PVDF纤维湿纺研究

本文论述了PVDF(偏二氟乙烯)等可溶性含氟树脂以DMSO(或DMF)为溶剂的湿法纺丝工艺,着重对影响氟物性的有关因素进行了讨论与阐述.     

PVDF/TiO2杂化纤维膜的制备及其性能分析

采用静电纺丝的方法制备聚偏氟乙烯（PVDF）/二氧化钛（TiO2）杂化纤维膜,并利用扫描电子显微镜、X射线衍射仪和可见分光光度计等仪器对杂化纤维膜的微观形貌、晶体结构、力学性能以及光催化性能进行研究与分析。结果表明,随着TiO2添加量的增加,PVDF/TiO2杂化纤维膜表面暴露的TiO2增加;杂化纤维膜的拉伸强度呈现先增后减的趋势;且杂化纤维膜的光催化降解能力逐渐增强;同时PVDF/TiO2杂化纤维膜具有良好的重复利用性。     

Ag/TiO2/PVDF复合纤维膜的制备及光催化性能研究

采用静电纺丝结合溶胶法制备了一系列不同Ag/TiO₂含量的Ag/TiO₂/PVDF复合纤维膜,并利用傅里叶红外光谱(FT-IR)、扫描电镜(SEM)、干湿重法、过滤测试法、微电脑抗张强度测定仪等对复合纤维膜的微观形貌、力学性能等进行表征和研究,结果表明添加适当的Ag/TiO₂时,所制备的Ag/TiO₂/PVDF复合纤维膜纤维表面比较平滑,具有较大的平均孔径和较高的孔隙率,且抗拉强度和伸长率均有所提高,但如过量添加Ag/TiO₂,则会导致膜性能受到影响。对Ag/TiO₂/PVDF复合纤维膜光催化降解溶液中亚甲基蓝(MB)的性能进行研究,结果表明,相较于PVDF原膜,Ag/TiO₂/PVDF复合纤维膜对于MB的光催化降解性能有显著提升,且其光催化降解过程符合准一级动力学模型。循环利用性能测试结果表明,Ag/TiO₂/PVDF复合纤维膜重复利用性较好,具有实际应用前景。     

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。     

PVDF/PMMA复合材料膜的性能及应用

介绍了聚偏氟乙烯(PVDF)/聚甲基丙烯酸甲酯(PMMA)复合材料膜以及引入石墨烯之后复合材料膜的性能和应用研究。相关研究表明:PVDF/PMMA复合材料膜在新能源、水处理以及医疗领域有重要的应用价值,在新型膜材料领域具有极大的发展潜力。     

PVDF/PU相容性及其复合管状膜的制备

采用溶解度参数和混合焓计算预测聚偏氟乙烯（PVDF）／聚氨酯（PU）的相容性,用黏度法测试了PVDF／PU共混溶液的混容性．用浊度法测试了PVDF／PU共混制膜体系的热力学性质,并制备了PVDF／PU复合管状膜。结果显示,PVDF／PU属于部分相容体系,当w（PU）为10％～90％时,制膜体系的凝胶值由5．30增至9．93,体系更加倾向于发生快速的液液分相,导致复合膜孔隙率增加,当Ⅵ妒叻为0-40％时,水通量从2456．2L（m^2·h）增至5830．9L/（m^2·h）。     

膜蒸馏用PDMS/PVDF/PTFE三元共混微孔膜制备

采用浸没沉淀相转化法制备了聚二甲基硅氧烷/聚偏氟乙烯/聚四氟乙烯（PDMS/PVDF/PTFE）三元共混微孔膜,并用于20 g/L NaCl水溶液的膜蒸馏脱盐实验。通过扫描电子显微镜观察以及接触角、膜孔隙率和膜平均孔径分析,研究了PTFE含量对膜结构与性能的影响。结果表明,随着PTFE含量的增加,共混微孔膜断面的指状孔逐渐被海绵状取代,平均孔半径由0.234 μm增加到0.354 μm,膜孔隙率由53.4 %增加到81.3 %;膜下表面与水接触角从118.52 °增加到131.11 °;膜蒸馏过程中通量逐渐增加,截留率先稳定后降低,PTFE含量为40 %（质量分数,下同） 时达最大,为99.99 %,此时膜蒸馏通量达16.60 kg/(m2·h)。     

