添加剂草酸对酚酞基聚芳醚酮（PEK—C）微孔膜的影响

以新型耐高温工程塑料酚酞基聚芳醚酮(PEK-C)为膜材料,N,N-二甲基乙酰胺为溶剂,研究非溶剂添加剂草酸对铸膜液体系热力学性质和凝胶速率的影响,并考查添加剂草酸浓度对成膜结构与性能的影响,对草酸在PEK-C/DMAc铸膜液体系中的作用规律进行深入探讨.     

聚乙二醇对酚酞基聚芳醚酮多孔膜的影响

以新型耐高温工程塑料酚酞基聚芳醚酮(PEK-C)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂,研究了添加剂聚乙二醇(PEG)对铸膜液体系热力学性质和凝胶速率的影响,并考察了其浓度及分子量对成膜结构与性能的影响,对PEG系列添加剂在PEK-C/DMAc铸膜液体系中的作用规律进行了探讨。     

低温热致相分离法制备聚偏氟乙烯中空纤维多孔膜的研究

提出了一种低温热致相分离成膜方法(L- TIPS),通过干-湿法纺丝工艺制备了聚偏氟乙烯( PVDF)中空纤维多孔膜,考察了非溶剂致相分离法(NIPS)和热致相分离法(TIPS)两种成膜机理的竞争关系对膜形态结构和性能的影响.结果表明:低温热致相分离法在制备PVDF中空纤维膜的过程中同时发生了非溶剂致相分离机理和热致相分离机理,与单纯非溶剂致相分离机理成膜相比,膜断面未出现大的空穴,仅有少量指状孔,中部为球状结构,内外表面均有皮层,增强了膜的抗污染性能和强度;铸膜液浊点温度与凝固浴温差越大,壁厚越厚,热致相分离作用越明显,非溶剂致相分离作用相对减弱,膜的纯水通量和强度均有所提高,卵清蛋白截留率变化不大;低温热致相分离法比传统热致相分离法制膜温度低,能够添加常用的亲水性高分子添加剂(PVP、PEG、PVA).     

非溶剂添加剂对聚芳醚砜酮复合膜气体渗透性能的影响

以含二氮杂萘酮结构的聚芳醚砜酮(PPESK)为制膜材料,以硅橡胶为涂层材料,以N,N-二甲基乙酰胺(DMAc)为溶剂,采用干/湿相转化法,选用多种非溶剂添加剂(NSA),制备了中空纤维富氧膜.考察了非溶剂添加剂对纺丝液体系热力学性质及最终膜性能的影响;研究了不同非溶剂添加剂在延长蒸发距离时对膜性能的影响.为了考察膜的耐热性,将膜的测试温度控制在70℃.结果表明,非溶剂添加剂种类对纺丝液体系的热力学相平衡性质和膜性能的影响显著;随非溶剂添加剂含量的增加,膜的气体渗透率增大,氧/氮选择性降低;增大蒸发距离,非挥发性添加剂与挥发性添加剂对膜性能产生相反的影响.该膜耐热性能良好,在70℃下仍具有较好的选择性.     

N,N-二甲基乙酰胺/氯化锂体系下醋酸纤维素/聚醚砜共混膜的制备与表征

为提高纯聚醚砜(PES)膜的亲水性和抗污染能力,以N,N-二甲基乙酰胺/氯化锂(DMAc/LiCl)体系为溶剂,以聚乙烯吡咯烷酮(PVP K30)为添加剂,采用相转化法制备醋酸纤维素(CA)/聚醚砜(PES)共混膜.探讨和分析了成膜过程中的各种因素对膜纯水通量和BSA(牛血清蛋白)截留性能的影响.确定CA/PES共混膜的最佳铸膜条件为:聚醚砜质量分数18%,PVP K30的质量分数4%,醋酸纤维素质量分数3%,预蒸发时间为20s.对共混膜进行了SEM形貌结构、热稳定性、接触角测试、BSA抗污染性能和共混相容性分析表征.结果表明,DMAc/LiCl体系下制备的CA/PES共混膜亲水性和BSA抗污染性能高于纯PES膜,CA/PES共混体系为部分相容体系,CA/PES共混膜的高温热稳定性稍有下降.     

