Sorption kinetics and equilibria for CO2 in polycarbonate were studied over a range of temperatures from 35° to 65°C and pressures from 3 to 22 atm. The dual mode sorption model of Vieth et al. was used to test the data, and a comparison was made with previous work on glassy polystyrene. Further evidence of the validity of generality of the model in providing a consistent picture of small-molecule diffusion in glassy polymers was thereby provided. The technical feasibility of membrane separation of H2 from a H2/CO2 mixture by selective permeation through polycarbonate was examined at 50°C.