Preparation of annular hollow fibre membranes

Preparation of an annular hollow fibre membrane using a triple-orifice spin neret was studied. Various annular hollow fibre membranes were prepared fro m different membrane forming systems. The polymers used in spinning the ann ular hollow fibres include polysulfone (PSf), polyethersulfone (PESf), poly etherimide (PEI) and cellulose acetate butyrate (CAB). The solvents are N-m ethyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAC). The additives are w ater and ethanol. The spinning conditions to form annular hollow fibres wer e investigated experimentally. Structures of the annular hollow fibres were examined by scanning electron microscopy. Through the proper selection of polymers, solvent and additives, and polymer dope composition, the annular hollow fibres can be formed with controlled width of the hollow fibre annul us. (C)2000 Elsevier Science B.V. All rights reserved.