四氟乙烯-全氟甲基乙烯基醚共聚物的研究进展

作为可熔融加工且性能接近于聚四氟乙烯的全氟聚合物,PFA(四氟乙烯-全氟烷基乙烯基醚聚合物)得到了很快的发展并已形成了两个系列的商品.其中四氟乙烯-全氟丙基乙烯基醚共聚物(PFA-P)已经为人们熟悉,而另一类品种即四氟乙烯-全氟甲基乙烯基醚共聚物(PFA-M)却少有文献介绍.本研究对PFA-M的结构、性能、加工以及应用进行了综述.     

全氟磺酸树脂的熔融挤出加工性能及其离子交换膜的制备

用熔融挤出法制得不同厚度、表观平整密实的全氟磺酸离子交换膜(PFSIEM).利用热失重(TGA)、示差扫描量热分析(DSC)、毛细管流变仪、X射线衍射(XRD)研究了全氟磺酸树脂(PFSR)的热稳定性、熔体流变特征及挤出薄膜的结晶特性.实验表明:在400℃之前树脂热稳定性很好;全氟磺酸树脂熔体属假塑性流体,具有切力变稀特性,可以用熔融挤出法加工成膜;熔融挤出加工过程几乎没有改变树脂的结晶性能,挤出薄膜有一定的结晶度.研究了挤出机螺杆转速与三辊上光机线速度对薄膜成型性的影响,结果表明:当螺杆转速超过45 r/min时,PFSR不能塑化成型为薄膜;特定螺杆转速下,在一定范围内调节上光机线速度可制得厚度不同的薄膜.     

新型质子交换膜材料及其改性方法研究进展

综述了燃料电池用各种质子交换膜(PEM)材料及其改性方法．PEM材料包括全氟磺酸型离子交换树脂、聚苯并咪唑(PBI)、聚醚醚酮(PEEK)以及各种新型聚合物、嵌段共聚物等，而将这些材料制成PEM所采用的改性方法可分为磺化、酸基络合、杂化、共混、共聚、以及辐射接枝、等离子体等改性处理．还介绍了各种PEM材料的物性特点和PEM材料改性方法及其最新PEM研究报道．     

聚全氟乙丙烯中空纤维膜制备及其膜蒸馏过程*

以聚全氟乙丙烯(FEP)为成膜聚合物, 采用熔融纺丝-拉伸法制备FEP中空纤维膜, 研究了后拉伸倍数对FEP中空纤维膜结构与性能的影响。结果表明, 初生FEP中空纤维膜结构较为致密, 拉伸后出现微孔结构。随着拉伸倍数的提高膜的孔隙率和氮气通量明显增大, 而液体渗透压(LEP)有所降低。将所得FEP中空纤维膜用于减压膜蒸馏(VMD)研究, 并将其与常规熔融纺丝-拉伸法聚丙烯(PP)中空纤维膜比较。结果表明, 所得FEP中空纤维膜的疏水性能、液体渗透压力和力学强度均优于PP中空纤维膜。较强的疏水性能使其稳定运行而不被液体渗透, 脱盐率稳定在99%以上。同时, FEP中空纤维膜具有较大的内径(0.74 mm), 在保证较高脱盐率前提下可采用内压式减压膜蒸馏, 且真空膜蒸馏通量随着进料温度的升高显著增高。     

回收全氟辛酸的研制和应用

通过对聚四氟乙烯生产废水中全氟辛酸回收方法的研究 ,制得外观好、直链含量高、反应活性好的回收全氟辛酸 ,应用于生产效果良好     

一种新型引发剂的合成及其在制备全氟封端F30树脂中的应用

合成了一种全氟二辛酰基过氧化物引发剂,并首次将该引发剂应用到三氟氯乙烯和乙烯二元共聚体系,得到了三氟氯乙烯和乙烯(ECTFE)共聚物树脂一全氟封端F30树脂,并对其进行了表征.     

Viton氟橡胶品级发展简况

五十年代以来,出现了许多耐高温耐油的弹性体,其中量大面广,使用最多的是26类氟橡胶,它是由偏氟乙烯——全氟丙烯二元和三元(第三单体为四氟乙烯)组成的共聚弹性体。美国杜邦公司生产的Viton胶可     

四氟乙烯-丙烯共聚氟橡胶

四氟乙烯—丙烯共聚氟橡胶,是日本旭硝子公司用独自的技术,研制成功了从原料单体、聚合、直至硫化全过程的新氟橡胶。聚合物的结构与硫化配方与过去的氟橡胶不同,在特性上也是独特的。一、结构四氟乙烯—丙烯共聚氟橡胶的结构,如图1所示。四氟乙烯和丙烯的单体几乎呈现     

