In the present work, we characterize the rheological behavior of 10 nearly monodisperse poly(ethyl acrylate) samples, whose molar mass ranges from 1200 to 150 000 g/mol. The poly(ethyl acrylate)s were obtained by means of a controlled/living radical polymerization technique. The time-temperature superposition principle works, and the T dependence of the horizontal shift factor a(Tr)(T) is fairly well described by the Williams-Landel-Ferry law. Furthermore, the zero-shear viscosity dependence on the temperature, for all the investigated samples, has resulted to be well described by means of Vogel-Fulcher laws. The mass dependence of thermal parameters such as the Vogel temperature T-0 and the pseudo-activation energy T-b has been worked out and compared to the mass dependence of the glass transition temperature T, This leads us to propose here a coherent way to describe their behavior and estimate several microscopic parameters in terms of free volume. Moreover, the molar mass dependence of material parameters has been investigated. The zero-shear viscosity eta at different temperatures has been evaluated, and the critical mass value has been found to be M-c = 26 000 g/mol. The ratio between the critical M-c and the entanglement mass M-e has been found to be about 2.2 from the evaluation of the plateau modulus G(N)(0). A mass dependence analysis of the steady-state compliance J(e)(0) has also been carried out from which the second critical mass M-c' is inferred.

Rheological and Thermal Properties of Narrow Distribution Poly(ethyl acrylate)s

ANDREOZZI, LAURA;CASTELVETRO, VALTER;FAETTI, MASSIMO;GIORDANO, MARCO;ZULLI, FABIO
2006

Abstract

In the present work, we characterize the rheological behavior of 10 nearly monodisperse poly(ethyl acrylate) samples, whose molar mass ranges from 1200 to 150 000 g/mol. The poly(ethyl acrylate)s were obtained by means of a controlled/living radical polymerization technique. The time-temperature superposition principle works, and the T dependence of the horizontal shift factor a(Tr)(T) is fairly well described by the Williams-Landel-Ferry law. Furthermore, the zero-shear viscosity dependence on the temperature, for all the investigated samples, has resulted to be well described by means of Vogel-Fulcher laws. The mass dependence of thermal parameters such as the Vogel temperature T-0 and the pseudo-activation energy T-b has been worked out and compared to the mass dependence of the glass transition temperature T, This leads us to propose here a coherent way to describe their behavior and estimate several microscopic parameters in terms of free volume. Moreover, the molar mass dependence of material parameters has been investigated. The zero-shear viscosity eta at different temperatures has been evaluated, and the critical mass value has been found to be M-c = 26 000 g/mol. The ratio between the critical M-c and the entanglement mass M-e has been found to be about 2.2 from the evaluation of the plateau modulus G(N)(0). A mass dependence analysis of the steady-state compliance J(e)(0) has also been carried out from which the second critical mass M-c' is inferred.
Andreozzi, Laura; Castelvetro, Valter; Faetti, Massimo; Giordano, Marco; Zulli, Fabio
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/107814
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