不同添加剂对聚偏氟乙烯膜结构和性能的影响

利用非溶剂相转化法(NIPS),以N,N-二甲基乙酰胺(DMAc)为溶剂,聚乙烯吡咯烷酮(PVPK30)和一水合氯化锂(LiCl·H2O)为混合添加剂,改变PVPK30-LiCl·H2O配比得到不同性能和结构的聚偏氟乙烯(PVDF)膜。考察了不同种类添加剂(PVP、LiCl·H2O、H2O和PEG200)及不同配比的PVPK30-LiCl·H2O添加剂对PVDF成膜分相延时时间、分相速率的影响。实验结果表明,采用PVPK30为添加剂,铸膜液呈瞬时分相行为,膜通量很大;增大混合添加剂中PVPK30/LiCl·H2O的比例,会增加液液分相速率,使膜结构中的大孔贯通整个膜结构。     

杂萘联苯聚醚砜酮类材料成膜动力学研究(Ⅰ)添加剂对PPESK凝胶动力学的影响

以杂萘联苯聚醚砜酮(PPESK)/NMP为铸膜液体系,进行成膜过程凝胶动力学研究.发现凝胶动力学曲线(X2~t)不是由单一直线组成的,而是由三段对应着不同膜结构的直线组成.考察了不同添加剂对PPESK-NMP体系凝胶速度的影响.结果表明,亲水性强的添加剂,可提高铸膜液体系的亲水性,从而加快溶剂、非溶剂的传质速率,凝胶速度加快,膜的水通量增加.使铸膜液黏度增加的添加剂,使非溶剂扩散系数降低,凝胶速度减慢,膜的水通量减少.丙二酸添加剂增大了铸膜液的亲水性,使铸膜液的凝胶速度增大.吐温添加剂既增加了铸膜液的亲水性又增加了铸膜液的黏度,凝胶速度也先变小后变大.PEG添加剂虽然增大了铸膜液体系的亲水性,但同时也提高了铸膜液的黏度,凝胶速度的变化不大.     

NIPS法疏水PVDF膜的结构与性能调控研究进展

非溶剂致相分离法(NIPS)是制备多孔有机膜一种高效工艺手段,其过程中涉及的热力学与动力学因素对于疏水多孔膜的成膜结构与性质起着至关重要的决定性作用.为此,本文以常用疏水膜制备原材料聚偏氟乙烯(PVDF)为研究对象,系统阐述采用传统浸没沉淀相转化法和新兴喷雾辅助相转化法两种NIPS制膜工艺路线对PVDF疏水膜微纳结构的影响及其内在成膜机理,旨在通过明晰制膜过程中影响因素对成膜疏水性、孔结构参数的作用规律,为疏水膜的可控制备提供理论指导与技术支持.     

不对称聚乙烯醇缩丁醛超滤膜的形成

采用浸没沉淀相转化法在二甲基乙酰胺(DMAC)、N-甲基吡咯烷酮(NMP)、二甲基甲酰胺(DMF)及二甲亚砜(DMSO)等4种溶剂下制备了聚乙烯醇缩丁醛(PVB)超滤膜,铸膜液组成为PVB-溶剂二元体系,水为非溶剂.利用扫描电子显微镜(SEM)观察了PVB膜的表面形貌与断面结构,并对其渗透及分离性能进行了测试,同时着重讨论了PVB膜表面结构的形成机理.结果表明,溶剂种类不仅决定了PVB-溶剂二元体系的热力学稳定性,同时也影响了其成膜过程的动力学效应;PVB膜断面结构受溶剂-非溶剂相互扩散速度的控制,而膜表面形貌则是铸膜液平衡热力学与成膜动力学结合的结果;不同溶剂的PVB超滤膜纯水通量大小的顺序依次为DMSO＞DMAC＞DMF＞NMP,其截留分子量则分别在40 000～50 000道尔顿之间.     

阳离子季铵型表面活性剂对PVDF/PHEMA共混微滤膜的成膜性能研究

采用凝胶相转化法,以聚偏二氟乙烯(PVDF)/聚甲基丙烯酸-2-羟基乙酯(PHE-MA)共混合金为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂,阳离子季铵型表面活性剂(TM)为添加剂制备微滤膜.考察了添加剂浓度对铸膜液相容性、铸膜液黏度、铸膜液凝胶速度、膜结构和性能的影响.对PVDF/PHEMA/DMAc铸膜液体系中TM添加剂的作用规律进行了研究.实验发现:TM添加质量分数小于5.0%时,铸膜液中组分的相容性得到很大改善,制备出的微滤膜表面孔径均一、孔密度高.随着TM添加浓度的增大,铸膜液黏度先减小后增大,凝胶速度逐渐增大,膜的纯水通量先增大后减小,截留率则始终上升.     

