Preparation Of Integrated And Asymmetric Polyamide Membranes In Pervaporation With Compact Surface

Some contents are discussed for the purpose of preparation of integrated and asymmetric polyamide membranes in pervaporation with compact surface.The polyamide membranes were prepared by using a novel ODPB-BAPP condensation polymer as the membrane material; N-methyl pyrrolidone was selected as the major solvent depending on the data of both solubility parameter and casting solution viscosity; The volatile solvents, such as tetrahydrofuan, acetone and ether, were added respectively in the coating solution as the co-solvents.Discuss their infection on casting solution viscosity, evaporation kinetics, phase separation times, gelation rate and structure and performance of membranes;Water,ethanol, propanol, isopropanol, butanol and pentanol were used as the gelation media, respectively. Discuss their infection on phase separation times, gelation rate and structure and performance of membranes;The experiments indicate that :N-methyl pyrrolidone is the best solvent for the polyamide made by ODPB-BAPP;The lower boil leads to better volatility, more phase separation times, slower gelation rate and is propitious to compact surface;The gelation rates were measured by a set of gelation kinetics measurement system with these gelation media, and the results showed that the gelation rates for different gelation media were in the order of water > ethanol > propanol > isopropanol > butanol > pentanol. The phase sepatation times for these gelation media were measured by a phase separation kinetics measurement apparatus.It is shown that finger-like membrane cross-sectional morphology results from the case of instantaneous demixing, and sponge-like membrane cross-sectional morphology results from the case of delayed demixing.The solvents with more volatility and slower gelation rate are propitious to form compactsurface...