| abstract |
The present invention discloses a hydrophobic poly(4-methyl-1-pentene) hollow fiber membrane for retaining anesthetics, which has an inner surface and an outer surface and a spongy, open-cell membrane between the inner surface and the outer surface. A substantially isotropic support layer of the microporous structure without macrovoids, and a dense separation layer having a thickness between 1.0 μm and 3.5 μm adjacent to the support layer on the outer surface. The membrane has a porosity in the range of greater than 35 vol% to less than 50 vol% and a CO2 permeability of 20 mol/(h·m 2 ·bar) to 60 mol/(h·m 2 ·bar), a gas separation of at least 5 Factor alpha (CO 2 /N 2 ) and a selective CO 2 /anaesthetic of at least 150. The method for preparing the membrane is based on a thermally induced phase separation method in which a homogeneous solution of poly(4-methyl-1-pentene) in a solvent system comprising components A and B is formed, Among the polymer components, component A is a strong solvent and component B is a weak non-solvent. After forming the hollow fibers, the hollow fibers are cooled in a liquid cooling medium to form hollow fiber membranes. The concentration of the polymer component in the solution may be in the range of 42.5% to 45.8% by weight, and the hollow fibers exiting the die pass through the gap between the die and the cooling medium, wherein the gap length is in the range of 5mm to 30mm Inside. |