| Autor: |
Kristiawan, Magdalena, Chaunier, Laurent, Della Valle, Guy, Lourdin, Denis, Guessasma, Sofiane |
| Předmět: |
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| Zdroj: |
Rheologica Acta; Jul2016, Vol. 55 Issue 7, p597-611, 15p |
| Abstrakt: |
The effects of temperature and moisture content on the linear viscoelastic behavior of extruded amorphous potato starch were studied using dynamic mechanical analysis (DMA) from the glassy to the rubbery state. Sinusoidal tensile tests were carried out in multifrequency mode in the range of 0.1-40 Hz, with a temperature ramp of 20 to 135 °C. The water loss during DMA thermal scanning was evaluated by gravimetric analysis of batch sampling in parallel experiments that simulated temperature evolution. Loss and storage moduli were then corrected on real moisture content. Using the time-temperature superposition principle, master curves were obtained for loss and storage moduli over 18 decades in frequency. The generalized Maxwell model, in the form of a Prony series obtained from master curve fitting, was used to predict the relaxation modulus. Results showed that the relaxation modulus varied over a wide range, from 2650 MPa ( t = 10 s, 20 °C, 8 % w.b.) to 0.16 MPa ( t = 10 s, 95 °C, 16 % w.b.). The obtained constitutive equation was effective to predict the linear viscoelasticity behavior of potato starch in a wide range of thermomechanical conditions, as shown by the results of simulations of tensile experiments using finite elements. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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