稀释剂对热致相分离法制备聚偏氟乙烯膜结构的影响

以聚偏氟乙烯(PVDF)和一种在常温下为固态的水溶性潜溶剂己内酰胺(CPL)为膜材料和稀释剂,基于热致相分离原理,制备了PVDF微孔膜,通过差示扫描量热仪对不同条件下二元共混物的结晶性能进行了分析,利用扫描电镜研究了稀释剂含量对膜微观结构的影响。结果表明,PVDF质量分数小于25%,PVDF/CPL高温溶液体系在降温过程中发生液-液相分离,主要形成了双连续网络孔结构。研究了PVDF浓度对膜水通量、BSA截留率、膜强度等的影响,该研究为用单一水溶性稀释剂制备PVDF微孔膜定了基础。     

热致相分离法制备聚偏氟乙烯微孔膜的研究

热致相分离法是一种制备聚合物微孔材料的有效方法。介绍了聚合物初始浓度、稀释剂、降温速率、成核剂、萃取剂等因素对热致相分离法制备聚偏氟乙烯（PVDF）微孔材料的影响,并对热致相分离法制备聚偏氟乙烯（PVDF）微孔膜的最新研究进展进行了介绍。     

聚偏氟乙烯中空纤维膜的研制

本文选用聚偏氟乙烯作为膜材料,二甲基甲酰胺为溶剂,聚乙二醇为添加剂,采用湿法纺丝成膜,对影响膜性能的诸因素进行了讨论,用所制的中空纤维膜组件对TNT废水进行了膜萃取实验。用回归正交实验设计确定的最佳配方为聚偏氟乙烯浓度22.14%,聚乙二醇浓度6.26%,二甲基甲酰胺71.60%,纺丝温度54.84℃。该最优组合膜的萃取速率为1.898mg/m     

添加剂对聚偏氟乙烯中空纤维超滤膜结构及性能的影响

在聚偏氟乙烯(PVDF)铸膜液中添加聚乙烯砒咯烷酮(PVP)、LiCl和苯乙烯-马来酸酐共聚物(SMA),采用相转化法制备了PVDF中空纤维共混超滤膜,并通过扫描电镜表征、膜通量和截留率测试等手段,研究了聚合物含量和不同添加剂对PVDF中空纤维膜的结构和性能的影响.结果显示,随着聚合物PVDF含量的增加,膜通量减小、截留率增加、拉伸强度增加;添加剂SMA对膜性能影响较大,PVP和LiC1含量对膜的结构及性能影响较小,随其含量的增加,膜截留率增加.     

聚偏氟乙烯微孔膜制备方法研究进展

介绍了浸没沉淀法、热致相分离法以及蒸发助热致相分离法制备聚偏氟乙烯(PVDF)微孔膜的研究进展.重点介绍了溶剂、凝固浴组成、凝固浴温度、添加剂和蒸发时间等因素对浸没沉淀法制备PVDF膜的影响,并对制备PVDF膜的发展提出建议和展望.同时简单介绍了PVDF微孔膜的亲水性改性.     

凝固浴温度对PVDF/PES-C共混膜结构及性能的影响

以邻苯二甲酸二丁酯(DBP)和N,N-二甲基乙酰胺(DMAc)为混合稀释剂,采用热致相分离法(TIPS)制备了聚偏氟乙烯(PVDF)/酚酞型聚醚砜(PES-C)共混膜,考察了不同凝固浴温度对膜结构和性能的影响。采用扫描电镜观察了膜的结构,测试了膜的纯水通量。运用DSC和XRD方法检测了膜的结晶性能。将制备的膜在膜生物反应器(MBR)中运行测试了膜的污水通量和出水指标。随凝固浴温度的升高,共混膜的最高熔融温度上升,膜中α晶型的含量增加。在凝固浴温度为25℃时,膜形成了较为致密的皮层结构和较为疏松的支撑层结构,此时共混膜的纯水通量和污水通量达到最大值,且MBR出水COD和NH4+-N含量达到排放要求。     

混合稀释剂对热致相分离法制备聚偏氟乙烯膜性质及结构的影响

采用邻苯二甲酸二丁酯(DBP)为稀释剂,通过加入部分N,N-二甲基乙酰胺(DMAc)或邻苯二甲酸二辛酯(DOP),分别在150℃和220℃下,采用热致相分离法制备了聚偏氟乙烯(PVDF)平板膜,研究了在较低温度下或高温下制得膜的性能和结构。结果表明,加入质量分数10%的DMAc在150℃下制膜,比采用纯的DBP为稀释剂时膜的通量提高了28%,过多DMAc的加入反而会使膜的通量降低;加入质量分数10%的DOP在220℃下制膜,膜的通量则下降了62%。同时采用扫描电镜观察了膜的截面结构,解释了采用不同混合稀释剂时膜形成不同结构的原因。     

超亲水聚偏氟乙烯中空纤维膜的制备及性能

聚偏氟乙烯(PVDF)中空纤维膜是一种新型高分子材料分离膜,具有优异的化学稳定性、高通量、高分离率和高填充性密度,在水处理行业越来越普遍应用.运用原位超声波辅助接枝技术在PVDF膜的表面上接枝含有环氧基团的GMA,将其作为空纤维膜的中间层,再通过氨基将环氧基团诱导出来,促使其产生开环反应,然后在PVDF膜的表面接枝苏氨...     

