Novel preparation and fundamental characterization of polyamide 6 self-supporting hollow fiber membranes via thermally induced phase separation (TIPS)

Abstract

Polyamide 6 hollow fiber membranes were successfully fabricated via a thermally induced phase separation (TIPS) method for the first time to the best of our knowledge. Dimethyl sulfone (DMSO2) and sulfolane were used as diluents for the TIPS method. Also, poly(ethylene glycol) 200, 300, and 400 and 1,3-butanediol were used as bore solutions to control the pores of the selective layer in the lumen side. Furthermore, propylene glycol was used as a mixing component in quenching bath to generate large pores on the outer surface of the hollow fiber membrane. The effects of polymer concentration, diluent, bore solution, and quenching bath on the morphologies, water permeabilities, and mechanical properties of the polyamide 6 hollow fiber membranes were systematically investigated. The relationship between water permeability, mechanical properties, and spinning conditions was discussed in detail. It was observed that all membranes fabricated under different spinning conditions had interconnected and bicontinuous structures through liquid-liquid phase separation. It was also shown that the novel developed polyamide 6 hollow fiber membranes had suitable water permeabilities and good mechanical properties for the tough separation processes in various industries.