Investigation of the properties of fully reacted unstoichiometric polydimethylsiloxane networks and their extracted network fractions

Sarah Maria Grundahl Frankær, Mette Krog Jensen, Anca Gabriela Bejenariu, Anne Ladegaard Skov

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Abstract

We investigated the linear dynamic response of a series of fully reacted unstoichiometric polydimethylsiloxane (PDMS) networks and of the two corresponding network fractions namely the sol and the washed network. The sol and
the washed network were separated by a simple extraction process. This way it was possible to obtain rheological data from the washed network without interference from the sol fraction, and furthermore from the sol fraction without interference from the elastic washed network. When the stoichiometry increased towards perfectly reacted networks and beyond we observed harder networks both qualitatively and by rheology and the properties of the two fractions became more and more different. At the gel point, the sol fraction and the washed network have more or less identical properties which our data also shows. The storage and loss moduli, G′ and G′′, were analysed with the gel equation as proposed by Winter and Chambon(1986; 1987). We observed that one of the investigated samples which before
the swelling experiment did not show any elastic response gave an elastic washed network after swelling, this was verified by analysis with the gel equation. We also calculated the weight fraction of the sol fraction by using the theory by Villar et al. (1996) and compared these with experimentally found values.
Original languageEnglish
JournalRheologica Acta
Volume51
Issue number6
Pages (from-to)559-567
ISSN0035-4511
DOIs
Publication statusPublished - 2012

Keywords

  • Polymer networks
  • Gel
  • Soluble structures
  • Rheology
  • Linear viscoelastic properties

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