Novel rheological model for the gelation kinetics of ionic polysaccharides

Authors

  • Romano Lapasin,

    Corresponding author
    1. Istituto di Chimica Applicata ed Industriale, Universitá di Trieste, Via Valerio 2, I-34127 Trieste, Italy
    • Istituto di Chimica Applicata ed Industriale, Universitá di Trieste, Via Valerio 2, I-34127 Trieste, Italy
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  • Sabrina Pricl,

    1. Istituto di Chimica Applicata ed Industriale, Universitá di Trieste, Via Valerio 2, I-34127 Trieste, Italy
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  • Sergio Paoletti,

    1. Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Universitá di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
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  • Flavio Zanetti

    1. Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Universitá di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
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Abstract

Homogeneous networks of an ionic polysaccharide (namely pectate) in the presence of divalent ions were prepared in situ by proper procedure and the kinetics of the gel formation was studied by means of a coaxial cylinder rheometer in oscillatory flow conditions. The stress response was expanded in a Fourier series and the variation of the components of the fundamental harmonic with time during the gelation process were examined. A model is proposed for the correlation between kinetic parameters such as the concentration of the species active during the gel formation and the rheological parameters that can be experimentally determined, like G′ and G′′. Considerations are developed concerning the mechanism that governs the gelation process under dynamic conditions.

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