强疏水性PDMS/PVDF微孔膜的制备及其性能研究

利用非溶剂相转化法（NIPS）,通过在聚偏氟乙烯(PVDF)铸膜液中加入聚二甲基硅氧烷(PDMS),制备了PDMS/PVDF共混疏水微孔膜,并研究了凝胶浴组成（水/乙醇）对铸膜液凝胶动力学、膜形貌、疏水性及力学性能的影响。结果表明,随着凝胶浴中乙醇百分含量由零增加至100 %时,PDMS/PVDF共混膜的断面上指状孔基本消失,海绵状孔结构贯穿断面;当凝胶浴中乙醇含量为100 %时,PDMS与PVDF发生分相;膜表面疏水性能增加,水接触角达到139.68 °;弹性模量、拉伸强度、断裂伸长率分别由（48.06±4.20）、（2.82±0.15） MPa、（92.90±2.53） %下降至（15.70±2.83）、（0.72±0.13） MPa、（15.47±1.63） %。     

m-ZrO_2/PVDF共混膜的制备及性能研究

针对PVDF膜在应用中亲水性差、易污染的缺陷,以小粒径的单斜相纳米Zr O2作添加剂,制备了1种新型m-Zr O2/PVDF共混膜,用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)对该膜进行了物相及化学基团分析,用发射场扫描电镜(FSEM)观察表征了该膜表面与断面结构,并研究了m-Zr O2纳米颗粒质量分数在0~1%时,该膜的亲水接触角、纯水通量、截留率及通量恢复率等关键膜性能指标的变化情况。结果表明,m-Zr O2纳米颗粒的适宜加入量为质量分数0.75%,这可使PVDF膜的纯水通量、BSA过滤通量及纯水通量恢复率均提高约30%。     

PVDF中空纤维膜的制备及冷拉伸处理对其性能的影响

用干-湿纺丝法制备聚偏氟乙烯(PVDF)中空纤维膜,用万能拉力仪进行冷拉伸处理,分别拉伸0.9、1.2、1.5、1.8倍.研究拉伸前后的中空纤维膜的纯水通量、牛血清白蛋白(BSA)通量衰减、孔隙率等基本性能,用电镜观察膜的表面形貌,用万能拉力仪测试膜的力学性能,用红外光谱仪分析膜内的晶体结构.结果显示,拉伸会影响中空纤维膜的基本性能及表面形貌.拉伸1.8倍为最佳拉伸倍数,此法可简易制得性能良好的高通量微孔膜.     

静电纺丝PBT/PVA复合膜的制备及性能研究

以三氟乙酸和二氯甲烷为混合溶剂,采用静电纺丝法制备聚对苯二甲酸丁二酯(PBT)/聚乙烯醇(PVA)复合膜。用旋转粘度计和电导率仪测定溶液的黏度和电导率,用扫描电子显微镜、拉伸和水接触角测试PBT/PVA不同比例对纤维膜的形貌、力学和亲水性能的影响。结果表明,随着PVA比例的增加,混合溶液的黏度逐渐增大,而电导率先增大后减小;当PBT/PVA的比例为90/10时,纳米纤维的平均直径最小,为323 nm,而其纳米纤维膜的力学性能与纯PBT纤维膜相比显著提高,拉伸强度、弹性模量和断裂伸长率分别增加了213%,260%和57%;PVA的加入改善PBT纤维的亲水性,制备出力学性能优异且亲水的PBT/PVA纤维膜。     

Crystal polymorphism in electrospun composite nanofibers of poly(vinylidene fluoride) with nanoclay

