Journal article

Cellulose whisker/epoxy resin nanocomposites

  • Tang, Liming Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, USA
  • Weder, Christoph Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, USA - Adolphe Merkle Institute and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Published in:
  • ACS Applied Materials and Interfaces. - 2010, vol. 2, no. 4, p. 1073-1080
English New nanocomposites composed of cellulose nanofibers or “whiskers” and an epoxy resin were prepared. Cellulose whiskers with aspect ratios of ∼10 and ∼84 were isolated from cotton and sea animals called tunicates, respectively. Suspensions of these whiskers in dimethylformamide were combined with an oligomeric difunctional diglycidyl ether of bisphenol A with an epoxide equivalent weight of 185−192 and a diethyl toluenediamine-based curing agent. Thin films were produced by casting these mixtures and subsequent curing. The whisker content was systematically varied between 4 and 24% v/v. Electron microscopy studies suggest that the whiskers are evenly dispersed within the epoxy matrix. Dynamic mechanical thermoanalysis revealed that the glass transition temperature (Tg) of the materials was not significantly influenced by the incorporation of the cellulose filler. Between room temperature and 150 °C, i.e., below Tg, the tensile storage moduli (E′) of the nanocomposites increased modestly, for example from 1.6 GPa for the neat polymer to 4.9 and 3.6 GPa for nanocomposites comprising 16% v/v tunicate or cotton whiskers. The relative reinforcement was more significant at 185 °C (i.e., above Tg), where E′ was increased from ∼16 MPa (neat polymer) to ∼1.6 GPa (tunicate) or ∼215 MPa (cotton). The mechanical properties of the new materials are well-described by the percolation model and are the result of the formation of a percolating whisker network in which stress transfer is facilitated by strong interactions between the whiskers.
Faculté des sciences
Adolphe Merkle Institute
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