有机溶剂对PVDF铸膜液热力学性质及其膜结构性能的影响

考察了10种小分子有机溶剂添加剂对PVDF／DMAc制膜体系热力学与膜结构的影响。结果发现，小分子有机溶剂添加剂使铸膜液体系的凝胶值降低，即热力学稳定性降低。当铸膜液中添加了EtOH、i-PrOH、PgOH、PtOH时，膜中指状大孔结构充分发展，并且膜的孔隙率高、气通量大。而DtOH、BtOH、OtOH、PrA、AC和MeAt添加剂则使得大孔的结构减少，并且孔隙率低、气通量小。最后从热力学性质与扩散两个角度进行了成膜机理的探讨，当使用EtOH、i-PrOH、PgOH、PtOH添加剂时，铸膜液中由于PVDF超分子聚集态结构的生成使得体系的耐非溶剂性能大大降低，也正是铸膜液中存在的PVDF超分子聚集态结构使得扩散速度加快，分相速度提高，于是大孔结构得到发展。     

聚偏氟乙烯／磺化聚砜共混相容性及超滤膜研究

聚偏氟乙烯与磺化聚砜属部分相容体系,采用溶胶－凝胶相转化法制备了以聚酰无纺布为支撑体的聚偏氟乙烯／磺化聚砜共混超滤膜,通过对膜水通量,截留率与孔隙率的测定及其扫描电镜微观分析得到,聚偏氟乙烯／磺化聚砜共混膜较聚偏氟乙烯膜具有更好的分离透过特性。     

天然纤维粉体对PVDF/DMAc体系热力学及膜结构的影响

考察天然纤维粉体/聚偏氟乙烯(PVDF)/N,N-二甲基甲酰胺(DMAc)铸膜液热力学性质,采用浸没沉淀相转化法制备了天然纤维粉体/PVDF共混膜,表征了共混膜的结构和性质。结果表明,按照棉花粉体、羊毛粉体、无粉体的顺序,制膜体系越来越容易发生液固分相;并且棉花粉体/PVDF共混膜、羊毛粉体/PVDF共混膜、PVDF膜的孔隙率和水通量依次降低,结晶度依次增加,但膜形态一致,均为致密皮层和多孔亚层。共混膜性质的差异主要是由于纤维粉体亲水性的不同,添加亲水性较好的羊毛粉体的铸膜液成膜速度慢,而添加亲水性较低的棉花粉体的铸膜液成膜速度较快。     

PVDF/SMA共混膜的制备与性能

通过马来酸酐和苯乙烯合成了苯乙烯/马来酸交替共聚物(SMA),并按不同质量比与聚偏氟乙烯(PVDF)共混,通过溶液相转化成膜法制备了PVDF/SMA共混膜。采用红外光谱、扫描电镜、膜通量测试等对不同铸膜液所形成膜的结构和性能进行了研究。结果表明,随着铸膜液中交替共聚物含量增大,所成膜及膜表面交替共聚物含量增大,膜孔尺寸增大,膜孔隙率升高,纯水通量增大,蛋白质截流能力下降,膜表面亲水性和耐蛋白污染能力增强。     

表面喷涂壳聚糖溶液对聚偏氟乙烯多孔膜的结构和性能的影响

在聚偏氟乙烯(PVDF)溶液膜表面喷涂壳聚糖(CS)醋酸溶液,用浸没相转变法制备PVDF多孔膜,研究CS溶液对多孔膜的结构和性能的影响并探讨了成膜机理。结果表明,随着溶液膜表面CS溶液体积的增加PVDF膜的孔隙率提高,膜表面的亲水性大幅度提高,β晶含量降低而α晶的含量提高;喷涂CS溶液前PVDF膜的上表面结构致密,喷涂CS溶液后PVDF膜上表面呈现多孔结构,其断面结构均为指状大孔结构;喷涂CS溶液的体积为2 mL、4 mL和6 mL的PVDF膜,其水通量先增加后降低,分别为683.33 L/m²·h、1121.57 L/m²·h、1171.36 L/m²·h和1029.02 L/m²·h。用不同方法制备的PVDF膜,其结构和性能不同,因为膜上表面的成膜机理不同。     

Surface characteristics and blood compatibility of PVDF/PMMA membranes

Poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) membranes have important applications as biomaterials. In this study, PVDF/PMMA with varying ratios is blown into membranes, the surface property and blood compatibility of which are thoroughly investigated. Membrane surface characteristics including composition and topography exert considerable influence on the blood compatibility. Introduction of PMMA disturbs PVDF crystallization, however, favors the β phase crystal formation. PVDF content, crystallization ability, and surface enrichment have decisive effects on the membrane surface composition. Meanwhile, with increased PMMA fraction, the membrane surface roughness is also increased, and subsequently results in decreased hemocompatibility. While the membranes with PMMA content lower than 30 wt% show good blood compatibility, those with higher PMMA fraction exhibit obvious platelet adhesion to the surface. Thermal annealing promotes the formation of β phase PVDF and generates much smoother surface, thus endowing the membranes with greatly enhanced blood compatibility. These results show the prospect for optimization of processability, surface property, and blood compatibility of PVDF/PMMA membranes through facile modulation of PMMA content and fabrication process.     

