Preparation and characterization of polyacrylonitrile-based membranes: Effects of internal coagulant on poly(acrylonitrileco-maleic acid) ultrafiltration hollow fiber membranes

Ultrafiltration hollow-fiber membranes (UHFMs) of poly(acrylonitrile-co-maleic acid) (PANCMA) were prepared by a dry-wet phase inversion process. The morphologies of inner surface and cross section for these hollow fibers were inspected with scanning electron microscopy. It was found that, by increasing the amount of solvent DMSO in internal coagulant, the number and size of macrovoid underneath the inner surface decreased. The water flux of the UHFMs also decreased while the bovine serum albumin rejection increased minutely. These results were interpreted based on the ternary phase diagrams for the PANCMA/DMSO/(H2O+DMSO) system, which was obtained from the experimental cloud point measurements and empirical linearized cloud point relation. It was envisaged that the membrane surface could be further modified by the reaction of acid groups with poly(ethylene glycol).

Ultrafiltration hollow-fiber membranes containing reactive acid groups were manufactured from poly(acrylonitrile-co-maleic acid) with a dry-wet phase inversion process. The structures, especially the size and number of the macrovoids in the sub-layer, and the properties of the membranes could be changed by the addition of DMSO in the internal coagulant. Further work concerning the reaction of the reactive groups on membrane surfaces with poly(ethylene glycol) and/or amino sugars to improve the antifouling and biocompatible performances will be described in a forthcoming paper.