Measurement of CO2 solubility and diffusivity in poly(L-lactide) and poly(D,L-lactide-co-glycolide) by magnetic suspension balance

The solubility of supercritical carbon dioxide (scCO(2)) in poly(L-lactide) and poly(D,L-lactide-co-glycolide) at different temperatures (308, 313 and 323 K) and pressures (10-30 MPa) was measured using a magnetic suspension balance. The solubility data were also used for estimating the binary diffusion coefficients. The results show a good solubility of CO2 in both polymers: up to 43% in poly(L-lactide) and 30% in poly(D,L-lactide-co-glycolide). The diffusion coefficients have high values, which verify the liquid-like solvating properties of scCO(2). The diffusion coefficient depends on the quantity of gas already absorbed by the polymer; its values decrease with increasing gas concentration. (C) 2008 Elsevier B.V. All rights reserved.