共查询到20条相似文献,搜索用时 196 毫秒
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对聚偏氟乙烯(PVDF)/碳酸二苯酯(DPC)体系,采用热致相分离(TIPS)法制备了PVDF微孔膜.通过稀释剂的溶度参数对体系的相容性进行分析,热力学相图和不同PVDF质量浓度下制备的微孔膜断面照片均证明该体系具有较宽的液-液相分离区.PVDF/DPC体系偏晶点对应的PVDF浓度约为质量分数56%,低于此浓度体系降温后先发生液-液相分离,随着PVDF浓度的增大,微孔膜断面结构由双连续结构转变为蜂窝状结构,且膜孔孔径减小,高于此浓度体系降温后只发生固-液相分离,微孔膜断面呈块状紧密堆积结构.较快的冷却速率有利于低PVDF浓度时较小孔径膜和高PVDF浓度时较小球粒尺寸膜的生成. 相似文献
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采用热致相分离法(TIPS)制备PVDF平板和中空纤维微孔膜,研究了二元稀释剂对PVDF微孔膜的结构的影响。当二元稀释剂由邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二丁酯(DBP)、三乙酸甘油酯(GTA)中的一种,与邻苯二甲酸二辛酯(DOP)、癸二酸二丁酯(DBS)、苯甲酸苄酯(BB)中的一种混合而成时,TIPS法制备的PVDF膜的断面均具有双连续结构;当二元稀释剂由二苯甲酮(DPK),与DOP、DBS、BB中的一种混合而成时,TIPS法制备的PVDF膜的断面为胞腔结构,断面孔的孔径按如下顺序依次增大:BB、DOP、DBS。GTA/DBS为二元稀释剂,采用TIPS法制备PVDF中空纤维微孔膜,随着二元稀释剂中GTA的质量分数由30%增加至50%,膜的断面由双连续结构变为球晶结构。 相似文献
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马文中赵宇辰李玉雪张鹏贾天飞杨海存刘春林陶国良龚方红 《高分子材料科学与工程》2018,(9):139-147
以表面引发接枝聚合制备多壁碳纳米管接枝聚甲基丙烯酸甲酯(MWCNTs-g-PMMA)。通过非溶剂致相分离(NIPS)法制备聚偏氟乙烯(PVDF)/MWCNTs-g-PMMA复合微孔膜。通过差示扫描量热和衰减全反射红外光谱测试考察了微孔膜的热性能和结晶性能,通过水接触角和水通量测试分析了膜的亲水性能,通过场发射扫描电子显微镜和力学性能测试分析了膜的微观形貌和力学性能。随着MWCNTs-g-PMMA接枝率和含量的增大,PVDF复合微孔膜的结构和性能明显改善。当MWCNTs-g-PMMA接枝率和含量分别为28. 6%和1%时,PVDF复合微孔膜的亲水性能、结晶度、β相和力学性能相对纯PVDF膜提升最为明显。 相似文献
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以表面引发接枝聚合制备多壁碳纳米管接枝聚甲基丙烯酸甲酯(MWCNTs-g-PMMA)。通过非溶剂致相分离(NIPS)法制备聚偏氟乙烯(PVDF)/MWCNTs-g-PMMA复合微孔膜。通过差示扫描量热和衰减全反射红外光谱测试考察了微孔膜的热性能和结晶性能,通过水接触角和水通量测试分析了膜的亲水性能,通过场发射扫描电子显微镜和力学性能测试分析了膜的微观形貌和力学性能。随着MWCNTs-g-PMMA接枝率和含量的增大,PVDF复合微孔膜的结构和性能明显改善。当MWCNTs-g-PMMA接枝率和含量分别为28. 6%和1%时,PVDF复合微孔膜的亲水性能、结晶度、β相和力学性能相对纯PVDF膜提升最为明显。 相似文献
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采用熔体挤出拉伸法以高、低分子量混合聚偏氟乙烯(PVDF)为原料制备微孔膜,研究了不同热拉伸温度对PVDF微孔膜表面形貌及结晶行为的影响,通过扫描电子显微镜、红外光谱仪、X射线衍射仪和差示扫描量热仪等测试手段分别对微孔膜的形态、结构、晶型进行表征.结果表明,热拉伸温度对PVDF微孔膜的成孔形貌、孔隙率、结晶度及β相含量均有影响.热拉伸温度为80℃时,微孔膜结晶度为58.86%,β相的相对含量最高达到42.50%,此时微孔膜的力学性能最佳;而当热拉伸温度为120℃时,PVDF微孔膜的成孔分布更加均匀,其孔隙率可达到最大值31.51%. 相似文献
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旋转切向流强化管式膜微滤机理研究 总被引:8,自引:2,他引:6
首次设计出了旋转切向流管式膜分离器及其实验系统,通过理论研究和实验测试,系统地研究了旋转直线切向流和旋转圆弧切向流聚丙烯管式膜微滤的流场特征,揭示了旋转切向流强化膜微滤的机理。 相似文献
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神经网络在膜技术中的应用 总被引:5,自引:2,他引:3
神经网络是一种旨在模仿人脑结构及其功能的软计算方法.它具有优良的容错性、自组织性和突出的非线性映射能力.最近几年,神经网络开始渗透到膜技术领域,为膜过程的研究和应用提供了一种全新的表达工具.目前,神经网络涉及到的膜过程包括MF、UF、NF以及RO等,在简要介绍了神经网络的结构与理论的基础上,分别评述了神经网络在这些膜过程中应用的研究现状,并展望了今后的研究方向, 相似文献
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研究了聚丙烯接枝聚丙烯酸微滤膜的pH响应性及其在牛血清蛋白溶液过滤中的抗污染性。聚丙烯酸(PAA)接枝链可提高膜亲水性,但会造成膜孔堵塞:在低接枝率(<17%)下,PAA大幅度提高膜亲水性,膜通量和pH响应性随接枝率的增加逐渐增大;接枝率过大(>17%)时,PAA对膜孔的堵塞作用占主导,膜通量和pH响应性逐渐下降。与未接枝膜相比,在碱性条件下接枝膜对牛血清蛋白(BSA)分子具有一定的抗污染性能,而酸性条件下则加剧BSA对膜的污染,但改性后接枝膜的通量大幅度增长,使这种膜在BSA类蛋白质的微滤领域仍有较好的应用前景。 相似文献
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Recent advances and avenues for further research and development in three specific fields of membrane science and technology
are reviewed. The potential of membrane processes for gas separation has been considerably improved by the development of
new materials combining high permeability and selectivity. While working correlations between polymer structure and permeation
characteristics have been evolved, there is need to further develop our basic understanding of this relationship. The second
field reviewed is that of improving the separation characteristics of porous membrane filtration (ultra-/microfiltration).
