Preparation, Morphologies, and Properties of Positively Charged Quaternized Poly(phthalazinone ether sulfone ketone) Nanofiltration Membranes

Positively charged quaternized poly(phthalazinone ether sulfone ketone) (QAPPESK) nanofiltration (NF) membranes were prepared from chloromethylated poly(phthalazinone ether sulfone ketone) by the dye/wet phase inversion method with N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc) as solvents. The effects of the ratio of NMP to DMAc, the evaporation time, the evaporation temperature, and the coagulation temperature on membrane performance were evaluated by the orthogonal design method. The results showed that the optimal preparation conditions were an NMP/DMAc ratio of 2/8, an evaporation time of 5 min at 70 degrees C, and a coagulation temperature lower than 5 degrees C. The effects of the additive type and concentration on the QAPPESK NF membrane cross-section morphology and performance were investigated in detail. Furthermore, QAPPESK NF membranes exhibited good thermal stability with stable membrane performance for 120 h at 60 degrees C. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 1389-1397, 2009