Abstract
Adosorption isotherms of dialysis membranes were determined by the BET method, calculating the amount of adsorbed nitrogen and equilibrium pressure. From those isotherms the membrane pore diameter distribution was calculated by the Inkley method, The pore diameter distribution of vacuum-dried membranes and freeze-dried membranes were obtained by the BET method, Pore volume of freeze-dried membranes was higher than that of vacuum-dried membranes. Freeze-drying is well suited to obtain the same pore volume as wet membranes that are used clinically, A contraction in fiber length and wall thickness may occur on drying, and the rate of the contraction depends on material, water content and surface porosities. Pore diameter distributions of dialysis membranes were also determined by the DSC method, Results were nearly the same as those by the BET method, The DSC method also allows determination of the pore diameter distribution. Permeabilities for Beta-2-microglobulin and pure water were found to increase with the pore volume.
