Mechanical Properties of Cork : Effect of Hydration

Abstract : The alveolar structure of cork confers to this natural material specific physical properties such as low permeability to liquids and gases, thermal and acoustic insulation, high elasticity. These properties make this material particularly interesting for sealing wine. We focused in this study on the compression properties of cork along the radial and tangential direction at 25°C when cork is stored in various relative humidity environments, from 0% to 100%. The direction of compression significantly affected the Young’s modulus, with a higher value for the radial direction. More surprising is the effect of water sorption on its mechanical property. Both directions exhibit the same behavior when the relative humidity is increasing. First the Young’s modulus is constant up to 50% relative humidity. Then above this point, the increase in water content leads to a decrease in material rigidity which is attributed to water clusters formations.