【作者】 张正华；

【导师】 安全福；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2011， 硕士

【摘要】 本文针对聚合物超滤膜在较高压力下应用时很容易被压密的现象,通过调控铸膜液性质,制备系列密度梯度分布海绵状结构、耐压性好和通量高的聚砜(PSF)超滤膜。首先,设计粘度可调控的PSF/DMAC和PSF/DMAC/PVP共8个不同体系。通过研究铸膜液的粘度和浊点,相分离过程的光透实验,膜的表面和断面形貌,膜孔径、孔隙率及水通量等,发现对于由溶液相转化法制备得到的聚砜超滤膜而言,铸膜液的零切粘度是影响膜形貌、结构与通量的重要因素之一。其次,设计PSF/DMAC/PVP, PSF/DMAC/Ethanol和PSF/DMAC/Ethanol/PVP共12个不同添加剂含量的体系。通过研究膜的水通量,表面和断面形貌,耐压稳定性,膜耐压前后孔隙率的变化等,发挥PVP和乙醇对铸膜液的共同调控作用,得到了密度梯度分布海绵状结构、耐压性好和通量高的PSF超滤膜。最后,通过分散聚合法合成了系列不同单体组成比例的SiO2-PAMPS纳米粒子,并以SiO2-PAMPS为添加剂,制备PSF杂化超滤膜。通过考察杂化膜的水通量,孔径和孔隙率,表面和断面形貌,力学性能,耐压稳定性及杂化膜振荡前后的接触角等,发现SiO2-PAMPS纳米粒子在杂化膜表面非常稳定,杂化膜的水通量,力学性能,耐压性能明显提高。由PSF/DMAC/Ehanol/SiO2-PAMPS4(单体的摩尔比(MSiO2/MPAMPS)为15.3：1,浓度为0.3 wt%)体系所得的杂化膜,纯水通量在0.1 MPa为190 L/m2.h,拉伸强度和断裂伸长率分别为4.3 MPa和20.5%,断面结构在0.5 MPa下连续操作4h,没有压密现象发生。更多还原

【Abstract】 The polymeric ultrafiltration membranes are easily compacted during the filtration applications under a relatively high pressure. In this work, polysulfone (PSF) ultrafiltration membranes with a density gradient of the sponge-like cross-section structure were prepared via the solution phase inversion process by controlling the properties of casting solution. These membranes have the good compressive strength and the high water flux.Firstly, in terms of effect of zero shear viscosity of the casting solution on the morphology and permeability of polysulfone ultrafiltration membranes, two systems were designed:the PSF/DMAC binary system and PSF/DMAC/PVP ternary system in which the viscosity was dominated by changing the concentration of PSF and the molecular weight of PVP, respectively. By measuring the viscosity and the cloud point of casting solutions, the phase-separation process, surface and cross morphologies, pore size and porosity and the water flux of membranes, it was found that the zero shear viscosity of casting solutions was one of the most important parameters for the morphology and permeability of polysulfone membranes.Secondly, in terms of fabrication of polysulfone ultrafiltration membranes of a density gradient cross section with a good compressive strength, three different kinds of systems including PSF/DMAC/PVP, PSF/DMAC/Ethanol ternary systems and PSF/DMAC/Ethanol/PVP quaternary system were used as casting solutions. By measuring the water flux, surface and cross morphology, the anti-pressure stability, the variation of the pore volumes between the fresh and pressurized membranes, it was found that the PSF ultrafiltration membrane with a density distribution structure possessing a good compressive strength and a relatively high water flux could be prepared by using PVP and ethanol together in PSF/DMAC/Ethanol/PVP solution.Lastly, in terms of influence of nano-sized SiO2-PAMPS fillers on the morphology and property of PSF ultrafiltration membranes, the different monomer ratios of SiO2-PAMPS nanoparticles were prepared by dispersion polymerization and then were used to fabricate the novel SiO2-PAMPS/PSF hybird ultrafitration membranes. By measuring the pure water flux, the porosity and the pore size, the surface and cross morphology, the stretching test, the compressive strength test and the water contact angles (before and after shaking) of membranes, it was found that the SiO2-PAMPS nanoparticles were excellently stable on the membrane surface. Meanwhile, the water flux, the mechanical property and the compressive strength of hybrid membranes were significantly improved. The hybrid membrane prepared by the PSF/DMAC/Ehanol/SiO2-PAMPS4 (the monomer mol ratio (MSiO2/MPAMPS) is 15.3:1, and the concentration of the nanoparticles is 0.3 wt%) casting solution had the water flux of 190 L/m2.h under 0.1 MPa, the tensile strength of 4.3 MPa, the breaking elongation of 20.5%, and the cross section of which was greatly stable even under the continuous operation with 0.5 MPa.更多还原