The flat sheet nitro cellulose (CN)-cellulose acetate (CA) blended membranes were prepared via phase-inversion method from the casting solutions composed of CN-CA blended polymers and acetone-formic acid mixed solvents. Several membrane preparation parameters were introduced on the membrane fabrication process, and their effects on the morphology and performance of resulting membrane were investigated. The membranes obtained had asymmetric structure composed of an extremely thin dense surface layer (skin layer) on the top of a relatively porous substructure with sponge or finger-type. Finger-type structure was obtained in a membrane prepared with only CN. Sponge-type structure appeared in a membrane prepared with CN and CA. With the increase of the solvent evaporation period for the cast film up to about 2 minutes, water permeability (water flux) was decreased. and then increased with the evaporation period afterwards. On the other hand, solute retention showed opposite result which was an initial increase followed by a decrease with the increasing solvent evaporation periods. NA(5,5) -0.5 membrane had the molecular weight cut-offs more than 10,000. From the result of NA(6,6) membranes, it was suggested that it would be possible to fabricate a membrane capable of effectively repenting a sort of materials with the molecular weight of thousand unit.

Nitrocellulose (CN)-Cellulose acetate (CA) 혼합막의 한외여과막으로서의 막설계지침을 확립하려는 목적으로, 본 연구에서는 CN-CA blended polymer와 acetone-formic acid mixed solvent로 조성된 제막용액으로부터 상전환법에 의해 평판형 막을 만들어, polymer 농도 및 조성, 용매증발시간 등에 의한 막의 구조변화와 수 투과유속(투과량) 및 용질배제율을 조사, 검토하였다. 생성된 막은 비대칭구조로서 치밀한 표면층과 지상 혹은 스폰지상의 허술한 내부층으로 구성되어 있었다. CN막의 내부층에는 지상구조가 형성되었으며, 반면에 CN-CA 혼합막은 스폰지상 구조로 이루어져 있었다. 수 투과유속은 용매증발시간 2분까지는 시간에 따라 감소하였으나, 3분이후 부터는 다시 증가하였다. 한편 용질배제율의 결과는 수 투과유속과 반대의 경향을 보였다. NA(5,5)-0.5 막의 분자량 분획성은 1만이었고, 한편 NA(6,6) 막을 사용하면 천단위의 분자량 분획성을 갖는 막의 제조가 가능함이 제시되었다.