Preparation and characterization of novel solvent-resistant nanofiltration composite membranes based on crosslinked polyurethanes

In several innovative application fields, there is an increasing requirement for solvent-resistant nanofiltration (SRNF) membranes. In this work, an innovative SRNF membrane is presented: the thin selective layer is composed of cross-linked polyurethane cast on an ultrafiltration (UF) membrane, which is composed of a stable polymeric material. The thin selective layer is produced via simultaneous in situ polymerization and casting on the UF support. After both the UF and NF composite membranes have been characterized through chemical and physical analyses, the NF membranes are tested: the permeate fluxes and the rejection of test substance (4',5'-dinitrofluorescein) have been measured with four different organic solvents. The solvent transport through the novel SRNF membranes is discussed by introducing a new variable, the normalized flux, obtaining a satisfying predictive model.