Evaluation of the gas transfer characteristics of porous copolyurethane oxygenator membranes.

Porous copolyurethane membranes were prepared by solvent casting thin polymer films onto fibrous substrates. Pore size, water filtration rates, and gas transmission rates were measured to determine the influence of substrate, polymer type, and coating thickness on the membrane properties in the dry and wet state. Cellulosic substrates were not as satisfactory as were polyethylene, polyester, or nylon substrates. Porous membranes formed on these latter substrates had gas transfer rates similar to silicone rubber membranes. Although O2 transfer was similar to Gore-Tex and Celgard, CO2 transfer was less, apparently due to fewer pores in the copolyurethane membranes and possible wetting of the pores by water.