Study On The Poly(Phthalazinone Ether Sulfone) Ultrafiltation Membrane

Poly(phthalazinone ether sulfone) (PPES) is a novel material for ultrafiltrationmembrane with high glass-transition temperature, good solubility, well membrane-formingability, good mechanical performance and chemical stability.The phase separation behavior of different nonsolvent additives in PPES casting solutionis studied according to the linerized cloud point(LCP) correlation. It is found that the phaseseparation behavior of PPES casting system, PPES/NMP/NSA, all agree with the LCPcorrelation. The binodal lines of the ternary systems are calculated according to the LCPcorrelation. Therefore, the maximum content of NSA in the casting solution can becalculated according to the binodal lines of the system. It can be concluded that thecoagulation ability of the nonsolvent additives increase as follows: water＞methanol＞glycol＞glycerol＞ethanol＞propylene glycol＞propanol＞acetic acid＞ether＞propanoic acid＞acetone＞ethylene glycol methyl ether＞butanone.The different nonsolvent additives having effects on the intrinsic viscosity of PPEScasting solution are also examined. The effect of different nonsolvent additives on theintrinsic viscosity of PPES casting solution are also examined. The results show the influenceof additives to the intrinsic viscosity follow the sequence as: H₂O＞propanol＞propanoic acid＞ethylene glycol methyl ether＞butanone. And the intrinsic viscosity decrease with theincrease of the additives content.Ultrafiltration membranes are prepared successfully from poly(phthalazinone ethersulfone)(PPES) with a dry/wet phase inversion technique. Organic substances are used asnonsolvent additives, and N-methyl-2-pyrrolidone(NMP) is used as a solvent in membranepreparation. The type and concentration of NSA in casting solution on the morphology andperformance of ultrafiltration membranes are systematically investigated. A series of PPESultrafiltration membranes with different morphology(finger-type or sponge-like) andperformance have been successfully prepared. The properties of ultrafiltration membranesshow that the PEG2000-20000 could be removed and the pure water flux range from 49L·m^-2·h^-1 to 602 L·m^-2·h^-1 under the operating pressure of 0.1 MPa.The influences of total polymer concentration, coagulation temperature, evaporationtime on the performance of ultrafiltration membrane are also examined, the results show thatwith the increase of total polymer concentration, the pure water flux decreases and therejection increases accordingly; as the increase of coagulation temperature, the pure water flux decreases and the rejection increases; with the increase of the evaporation time, the purewater flux firstly increases then decreases slightly and the rejection decreases. Theexperiments show that the membranes still has good performances when the temperature offeed solution was raised to 90℃, it proves that the membranes had excellent heat-resistance.