中科院制成抗菌双层聚偏氟乙烯中空纤维膜

<正>近日,中科院宁波材料技术与工程研究所高分子事业部功能膜团队通过双层共挤出技术制备出外层富集抗菌银离子的双层聚偏氟乙烯(PVDF)中空纤维膜。此前,该团队研究人员通过非溶剂诱导辅助热致相分离法已制备出双连续结构的PVDF膜,以及具有良好抗菌性能的中空纤维膜。在此基础上,为了减少     

PVDF/PES-C共混膜的结构与性能

以邻苯二甲酸二丁酯(DBP)和N,N-二甲基乙酰胺(DMAc)为混合稀释剂,采用热致相分离法(TIPS)制备了聚偏氟乙烯(PVDF)和酚酞型聚醚砜(PES-C)共混膜,采用扫描电镜观察了膜的截面结构,测试了膜的纯水通量。通过膜生物反应器处理生活污水,检验了膜的污水处理性能。与PVDF膜相比,共混膜具有一个较薄的致密的皮层和较为疏松的支撑层,共混膜的纯水通量约为纯聚偏氟乙烯膜的两倍。同时共混膜的污水通量较高,COD和NH4+-N的去除率与PVDF膜相比约增加10%,共混膜的通量衰减系数较小,具有更好的抗污染性能。     

膜生物反应器中PVDF中空纤维膜亲水性变化特征

为研究膜生物反应器(MBR)中PVDF中空纤维膜的亲水性变化特征,提出以接触角变化速率的绝对值(λ)表征亲水性的方法 ,按轴向长度将膜纤维划分为4个位置,考察过滤和清洗对膜亲水性的影响。结果表明:在MBR运行过程中,膜污染的加剧与膜的亲水性变化有关,膜纤维通量越高的位置,膜的亲水性越差。采用物理反洗和短时间的化学浸泡清洗,膜的亲水性能得到一定恢复,但效果有限。延长化学浸泡清洗时间发现,浸泡3 h膜纤维的亲水性最好。     

Preparation of PET threads reinforced PVDF hollow fiber membrane

PET threads were incorporated in the support layer of hollow fiber membrane in axial direction as a special reinforcement material for the purpose of improving the mechanical properties of PVDF hollow fiber membranes. It was found that the reinforcement threads had a limited effect on the separation-related properties of the membrane, such as porosity and pore size, but the tensile strength of the reinforced membrane was improved several folds. Also, the criterion of choosing reinforced fiber materials was suggested.     

介孔Al_2O_3/PVDF复合中空纤维膜的制备及其性能

为了提高PVDF中空纤维膜在处理含油废水过程中的亲水性能、抗压实性能和抗污染性能,实验以介孔Al2O3为无机添加粒子,采用溶液纺丝法制备出介孔Al2O3/PVDF复合中空纤维膜。通过扫描电子显微镜和傅里叶红外光谱观察介孔Al2O3/PVDF复合中空纤维膜的形貌和成分,结果证明介孔Al2O3成功地添加到PVDF中空纤维膜中。通过接触角,纯水和含油废水通量的测试,结果表明介孔Al2O3的添加改善了PVDF膜的亲水性能、抗压实性能和抗污染性能。     

Surface modification of PVDF hollow fiber membrane to enhance hydrophobicity using organosilanes

This work investigates the membrane modification to enhance hydrophobicity aiming for applications as membrane contactors. The PVDF membranes were activated by NaOH and by plasma activation followed by grafting using three organosilanes. For the NaOH, the contact angle of original membranes (68°) was decreased from 44° to 31° with increasing NaOH concentration from 2.5M to 7.5M at 60°C for 3 h. The contact angle of NaOH treated membranes was increased to 100° after modification with 0.01M FAS‐C8 for 24 h. A needle‐like structure was observed on the membrane surface while there was no significant change in pore size and pore size distribution. Moreover, FTIR and XPS data showed Si peak and composition. The mechanical strength was improved. The surface modified membranes under helium plasma activation followed by grafting with 0.01M FAS‐C8 for 24 h showed higher contact angle, mechanical strength and surface roughness than that obtained by NaOH activation method while other physical properties did not change. The long‐term performance test for 15 days of operation was conducted. The modified membranes exhibited good stability and durability for CO₂ absorption. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and anti-fouling property of carboxybetaine-based zwitterionic PVDF membrane

This work describes the synthesis and anti-fouling properties of poly(vinylidene fluoride) membrane, grafted with carboxybetaine-based zwitterions. An amphiphilic copolymer, poly(vinylidene fluoride)-graft- poly(N,N-dimethylamino-2-ethylmethacrylate) (PVDF-g-PDMAEMA), was synthesized by radical graft copolymerization, followed by casting the copolymer into a flat membrane, by an immersed phase inversion method. PVDF-g-PDMAEMA membrane was reacted with sodium chloroacetate (SCA) to yield a carboxybetaine-based zwitterionic surface. The membrane showed significantly enhanced hydrophilicity, due to the hydration ability of carboxybetaine-based zwitterions, which inhibited protein adsorption. Compared to pristine PVDF-g-PDMAEMA membrane, carboxybetaine-based zwitterionic membrane exhibited a higher flux recovery in the cyclic filtration.