Effect of Bore Fluid Conditions on Structures and Properties of Poly(m-phenylene isophthalamide) Hollow Fiber Membranes

This study investigates the effects of bore fluid composition on the morphological characterization, mechanical properties, and membrane performance of poly(m-phenylene isophthalamide) (PMIA) hollow fiber membranes prepared by a dry-jet wet spinning method using a non-solvent induced phase separation (NIPS), as an attempt to manufacture and apply high-performance membranes. Scanning electron microscopy (SEM) analysis reveals that the addition of DMAc (or NMP) to the internal coagulant (bore fluid) based on deionized water induces a transition from finger-like to sponge-like pore structures in the final PMIA membranes. Mechanical properties analysis shows an increase in tensile strength and a decrease in elongation at break as the additive content in the bore fluid increases. Water permeability and rejection analysis present a trade-off trends, with higher additive content leading to reduced water permeability and increased rejection. In other words, despite the consistent changes observed in pore structure with changes in additive type and content in the bore fluid, achieving an optimal balance between high water permeability and low rejection remains a challenge through these structural control and changes. Therefore, for the development and application of high-performance PMIA-based hollow fiber membranes, it is necessary to control and optimize the pore structure of the final PMIA membrane through extensive research on various process parameters.