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The molecular relaxation mechanisms in cork as studied by thermally stimulated discharge currents

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Abstract

The dielectric relaxation mechanisms present in cork have been investigated in the temperature range -100 to 100 °C using the technique of thermally stimulated discharge currents. A relaxation mechanism was detected which showed a compensation behaviour as observed for the α-relaxation (or glass transition relaxation) of synthetic polymers and which lead us to attribute to cork a glass transition-like temperature of 18 °C. One lower temperature mechanism was also observed, with low activation enthalpy and entropy, which is presumably originated by local motions (internal rotations) of polar molecular groups. An upper T g relaxation of higher intensity was also detected which was attributed to large-scale non-cooperative motions of polymeric segments.

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Authors and Affiliations

  1. Centro de Química-Física, Molecular, IST, Av. Rovisco Pais, 1096, Lisboa Codex, Portugal

    J. F. Mano, N. T. Correia, J. J. Moura Ramos & B. Saramago

  2. Centro de Química Estrutural, Complexo I, IST, Av. Rovisco Pais, 1096, Lisboa Codex, Portugal

    B. Saramago

Authors
  1. J. F. Mano
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  2. N. T. Correia
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  3. J. J. Moura Ramos
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  4. B. Saramago
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Mano, J.F., Correia, N.T., Moura Ramos, J.J. et al. The molecular relaxation mechanisms in cork as studied by thermally stimulated discharge currents. JOURNAL OF MATERIALS SCIENCE 30, 2035–2041 (1995). https://doi.org/10.1007/BF00353030

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