文摘

成型和烧结中不能再用的聚四氟乙烯废料可经高能辐照转化为高质量的氟碳原料和材料——细聚四氟乙烯粉末、C_6～C_(14)全氟烷烃和烯烃。所得的全氟碳化合物几乎没有CF_3侧基。这些全氟烯烃随后可简单而     

两种磁性液体用氟碳表面活性剂性能的实验研究

氟碳表面活性剂作为一种新型功能材料,具有优良的耐热稳定性和化学稳定性,耐高温、耐酸碱、耐腐蚀等特性,具有高表面活性、用量少、有效率高等卓越特点,通过对2种氟碳表面活性剂：全氟聚醚油（FMY）和全氟聚醚酸（FMS）与其它碳氢类和有机硅类的表面活性剂在表面张力的测量,表面张力随温度的变化,复配张力变化以及粘温性能测试等几个方面进行实验,得出其最佳使用条件,从而为制备氟碳基磁性液体确定制备工艺条件。     

真空紫外线对聚合物材料表面的影响

针对航天需要。研究了聚四氟乙烯(PTFE)和聚脂(PET)在真空紫外线(VUV)作用下的表面层变化。发现在所采用的射流式真空紫外线源的辐照作用下。聚四氟乙烯和聚脂颜色变成黑褐色。而且对表面的X光电子能谱(XPS)分析发现辐照后材料表面发生碳的富集。热失重分析发现辐照后样品失重增大。     

Preparation of microstructure-controllable superhydrophobic polytetrafluoroethylene porous thin film by vacuum thermal-evaporation

The three-dimensional porous network polytetrafluoroethylene (PTFE) thin films were achieved by a vacuum technique through evaporating the pure PTFE powders. The surfaces of PTFE thin films showed various morphologies by adjusting the evaporation temperature and the corresponding contact angle ranging from 133° to 155°. Further analyses of surface chemical composition and morphology by FTIR and FE-SEM revealed that the origin of hydrophobicity for the PTFE thin films could be ascribed to the fluorine-containing groups and the surface morphologies, indicating that abundant -CF₂ groups and network structures with appropriate pore sizes played a vital role in superhydrophobicity. By characterization of UV-Vis, the films also showed high transmittance and antireflection effect. The films prepared by this simple method have potential applications such as waterproof membrane and self-cleaning coating.     

A novel patterning technique using super-hydrophobic PTFE thin films by Cat-CVD method

Super-hydrophobic poly-tetrafluoroethylene (PTFE) films, with a water contact angle of over 160°, are formed by catalytic chemical vapor deposition (Cat-CVD) under high catalyzer temperature or pressure. Hydrophobicity of the PTFE films is maintained even after annealing up to 300 °C. We demonstrate a novel method for forming metal lines using super-hydrophobic PTFE films. Water-based functional liquid containing silver nanoparticles dropped on the patterned PTFE film localizes only on hydrophilic regions, resulting in formation of metal lines after annealing up to 150 °C.     

Determination of Selected Perfluorinated Acids (PFCAs) and Perfluorinated Sulfonates (PFASs) in Food Contact Materials Using LC‐MS/MS

Perfluorinated compounds, including perfluorinated acids and perfluorinated sulfonates, are environmentally persistent. These compounds are commonly used in consumer products as stain/water/grease repellents in carpets and clothing, in cooking utensils as nonstick coating and in food contact materials as a coating. This paper explores the potential application of liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS) system for the measurement of selected perfluorinated acids and perfluorinated sulfonates in three different brands (A, B and C) of food contact materials, including wrapping papers, breakfast bags, baking papers and roasting bags. In this study, the highest contents of selected perfluorinated acids were identified for the breakfast bag samples (2.54–6.60 pg/cm²), especially for B and C brands with the concentration of 6.60 and 5.35 pg/cm², respectively, while the lowest content was noted in roasting bag samples (0.27–0.40 pg/cm²). The contents of perfluorinated sulfonates were inversed as compared with those of perfluorinated acids. The highest contents of selected perfluorinated sulfonates were found in roasting bag samples (1.38–5.17 pg/cm²), especially for B brand. The analysed perfluorinated sulfonates were not detected in any of the breakfast bag samples. The highest content of perfluorinated compounds were reported for B brand food contact materials. The data indicate a risk of food contamination by perfluorinated compounds from the commonly used food contact materials. Copyright © 2015 John Wiley & Sons, Ltd.     

Fabrication of PTFE thin films by dual catalytic chemical vapor deposition method

Dependence of catalyzing materials on deposition of polytetrafluoroethylene (PTFE = ”Teflon” in commercial) films by catalytic chemical vapor deposition (Cat-CVD) method is investigated. It has been clarified that Ni-containing catalyzers has a catalyzing effect that can decompose hexafluoropropylene-oxide (HFPO) to form PTFE films. A novel method named Dual Cat-CVD is also proposed. In the method, carbonized and fluorinated surface of Ni-containing catalyzer is removed and refreshed using atomic hydrogen generated by additionally introduced tungsten (W) catalyzer in the same chamber. This Dual Cat-CVD method enables to recover the deposition rate of PTFE films drastically.     

