The influence of solvent properties on the performance of polysulfone/[beta]-cyclodextrin polyurethane mixed-matrix membranes

This study investigates the effect of solvent properties on the structural morphology and permeation properties of polysulfone/[beta]-cyclodextrin polyurethane (PSf/[beta]-CDPU) mixed-matrix membranes (MMMs). The membranes were prepared by a modified phase-inversion route using four different casting solvents [dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), dimethyl acetamide (DMA), and N-methyl-2-pyrrolidone (NMP)]. While DMSO-based membranes demonstrated particularly high permeability (ca 147 L/m2h.bar), their crystallinity was low compared to MMMs prepared using DMA, DMF and NMP due to the formation of thin active layers on their surfaces. Cross-sectional morphology revealed that the MMMs have a dense top skin with finger-like inner pore structures. Membranes prepared using NMP displayed the highest hydrophilicity, porosity, and crystallinity due to the low volatility of NMP; DMF membranes exhibited superior mechanical and thermal stability due to its (DMF) high hydrogen bonding ([delta]H) values. Thus, the morphological parameters, bulk porosity, and flux performance of MMMs have a significant inter-relationship with the solubility properties of each solvent (i.e., [delta]H, density, volatility, solubility parameter). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2005-2014, 2013 [PUBLICATION ABSTRACT]