We investigated for the first time the morphology and crystal polymorphism of electrospun composite nanofibers of poly(vinylidene fluoride) (PVDF) with two nanoclays: Lucentite™ STN and SWN. Both nanoclays are based on the hectorite structure, but STN has organic modifier in between the layers of hectorite while SWN does not. PVDF/nanoclay was dissolved in N,N-dimethylformamide/acetone and electrospun into composite nanofiber mats with fiber diameters ranging from 50-800 nm. Scanning electron microscopy shows that addition of STN and SWN can greatly decrease the number of beads and make the diameter of the nanofibers more uniform due to the increase of electrospinning solution conductivity brought by the nanoclay. Infrared spectroscopy and X-ray diffraction confirm that both STN and SWN can induce more extended PVDF chain conformers, found in beta and gamma phase, while reducing the alpha phase conformers in electrospun PVDF/Nanoclay composite nanofibers. With the attached organic modifier, even a small amount of STN can totally eliminate the non-polar alpha crystal conformers while SWN cannot. The ionic organic modifier makes STN much more effective than SWN in causing crystallization of the polar beta and gamma phases of PVDF. An ion-dipole interaction mechanism, suggested by Ramasundaram, et al. is utilized to explain the crystal polymorphism behavior in electrospun PVDF/nanoclay composite nanofibers.     

EB‐crosslinked Polymer Electrolyte Membranes Based on Highly Sulfonated Poly(ether ether ketone) and Poly(vinylidene fluoride)/Triallyl Isocyanurate

In this study, crosslinked polymer electrolyte membranes for polymer electrolyte membrane fuel cell (PEMFC) applications are prepared using electron beam irradiation with a mixture of sulfonated poly(ether ether ketone) (SPEEK), poly(vinylidene fluoride) (PVDF), and triallyl isocyanurate (TAIC) at a dose of 300 kGy. The gel‐fraction of the irradiated SPEEK/PVDF/TAIC (95/4.5/0.5) membrane is 87% while the unirradiated membrane completely dissolves in DMAc solvent. In addition, the water uptake of the irradiated membrane is 221% at 70 °C while that of the unirradiated membrane completely dissolves in water at above 70 °C. The ion exchange capacity and proton conductivity of the crosslinked membrane are 1.57 meq g⁻¹, and 4.0 × 10⁻² S cm⁻¹ (at 80 °C and RH 90%), respectively. Furthermore, a morphology study of the membranes is conducted using differential scanning calorimetry and X‐ray diffractometry. The cell performance study with the crosslinked membrane demonstrates that the maximum power density is 518 mW cm⁻² at 1036 mA cm⁻² and the maximum current density at applied voltage of 0.4 V is 1190 mA cm⁻².     

辐射对PVDF/氟橡胶/CB复合物PTC特性的影响

研究了电子束辐照对聚偏氟乙烯／氟橡胶／炉法炭黑导电复合材料正温度系数复演性及电阻稳定性的影响规律。结果表明,随辐射剂量提高,凝胶含量上升,ＰＴＣ复演性提高。由该体系制得的自限温伴热带的长期使用工作温度及功率稳定性提高,通断电循环试验的功率及电阻变化较小,可用于制备１３５℃高温级处限温伴热带。     

丙烯酸酯三元共聚物酸掺杂改性聚苯胺的研究

选择丙烯酸 (AA)、丙烯酸丁酯 (BA)和甲基丙烯酸甲酯 (MMA)三元共聚物对聚苯胺 (PAn)进行改性 ,研究了BA的用量和引发剂浓度对PAn导电率的影响 ,对样品进行DSC、FTIR和SEM测试。结果表明 ,丙烯酸酯三元共聚物酸对PAn有良好的掺杂改性作用 ,当共聚单体 (AA -BA -MMA)组成为 10∶45∶45 (质量比 ) ,引发剂浓度为0 0 5 48mol·L-1时 ,可制得电导率达 1 42 1S·cm-1的导电PAn。     

Synthesis and Characterization of Lewis Acid Doped Polyaniline and Its Application as Catalysts for Acetalization of Carbonyl Compounds

Lewis acid doped polyanilines are prepared by doping of polyaniline base with Lewis acids. Polyaniline base and Lewis acid doped polyanilines are characterized by physical and spectral methods. They are used as catalysts for the first time for acetalization of carbonyl compounds. The catalyzed acetalization of benzaldehyde with propane-1,2-diol is conducted in excellent yields with simple and more environmentally benign procedure. The use of these doped lewis acid catalysts is feasible because of being ecofriendly, their easy preparation, easy recovery, reusability, and good activity.     

