The interaction of supercritical carbon dioxide (scCO(2)) with poly(vinyl chloride) (PVC) was systematically investigated. PVC films of 0.5 mm thickness were treated with CO2 at pressures between 5 and 40 MPa, at temperatures between 40 and 70 degreesC and soaking times between 0.5 and 7 h. The gravimetric desorption data were kinetically and thermodynamically evaluated assuming Fickian diffusion and the morphology changes due to the CO2 treatment investigated by microscopic methods. The sorbed amount of CO2, q (q = g(CO2)/g(polymer)) ranged between 0.03 (5 MPa, 70 degreesC) and 0.13 (15 MPa, 40 degreesC). The desorption diffusivities, D-d, were in the order of 0.1 x 10(-11) m(2)/s and decreased with decreasing amounts of CO2. In contrast, the sorption diffusivities, D-d, were markedly higher and varied between 0.7 x 10(-11) and 2.5 x 10(-11) m(2)/s (20 MPa, 40-70 degreesC). The CO2 treatment changed the polymer chain structure. macroscopically visualized by the film opaqueness and by the density decrease to 1.05 g/cm(3). Microcellular structures were not detected. (C) 2001 Elsevier Science B.V. All rights reserved.