Study on the effect of spinning conditions on the performance of PSf/PVP ultrafiltration hollow fiber membrane

Abstract

Asymmetric, porous ultrafiltration polysulfone (PSf) hollow fiber membranes were fabricated via the dry-wet phase inversion spinning technique specifically for haemodialysis membrane. The objective was to discover the suitable spinning condition for the fabrication of ultrafiltration hollow fiber membrane with desired sponge-like structure. During haemodialysis procedure, uremic toxins such as urea and creatinine range from size 10,000-55,000 Da needs to be excreted out from the blood. While, proteins such as albumin (66,000 Da) need to be retained. The physical structure or morphology of a fabricated membrane is a major concern in determining the efficiency of a dialysis membrane. Different type of membrane morphology will give a different result in term of its permeability and clearance efficiency. The phase inversion spinning technique is suitable in producing ultrafiltation (UF) membrane where the average pore size of the fabricated membrane is in the range of 0.001 – 0.1 µm. However, there is many factors need to be controlled and manipulated in the phase inversion technique. In this study, the effect of the PVP on membrane pore size and performances were analysed. The contact angle measurement was measured to determine the hydrophilicity of the fibers. The hydrophilic polymer is favorable to avoid fouling and increase its biocompatibility. Furthermore, the diameter of the hollow fibers was determined using a scanning electron microscope (SEM). The effects of different morphology of the hollow fibers on the performance of the membranes were evaluated by pure water flux and BSA rejection. Both techniques were tested using permeation flux system. Based on the results obtained, it is found that the finger-like macrovoids in PSf hollow fiber membranes were suppressed by adding 8% PVP (Mw of 360 kDa) into the spinning dope solution as the result of a drastic increase in dope viscosity. On top of that, fiber spun with 8% PVP show more porous structure which contribute to higher permeability of the membrane. The result of this study can benefit to the membrane field of research especially in membrane technology for haemodialysis application.