Recent promising approaches include the fabrication of membranes with uniform porosities, new module configurations and the
manipulation of feed chemistries. The third area highlighted is that of hybrid membrane processes. These are considered both
as integrated processes in which the membrane process operates in conjunction with another unit operation or as a coupled
transport process in which the basic functioning of the membrane is intimately coupled with another physical or chemical process
in single unit operation. The scope for basic research in these fields is indicated. 相似文献
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Keyu Ji Chengkun Liu Haijun He Xue Mao Liang Wei Fenglei Zhou Runjun Sun 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(33):2207330
Electrospinning technology has attracted extensive attention in recent decades and is widely used to prepare nanofiber membranes from hundreds of polymers. Polyvinyl formal acetal (PVFA), as a polymer with excellent properties such as high strength and heat resistance, is not reported on the electrospun water treatment membrane. In this paper, the preparation process of electrospun PVFA nanofiber membrane is optimized, and the effect of sodium chloride (NaCl) addition on the physical and mechanical properties and microfiltration performance of nanofiber membrane is also explored. And the hydrophobic PVFA nanofiber filter layer is then combined with a hydrophilic nonwoven support layer to construct a composite micro/nanofiber membrane with a pore-size gradient structure and a hydrophilic/hydrophobic asymmetric structure. Finally, unidirectional water transport and water treatment performance are further investigated. The results show that the tensile breaking strength of the composite membrane can reach up to 37.8 MPa, the retention rate for particles with the size of 0.1–0.3 µm is 99.7%, and the water flux is 513.4 L m−2 h−1 under the hydrostatic pressure. Moreover, it still has a retention of more than 98% after three repeated uses. Therefore, the electrospun PVFA composite membrane has a great potential in microfiltration. 相似文献
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《Membrane Technology》1992,1992(25):6-7
Claimed as a major advance in microfiltration technology, Ceramesh is an inorganic composite ceramic membrane that can be produced in a flat sheet suitable for use in process-scale crossflow filtration systems. The membrane combines a metal mesh and a ceramic to give strength, formability and both chemical and heat resistance The Ceramesh membrane technology has its origins in work carried out at Alcan Separations in Banbury and has been under development since 1988. Some of the original team had also worked on the development of the Anopore membrane, since commercialised by Anotec, and these close personal links have been maintained. Ceramesh Ltd was formed in 1990 by Alcan and a venture capital company with the aim of speeding the development of the membrane and ensuring its early introduction to the commercial filtration market. These objectives have now been achieved and by the middle of 1992 the Ceramesh membrane has been evaluated for a number of specific applications, been incorporated into a range of commercial filtration equipment, and formally launched into the chemical-process industries at the Eurochem exhibition held in Birmingham in June. 相似文献