Synthesis, characterization and separation properties of novel PU membranes crosslinked by β-cyclodextrin

Abstract

Abstract Polyurethane (PU) pervaporation (PV) membranes are promising for the recovery of phenol from water. The four kinds of PU membranes, with hydroxyl terminated polybutadiene (HTPB) as a soft segment and diamine or β-cyclodextrin (CD) as a chain extender, were prepared. The structures and properties of these membranes were characterized by means of Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle. Furthermore, the PV performances were investigated for separating phenol/water mixtures at different temperatures. The results showed that CD increased the permeability and selectivity of PU, at the same time. At 80°C, the total fluxes of pure PU membranes with HTPB (Mn=2500 g/mol) (H2500) and with HTPB (Mn=2000 g/mol) (H2000) were 6.96 kg μm m-2 h-1 and 6.09 kg μm m-2 h-1, respectively, while those of PU membranes containing CD with HTPB (Mn=2500 g/mol) (H2500-CD) and with HTPB (Mn=2000 g/mol) (H2000-CD) were 9.16 kg μm m-2 h-1 (increased by 31%) and 8.23 kg μm m-2 h-1 (increased by 26%), respectively. The separation factors of H2500 and H2000 were 23 and 34, while those of H2500-CD and H2000-CD were 33 (increased by 43%) and 40 (increased by 9%). Additionally, the modification of CD crosslinking was simple and easy with less modifying agent.