The length of cooperativity at the glass transition in poly(vinyl acetate) from the modeling of the structural relaxation process

J. L. Gómez Ribelles, A. Vidaurre Garayo, J. M G Cowie, R. Ferguson, S. Harris, I. J. McEwen

Research output: Contribution to journalArticle

Abstract

The structural relaxation process of poly(vinyl acetate) has been studied by differential scanning calorimetry. The sample was subjected to different thermal treatments including an isothermal annealing at temperature Ta for a time ta. The heat capacity cp(T) was measured during a heating scan. Thus, the experimental results consist of a series of cp(T) curves determined after thermal histories with different values of Ta and ta. The experimental results were compared with the prediction of a multiparameter phenomenological model described in references [15,16]. This model follows the evolution of the configurational entropy of the sample during the whole thermal history. The parameters of the model were calculated by simultaneous fits to five cp(T) curves, corresponding to different thermal histories (the parameters of the model have the character of material parameters, independent of the thermal history). This allows the determination of the temperature dependence of the relaxation times and the ß parameter of the Kohlrausch - Williams - Watts equation. From these parameters and an estimate of the internal rotational barrier obtained by molecular mechanics calculations, the size of the smallest cooperative rearranging region in the Adam-Gibbs theory was calculated. This result is compared with the length of cooperativity calculated from the temperature fluctuation theory proposed by Donth. © 1998 Elsevier Science Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)183-192
Number of pages10
JournalPolymer
Volume40
Issue number1
Publication statusPublished - Jan 1999

Fingerprint

acetates
histories
glass
fluctuation theory
curves
heat measurement
relaxation time
specific heat
entropy
temperature dependence
annealing
heating
scanning
temperature
estimates
predictions

Keywords

  • Glass transition
  • Physical ageing
  • Structural relaxation

Cite this

Gómez Ribelles, J. L., Vidaurre Garayo, A., Cowie, J. M. G., Ferguson, R., Harris, S., & McEwen, I. J. (1999). The length of cooperativity at the glass transition in poly(vinyl acetate) from the modeling of the structural relaxation process. Polymer, 40(1), 183-192.
Gómez Ribelles, J. L. ; Vidaurre Garayo, A. ; Cowie, J. M G ; Ferguson, R. ; Harris, S. ; McEwen, I. J. / The length of cooperativity at the glass transition in poly(vinyl acetate) from the modeling of the structural relaxation process. In: Polymer. 1999 ; Vol. 40, No. 1. pp. 183-192.
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abstract = "The structural relaxation process of poly(vinyl acetate) has been studied by differential scanning calorimetry. The sample was subjected to different thermal treatments including an isothermal annealing at temperature Ta for a time ta. The heat capacity cp(T) was measured during a heating scan. Thus, the experimental results consist of a series of cp(T) curves determined after thermal histories with different values of Ta and ta. The experimental results were compared with the prediction of a multiparameter phenomenological model described in references [15,16]. This model follows the evolution of the configurational entropy of the sample during the whole thermal history. The parameters of the model were calculated by simultaneous fits to five cp(T) curves, corresponding to different thermal histories (the parameters of the model have the character of material parameters, independent of the thermal history). This allows the determination of the temperature dependence of the relaxation times and the {\ss} parameter of the Kohlrausch - Williams - Watts equation. From these parameters and an estimate of the internal rotational barrier obtained by molecular mechanics calculations, the size of the smallest cooperative rearranging region in the Adam-Gibbs theory was calculated. This result is compared with the length of cooperativity calculated from the temperature fluctuation theory proposed by Donth. {\circledC} 1998 Elsevier Science Ltd. All rights reserved.",
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Gómez Ribelles, JL, Vidaurre Garayo, A, Cowie, JMG, Ferguson, R, Harris, S & McEwen, IJ 1999, 'The length of cooperativity at the glass transition in poly(vinyl acetate) from the modeling of the structural relaxation process', Polymer, vol. 40, no. 1, pp. 183-192.

The length of cooperativity at the glass transition in poly(vinyl acetate) from the modeling of the structural relaxation process. / Gómez Ribelles, J. L.; Vidaurre Garayo, A.; Cowie, J. M G; Ferguson, R.; Harris, S.; McEwen, I. J.

In: Polymer, Vol. 40, No. 1, 01.1999, p. 183-192.

Research output: Contribution to journalArticle

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AU - Gómez Ribelles, J. L.

AU - Vidaurre Garayo, A.

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AU - Ferguson, R.

AU - Harris, S.

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N2 - The structural relaxation process of poly(vinyl acetate) has been studied by differential scanning calorimetry. The sample was subjected to different thermal treatments including an isothermal annealing at temperature Ta for a time ta. The heat capacity cp(T) was measured during a heating scan. Thus, the experimental results consist of a series of cp(T) curves determined after thermal histories with different values of Ta and ta. The experimental results were compared with the prediction of a multiparameter phenomenological model described in references [15,16]. This model follows the evolution of the configurational entropy of the sample during the whole thermal history. The parameters of the model were calculated by simultaneous fits to five cp(T) curves, corresponding to different thermal histories (the parameters of the model have the character of material parameters, independent of the thermal history). This allows the determination of the temperature dependence of the relaxation times and the ß parameter of the Kohlrausch - Williams - Watts equation. From these parameters and an estimate of the internal rotational barrier obtained by molecular mechanics calculations, the size of the smallest cooperative rearranging region in the Adam-Gibbs theory was calculated. This result is compared with the length of cooperativity calculated from the temperature fluctuation theory proposed by Donth. © 1998 Elsevier Science Ltd. All rights reserved.

AB - The structural relaxation process of poly(vinyl acetate) has been studied by differential scanning calorimetry. The sample was subjected to different thermal treatments including an isothermal annealing at temperature Ta for a time ta. The heat capacity cp(T) was measured during a heating scan. Thus, the experimental results consist of a series of cp(T) curves determined after thermal histories with different values of Ta and ta. The experimental results were compared with the prediction of a multiparameter phenomenological model described in references [15,16]. This model follows the evolution of the configurational entropy of the sample during the whole thermal history. The parameters of the model were calculated by simultaneous fits to five cp(T) curves, corresponding to different thermal histories (the parameters of the model have the character of material parameters, independent of the thermal history). This allows the determination of the temperature dependence of the relaxation times and the ß parameter of the Kohlrausch - Williams - Watts equation. From these parameters and an estimate of the internal rotational barrier obtained by molecular mechanics calculations, the size of the smallest cooperative rearranging region in the Adam-Gibbs theory was calculated. This result is compared with the length of cooperativity calculated from the temperature fluctuation theory proposed by Donth. © 1998 Elsevier Science Ltd. All rights reserved.

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Gómez Ribelles JL, Vidaurre Garayo A, Cowie JMG, Ferguson R, Harris S, McEwen IJ. The length of cooperativity at the glass transition in poly(vinyl acetate) from the modeling of the structural relaxation process. Polymer. 1999 Jan;40(1):183-192.