Impregnation isotherms of hydroxybenzoic acid on PMMA in supercritical carbon dioxide.pdf

J. of Supercritical Fluids 41 (2007) 164–172 Impregnation isotherms of hydroxybenzoic acid on PMMAin supercritical carbon dioxide S. Diankov a, D. Barth b, A. Vega-Gonzalez c, I. Pentchev a, P. Subra-Paternault c , ? aDepartment of Chemical Engineering, University of Chemical Technology and Metallurgy, 8, Kl. Ohridski Boulevard, So?a 1756, Bulgaria bLaboratoire de Thermodynamique des Milieux Polyphas′ es-ENSIC, Institut National Polytechnique de Lorraine, 1 rue Grandville-BP 451-54001 Nancy, France cLaboratoire d’Ing′ enierie et des Hautes Pressions (LIMHP) - CNRS, Institut Galil′ ee, Universit′ e Paris 13, 99 Avenue Jean-Baptiste Cl′ ement, 93430 Villetaneuse, France Received 15 March 2006; received in revised form 20 July 2006; accepted 10 August 2006 Abstract The use of supercritical ?uid and speci?cally carbon dioxide as carrier to in?ltrate various matrices is gaining importance. This study focuses on the impregnation of poly(methyl methacrylate) by a model drug, o-hydroxybenzoic acid ( o-HBA), using supercritical carbon dioxide (SCCO 2 ) as carrier and swelling agent, with special emphasis to equilibrium data. A stirred batch reactor equipped with sampling device was employed in order to determine the sorption isotherms with a concentration parameter independent of pressure. The impregnated amount of HBA/g polymer was determined at 40 ?Cand 12, 16 and 20 MPa for concentra