Model for anomalous moisture diffusion through a polymer-clay nanocomposite

A. D. Drozdov, J. De, R. K. Gupta, A. P. Shah

Research output: Contribution to journalArticlepeer-review

103 Scopus citations

Abstract

Experimental data are reported on moisture diffusion and the elastoplastic response of an intercalated nanocomposite with vinyl ester resin matrix and montmorillonite clay filler at room temperature. Observations in diffusion tests showed that water transport in the neat resin is Fickian, whereas it becomes anomalous (non-Fickian) with the growth of the clay content. This transition is attributed to immobilization of penetrant molecules on the surfaces of hydrophilic clay layers. Observations in uniaxial tensile tests demonstrate that the response of vinyl ester resin is strongly elastoplastic, whereas an increase in the clay content results in a severe decrease of plastic strains observed as a noticeable reduction in the curvatures of the stress-strain diagrams. This is explained by slowing down the molecular mobility in the host matrix driven by confinement of chains in galleries between platelets. Constitutive equations are developed for moisture diffusion through and the elastoplastic behavior of a nano-composite. Adjustable parameters in these relations are found by fitting the experimental data. Fair agreement is demonstrated between the observations and the results of numerical simulation. A striking similarity is revealed among changes in diffusivity, ultimate water uptake, and the rate of plastic flow with an increased clay content.

Original languageEnglish
Pages (from-to)476-492
Number of pages17
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume41
Issue number5
DOIs
StatePublished - 1 Mar 2003
Externally publishedYes

Keywords

  • Diffusion
  • Mechanical properties
  • Nanocomposites

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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