Morphology and Mechanical Properties of a New Nanocrystalline Cellulose/Polysulfone Composite Membrane

A new nanocrystalline cellulose/polysulfone composite membrane was prepared. The composite membranes were coagulated in different coagulation baths (i.e., water, methanol, ethanol, isopropanol) and concentrations (i.e., 10, 30, 50 v/v%). The chemical structure of membrane is characterized by Fourier transform infrared spectroscopy. The viscosity of the casting solutions was measured. The cross-section morphology of the membrane was characterized using scanning electron microscopy. The mechanical properties were also studied. Results showed that the connectivity of nanocrystalline/polysulfone composite membrane pores is better than that of pure polysulfone membrane, macrovoids, and short finger-like pores are produced when adding methanol, ethanol, or isopropanol into the coagulation bath. As the coagulant concentration increases, the sponge-like structure becomes looser and thinner. A right amount of nanocrystalline cellulose has a positive effect on the tensile strength. The tensile strength of the pure membrane in different coagulation baths shows the following order: methanol > ethanol > isopropanol > water (10% v/v).