Formation of Hollow Fiber Membranes via TIPS

University Of Texas At Austin, Austin TX

Investigators

Abstract

CTS-0004534 Douglas R. Lloyd University of Texas ABSTRACT Polymeric membranes in flat sheet and hollow fiber form are the basis of many industrial separation processes. The advantages of the hollow fiber geometry in membrane processes are well documented in the literature. Traditionally, phase inversion techniques have been used to make the hollow fibers from glassy polymers. In 1981, the thermally induced phase separation (TIPS) method for making flat sheet membranes was introduced. TIPS allows the production of high performance membranes from a broader range of polymeric materials that offer performance advantages over phase inversion membranes for certain applications because of greater thermal and chemical stability. For example, potential applications include separations involving of strong organic solvents and high concentrations other harsh chemicals, separations involving elevated temperatures, purification of etching solutions in the micro-electronics industry, lactic acid recovery in the food industry, and separation of toxic pollutants, pharmaceutics, and fermentation products, as well as membrane distillation. In many of these membrane applications, it is essential to have an anisotropic membrane with well controlled pore structure. The objective of the proposed research is to provide the requisite fundamental knowledge necessary to control porous structure in anisotropic, microporous, hollow fiber membranes produced via TIPS. This research project constitutes a systematic and fundamental study to characterize and model the impact of system physical properties and processing parameters on the processability, microscopic and macroscopic structure, and performance of hollow fiber membranes formed via the TIPS process. Through a balance of modeling and experiments, this research is generating the fundamental knowledge needed to control the concentration and temperature gradients in the homogeneous solution and to develop the process for the formation of anisotropic hollow fibers on a laboratory scale. A fully coupled heat-, mass-, and momentum-transfer model for predicting the temperature, concentration and velocity profiles within the nascent membrane at the time of phase separation and surface pore size after quenching is being devised.