Research Of The Preparation And Modification Of PVC/PPSU Blend Membrane

Membrane separation is a new and efficient separation technology,it has attracted muchattention for its advantages of high separation efficiency,no secondary pollution and low energyconsumption. But during the actual project operation,memrane’s easily contamination, membranecleaning and replacation, high energy costs lead to membrane separation technology has not beenextensively used for sewage treatment. Polyvinyl chloride (PVC) is the the second largestsynthetic material with the advantages of cheap, good chemical stability, good mechanicalproperties,etc.It cause the extensive concern in the field of the development of new membranematerials. But studies had shown that PVC is hydrophobic, so it easily lead to membrane fouling,and only when PVC has a high percentage of quality, PVC membrane will have a higher strength,but at the same time the water flux of PVC membrane will be a sharp decline, even it’s zero;furthermore, PVC has a disadvantage of poor membrane-forming properties. Therefore as amembrane material, PVC needs for modification. Polyphenylene sulfone (PPSU) is a novelmembrane material, it has a better toughness, impact resistance, hydrolytic stability, and morestable chemical properties and good mechanical properties than other polymers, but it’s moreexpensive.Therefore blending PPSU with PVC,it’s expected to develop a greater flux, strongmechanical performance, low price of new membrane materials.In this study, PVC/PPSU blend memrane was prepared using solution blending method.First,the compatibility of PVC/PPSU blend membranes was characterized by shear viscosity methodand Fourier transform infrared spectroscopy (FTIR); then by discussing the SEM cross-sectionaland surface images of PVC/PPSU blend membranes and blends properties of the membrane (waterflux, anti-tensile strength, hydrophilicity and stain resistance) with different blend ratios, theoptimum blending ratio was determined. On the basis of the optimum blending ratio, the effects ofdifferent polymer contents on the PVC/PPSU blend membrane performance were explored.Considering that the PVC and PPSU are all hydrophobic materials, adding different hydrophilicpolymers (PAN, PVB), small inorganic molecule SiO2and modified substance PVP-g-SiO2 separately for PVC/PPSU blend membrane’s hydrophilic modification was carried out. Theconclusions obtained by the research are as follows:1. The results of PVC/PPSU blend solution shear viscosity and infrared spectroscopy (FTIR)analysis showed that the PVC/PPSU blend system was partially compatible system.2. By exploring the effects of blending ratio, polymer concentration on the PVC/PPSUblend membrane’s microstructure and overall performance, the results show that when the blendratio is5/5and the polymer content is20%, PVC/PPSU blend membrane will have the bestperformance.3. Hydrophilic polymer PAN, PVB for PVC/PPSU blend membrane hydrophilicmodification results show that, the influence of PAN on PVC/PPSU blend membrane’shydrophilic modification is better, and the optimal dosage is30percentage of the total mass of thepolymer.4.The results of the effects of small molecules SiO2and inorganic modified substancesPVP-g-SiO2on PVC/PPSU blend membrane’s hydrophilic modification show that when SiO2’sconcentration of the casting solution is1%,the performance of PVC/PPSU blend membrane’shydrophilic and antifouling has been greatly improved;while the optimal dosage of PVP-g-SiO2is3%, and the effects of the modification is better than SiO2. Comparing the results of PAN to PVC/PPSU blend membrane’s modification with the influence of inorganic small substances SiO2andinorganic modified substances PVP-g-SiO2on PVC/PPSU blend membrane’s modification, theresult is that when the additive is PVP-g-SiO2, PVC/PPSU blend membrane shows the bestmodification performance.