinear estn. yielded a higher value by about 15 °C. Isothermal crystn. kinetics were analyzed according to the Avrami's theory. Values of the Avrami's exponent n close to 3 were obtained, independently of T c, in agreement with a crystn. process originating from predetd. nuclei and characterized by three-dimensional spherulitic growth. As a matter of fact, space-filling spherulites were obsd. by optical microscopy at all T c's. The rate of crystn. became lower as T c increased, as usual at low undercooling, the crystn. process being controlled by nucleation.

Poly(dithiotriethylene adipate): Melting behavior, crystallization kinetics and morphology

SIRACUSA, VALENTINA;
2005-01-01

Abstract

The melting behavior and the crystn. kinetics of poly(dithiotriethylene adipate) (PSSTEA) were investigated by differential scanning calorimetry and hot-stage optical microscopy. The obsd. multiple endotherms, commonly displayed by polyesters, were influenced by the crystn. temp. (T c) and ascribed to melting and recrystn. processes. Linear and nonlinear theor. treatments were applied to est. the equil. melting temp. for PSSTEA, using the cor. values of the melting temp.; the nonlinear estn. yielded a higher value by about 15 °C. Isothermal crystn. kinetics were analyzed according to the Avrami's theory. Values of the Avrami's exponent n close to 3 were obtained, independently of T c, in agreement with a crystn. process originating from predetd. nuclei and characterized by three-dimensional spherulitic growth. As a matter of fact, space-filling spherulites were obsd. by optical microscopy at all T c's. The rate of crystn. became lower as T c increased, as usual at low undercooling, the crystn. process being controlled by nucleation.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/7576
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