Cork processing with supercritical carbon dioxide: Impregnation and sorption studies

The present study relates to the use of supercritical carbon dioxide (SCCO2) to modify the properties of cork by incorporation of new molecules. The impact of SCCO2 processing on the morphology and on the mechanical properties was found to be negligible. The impregnation of disperse blue 14 (blue dye) on cubic shaped cork samples of 5 mm occurs progressively,is dependent of the processing conditions and of the presence of lenticels and growth rings. The impregnation of the samples bulk was achieved with processing at 10 MPa and 313 K for 16h. The solubility and sorption of SCCO2 in the cork matrix was measured using circular discs and the diffusion coefficients calculated to be on the order of 10(-8) cm(2)/s, the same order as for wood materials. This work demonstrates the feasibility of supercritical fluid technology to impart new features to cork, which may lead to innovative architectural, outdoor and industrial applications. (C) 2015 Elsevier B.V. All rights reserved.