Properties of Sulfonated Poly(Arylene Ether Sulfone)/Functionalized Carbon Nanotube Composite Membrane for High Temperature PEMFCs

Composite membranes are prepared using sulfonated poly (arylene ether sulfone) (SPAES) copolymers and the incorporation of functionalized multiwall carbon nanotubes (CNTs) for high temperature (120 °C) proton exchange membrane fuel cells (PEMFCs). The CNT is functionalized with sulfonated groups that are expected to support the improvement of water absorption and mechanical properties. The SPAES copolymers are synthesized with sulfonation degree (DS) = 0.5 and the sulfonated CNT (s‐CNT) is dispersed into the SPAES copolymers in varying ratios to fabricate the composite membranes. In this study, the proton conductivity, water uptake, and single cell test of the composite membrane are investigated for verifying the effects of the enhancement at high temperature and low humidity. The composite membrane containing 0.2 wt.% s‐CNT increases proton conductivity approximately 45% at 120 °C and 50% relative humidity and enhances the tensile strength by about 1.3 times compared to the pristine membrane. However, the proton conductivity and water absorption shows a decline when more than 0.2 wt.% s‐CNT is added in the composite membrane, due to the aggregation of the s‐CNT, which serves as a proton barrier. For the single cell test, the developed composite membrane with 0.2 wt.% s‐CNT exhibits a notable performance for high temperature PEMFC.     

改性聚苯胺膜的气体分离性能及应用

论述了改性聚苯胺膜的气体透过性能。提出环取代聚苯胺膜由于自由体积增加而具有较大的透气系数。聚苯胺与聚酰亚胺预聚体的共混膜显示了比聚酰亚胺膜和聚苯胺膜更大的渗透系数,而分离系数介于二者之间。苯胺共聚物与乙基纤维素共混膜应用于空气分离,能将空气中氧体积分数从21％提高到46％,且具有中等的富氧空气流量和很好的稳定性,在医疗保健等领域具有很大的应用潜力。     

聚3,4-乙烯二氧噻吩/聚苯胺复合材料的制备与性能

以过硫酸铵(APS)和FeCl3为复合氧化剂,采用原位化学氧化聚合法合成了导电聚3,4-乙烯二氧噻吩/聚苯胺(PEDOT/PANI)复合材料,研究了苯胺浓度及加入时间、复合氧化剂配比和复合乳化剂配比对复合材料性能的影响,并对复合材料进行了分析. 结果表明,PEDOT/PANI复合材料合成的较佳工艺条件为：3,4-乙烯二氧噻(EDOT) 0.6 mol/L、复合氧化剂 0.6 mol/L(FeCl3:APS=1:2, mol)、复合乳化剂 0.4 mol/L(SDBS:CTAB=2:3, mol)、复合掺杂剂1.2 mol/L(H2SO4:SSA=4:1, mol)及苯胺0.8 mol/L, EDOT聚合2 h后加入苯胺溶液继续反应8 h. 复合材料的导电性、结晶性和热稳定性比纯导电聚合物好.     

乳酸掺杂聚苯胺／PP 树脂复合材料

乳液聚合法聚合乳酸掺杂聚苯胺。再使用开炼机混炼PP/聚苯胺,最后平板硫化仪得到永久抗静电聚苯胺/PP。研究发现,聚苯胺/PP复合材料的相容性好。通过掺杂,乳酸中解离出的H＋与聚苯胺分子链上的N原子结合,使聚苯胺获得永久、稳定的导电性。结果证明,随着聚苯胺的添加量,体积电阻减小三个数量级,冲击强度、拉伸强度和硬度足以满足很多应用的要求。