聚四氟乙烯微孔膜及其无机粒子共混膜的结构及性能

以聚乙烯醇(PVA)为成膜载体,由聚四氟乙烯(PTFE)分散乳液制得PTFE微孔膜,通过对不同烧结温度的研究得出PTFE烧结模型,在烧结初期有利于PTFE形成微孔结构.在成膜体系中引入纳米无机粒子,得到PTFE/无机粒子共混平板膜.研究了无机粒子对共混膜结构及性能的影响,结果表明PTFE与碳酸钙(CaCO_3)粒子的粘结性差,在烧结成型过程中PTFE基质相与CaCO_3产生界面相分离形成微孔,形成的界面微孔不同于PTFE双向拉伸产生的纤维-结点状裂隙孔结构.共混膜经适当拉伸后孔隙率显著提高.     

粘结剂对块状极板碳纳米管双电层电容器性能影响研究

碳纳米管具有良好的导电性和合适的双电层形成区,适于制作双电层电容器极板． 不同粘结剂的使用会影响电容器的性能,分别选用酚醛树脂和聚四氟乙烯（ＰＴＦＥ）作为碳纳米 管极板的粘结剂,在有机电解质溶液中,研究其电容性能与比表面积和极板结构的关系,从而 找出合适的碳纳米管极板粘结剂．     

Matrix-Assisted Pulsed Laser Evaporation of polythiophene films

Organic poly-conjugated systems have recently attracted great interest as semi-conducting materials and, among poly-conjugated systems, substituted polythiophenes have given relevant results in PVs applications. The high conductivity required is affected by both the polymer conjugation length and the chain packing. Thus, highly region-regular polymers must be used and deposited as thin films with some technique which favours orientation and crystallization of the polymer chains.A deposition technique often used for its flexibility and high control over film characteristics is Pulsed Laser Deposition (PLD). In PLD, largely applied for inorganic thin film deposition, the material is ablated from a solid target by a focused pulsed laser beam and is deposited on the substrate placed at a small distance. Although some addition polymers have been successfully deposited the deposition seems to proceed via a “depolymerization-monomer ablation-repolymerization” mechanism, this is clearly not possible in general for organic molecules and condensation polymers.On the contrary MAPLE (Matrix-Assisted Pulsed Laser Evaporation) is a recently developed PLD based thin film deposition technique, particularly well suited for organic/polymer thin film deposition. Up to now MAPLE depositions have been carried out mainly by means of modified PLD systems, using excimer lasers operating in UV, but use of less energetic radiations can minimize the photochemical decomposition of the polymer molecules.We have used a deposition system explicitly designed for MAPLE technique connected to a Q-switched Ng:YAG pulsed laser which can be operated at different wavelength ranging from IR to UV in order to evaluate the effect of the choice of laser radiation on the deposition of POOPT thin films.From DRIFT-IR spectroscopy, all deposited films showed structural order; it was determined that the better wavelength for POOPT deposition is 532 nm. With this value of the laser wavelength the local chemical structure of the polymer was retained and the film appeared more homogeneous.     

Free Volume Changes in γ-Irradiated Polyethylene and Polytetraflourethylene

1. IntroductionPolymers, though very useful in daily life, arestructurally complicated materials. Their chemical nature and structural specificity are not clearlyunderstood yet. As a structural sensitive probe,positrons have been applied to detect the microscopic free-volume in polymer solids and films[1'2].In polymers, several mechanisms of positron annihilation are possible, e.g. pick--off annihilation ofortho-positronium (o--Ps), self~annihilation of parapositronium (p-Ps), annihilation of…     

PEMFC膜电极电催化层的制备和性能

膜电极催化层的组成和电催化剂的活性对质子交换膜燃料电池的性能有很大影响．采用浸渍还原法制备出了Pt平均粒径为3．1nm的Pt／C催化剂．催化剂中Pt的粒径和在碳黑载体（VulcanXC-72）表面的分散程度采用透射电镜（TEM）进行测试．用Pt／C催化剂、适量的Nation溶液和PrFE乳液制备出质子交换膜燃料电池（PEMFc）膜电极的催化剂层,并研究了该催化剂层中PTFE含量对其性能的影响．实验表明,PTFE强烈的疏水性可以迫使部分水分向阳极反扩散,催化层中加入适量的PTFE可以使膜电极具有一定的水管理能力,在去掉辅助增湿系统的条件下具有良好的极化性能．