Research On The Preparation And Properties Of The Dialysis Composite Membrane Modified With Nanocelluloses

Nanocelluloses were prepared with chemical and physical method. Also the morphology, crystal structure, and thermal stability of the nanocelluloses were evaluated by transmission electron microscopy, scanning probe electron microscope, X-diffraction, and thermo gravimetric analyzer. On this basis, the dialysis composite membrane modified with nanocelluloses was prepared by phase inversion process. The mimic liquid, with the composition of bovine serum albumin, lysozyme and urea, was made in order to test the penetrability, rejection ratio, and clearance of the composite membrane. According to the analysis of the influencing factors for preparation and the result of the orthogonal test, the optimal conditions were obtained:nanocelluloses contents was 0.3%, polysulfone contents was 18%, additive PEG (molecular weight is 1000) contents is 3%, N, N-dimethylacetamide was chosen for the solvent, the temperature of the coagulation bath (water) was 25℃.With the testing results of the casting solution viscosity, tensile strength and elongation ratio of the dialysis composite membrane, the influencing indicators for mechanical properties were measured. It was indicated that the mechanical properties were improved by adding nanocelluloses. Also the PS contents and the temperature of the coagulation bath also took an important role for that.Under the premise of the performance improvement, the pore structures of the dialysis membrane were tested in detail. The porosity and average pore size were measured and calculated with different indicators of the dialysis membrane. Depend on the scanning electron microscope and scanning probe microscopy, the internal and external structures of the dialysis membrane were observed. The result showed that the composite membrane has a typical asymmetric structure with the dense epidermis. The support layer displayed finger-like porous structures with good connectivity.The dialysis membrane was also evaluated by contact angle and moisture contents, which reflected the hydrophilicity of the membrane. With the measurement of the flux attenuation, protein adsorption, and reuse conditions of the dialysis membrane, the anti-pollution performance was evaluated. The results showed that nanocelluloses significantly increased the hydrophilicity of the dialysis membrane, and thus improved its anti-pollution performance.Finally, other properties of the dialysis membrane were test by X-diffraction, thermo gravimetric analysis and infrared spectroscopy. Overall, with the addition of nanocelluloses, the permeation properties, mechanical properties, hydrophilicity, anti-pollution performance of the dialysis composite membrane were improved obviously.