添加剂PEG对PVDF/SiO_2杂化膜性能的影响

在PVDF/SiO2体系中添加了PEG,利用浸没沉淀相转化法制备了PVDF/SiO2杂化膜,并对膜性能进行测试,采用SEM观察膜表面与断面的微孔结构.结果表明:铸膜液中加入PEG,促进了SiO2在PVDF体系中的分散,增加了界面微孔数量,该膜试样在保持较高截留率的情形下,水通量得到了一定程度的提高.SEM断面照片显示,在PVDF/SiO2体系中加入PEG,制备的PVDF/SiO2杂化膜试样中大孔的数量增多,而且孔壁上细小微孔数量也增多.     

Crystallization behavior of PVDF/PMMA blends prepared by in situ polymerization from DMF and ethanol

The crystallization behavior of poly(vinylidene fluoride)/poly(methyl methacrylate) (PVDF/PMMA) blends was investigated at different PMMA content and from two solvents N,N-dimethylformamide (DMF) and ethanol. The PVDF/PMMA blends were obtained by in situ polymerization of methyl methacrylate (MMA) in the solution of PVDF in DMF. The crystalline phases of PVDF were dependent on crystalline solvents and independent on PMMA content. For the in situ PVDF/PMMA blends, β phase of PVDF was predominant when they were crystallized from their good solvent DMF, while PVDF exhibited well-defined α and β phases from non-solvent ethanol. However, the relative fraction of β phase of PVDF in blends crystallized from ethanol varied with PMMA content. The crystallization morphology was related to crystallization solvent and PMMA content. The in situ blends crystallized from DMF and ethanol presented spherulites morphology and numerous minute particle structures, respectively. The addition of PMMA could reduce the spherulite size of PVDF. Thermal properties of in situ blends were also dominated by crystallization solvent and PMMA content. For the blends crystallized from DMF, their peak melting temperatures and lamellar thickness calculated by WAXD showed a first increasing and then decreasing tendency. At the same PMMA content, the blends crystallized from ethanol had a higher degree of crystallinity (X _c) of PVDF compared with those from DMF. In addition, the X _c calculated by DSC increased noticeably at PMMA content of 1.0 wt% and afterward it decreased with PMMA content, regardless of the kind of crystallization solvent. Besides, the hydrophilicity of the PVDF/PMMA blends was improved with PMMA content based on contact angle measurements.     

氧化石墨烯-氨基酰化酶/聚偏氟乙烯复合膜的制备及特性

通过静电吸附法成功制备了氧化石墨烯-氨基酰化酶（GO-acylase）颗粒。将GO和GO-acylase颗粒分别添加到聚偏氟乙烯（PVDF）铸膜液中,通过相转化法制备了GO/PVDF和GO-acylase/PVDF复合膜。结果显示,GO-acylase/PVDF复合膜的粗糙度最低（R_a=8.21 nm）,表面最平滑。GO/PVDF和GO-acylase/PVDF复合膜的接触角较小（73.72°和71.31°）,说明复合膜的亲水性优于纯PVDF膜。由于GO的添加会增强溶质和非溶质之间的转化过程,从而导致GO/PVDF复合膜的纯水通量最大（69.0 L/（m2 h））。经过测定,GO-acylase/PVDF复合膜的生物活性在4℃下可以持续4周左右。研究结果表明,GO-acylase/PVDF复合膜的成功制备为抗生物污染膜的研发提供了新思路。      

Zwitterionic sulfobetaine-grafted poly(vinylidene fluoride) membrane with highly effective blood compatibility via atmospheric plasma-induced surface copolymerization

Development of nonfouling membranes to prevent nonspecific protein adsorption and platelet adhesion is critical for many biomedical applications. It is always a challenge to control the surface graft copolymerization of a highly polar monomer from the highly hydrophobic surface of a fluoropolymer membrane. In this work, the blood compatibility of poly(vinylidene fluoride) (PVDF) membranes with surface-grafted electrically neutral zwitterionic poly(sulfobetaine methacrylate) (PSBMA), from atmospheric plasma-induced surface copolymerization, was studied. The effect of surface composition and graft morphology, electrical neutrality, hydrophilicity and hydration capability on blood compatibility of the membranes were determined. Blood compatibility of the zwitterionic PVDF membranes was systematically evaluated by plasma protein adsorption, platelet adhesion, plasma-clotting time, and blood cell hemolysis. It was found that the nonfouling nature and hydration capability of grafted PSBMA polymers can be effectively controlled by regulating the grafting coverage and charge balance of the PSBMA layer on the PVDF membrane surface. Even a slight charge bias in the grafted zwitterionic PSBMA layer can induce electrostatic interactions between proteins and the membrane surfaces, leading to surface protein adsorption, platelet activation, plasma clotting and blood cell hemolysis. Thus, the optimized PSBMA surface graft layer in overall charge neutrality has a high hydration capability and the best antifouling, anticoagulant, and antihemolytic activities when comes into contact with human blood.