含氟橡胶的研究进展及在航空发动机中的应用

综述了含氟橡胶材料的研究进展和其在航空发动机领域的应用现状。对比了氟橡胶、氟醚橡胶、全氟醚橡胶和氟硅橡胶的耐介质、耐热和低温性能,论述了常用含氟橡胶牌号的适用工况和在航空发动机上的典型应用。指出研发高性能含氟橡胶新品种、构建含氟橡胶标准体系、累积疲劳、老化、寿命等性能数据、健全考核验证方法和充分贯彻适航要求是未来航空发动机含氟橡胶材料和制品的发展方向。     

高性能特种弹性体的拓展（四）——氟橡胶（2）

综述近年来在非轮胎橡胶制品领域拓展应用的具有特殊性能和特种用途、能在苛刻条件下使用的高性能特种弹性体。本综述第4部分介绍氟橡胶的发展历程和分类,详述在通用氟橡胶（1型和2型氟橡胶）基础上拓展的高性能氟橡胶的组成和特性。这些高性能氟橡胶包括高氟含量氟橡胶、过氧化物硫化氟橡胶、耐低温氟醚橡胶（3型氟橡胶）[全氟甲基乙烯基醚（PMVE）基氟醚橡胶和全氟甲氧基甲基乙烯基醚（MOVE）基氟醚橡胶]、耐极端环境全氟醚橡胶、耐碱氟橡胶[四氟乙烯/丙烯二元共聚氟橡胶（四丙氟橡胶）、四氟乙烯/乙烯/PMVE和四氟乙烯/丙烯/偏氟乙烯三元共聚氟橡胶（4型氟橡胶）、四氟乙烯/六氟丙烯/偏氟乙烯/乙烯/PMVE五元共聚氟橡胶（5型氟橡胶）、四氟乙烯/四氟丙烯二元共聚氟橡胶（6型氟橡胶）]。本文报道在高性能氟橡胶领域国内外的研发信息,重点介绍高性能氟橡胶在我国获得的新进展。     

高性能特种弹性体的研究进展 ——氟橡胶（1）

综述近年来在非轮胎橡胶制品领域拓展应用的具有特殊性能和特种用途、能在苛刻条件下使用的高性能特种 弹性体。本综述第4部分介绍氟橡胶的发展历程和分类,详述在通用氟橡胶（1型和2型氟橡胶）基础上拓展的高性能氟橡 胶的组成和特性。这些高性能氟橡胶包括高氟含量氟橡胶、过氧化物硫化氟橡胶、耐低温氟醚橡胶（3型氟橡胶）[全氟甲 基乙烯基醚（PMVE）基氟醚橡胶和全氟甲氧基甲基乙烯基醚（MOVE）基氟醚橡胶]、耐极端环境全氟醚橡胶、耐碱氟橡胶 [四氟乙烯/丙烯二元共聚氟橡胶（四丙氟橡胶）、四氟乙烯/乙烯/PMVE和四氟乙烯/丙烯/偏氟乙烯三元共聚氟橡胶（4型 氟橡胶）、四氟乙烯/六氟丙烯/偏氟乙烯/乙烯/PMVE五元共聚氟橡胶（5型氟橡胶）、四氟乙烯/四氟丙烯二元共聚氟橡 胶（6型氟橡胶）]。本文报道在高性能氟橡胶领域国内外的研发信息,重点介绍高性能氟橡胶在我国获得的新进展。     

高性能特种弹性体的研究进展（四） ——氟橡胶（续完）

综述近年来在非轮胎橡胶制品领域拓展应用的具有特殊性能和特种用途、能在苛刻条件下使用的高性能特种 弹性体。本综述第4部分介绍氟橡胶的发展历程和分类,详述在通用氟橡胶（1型和2型氟橡胶）基础上拓展的高性能氟橡 胶的组成和特性。这些高性能氟橡胶包括高氟含量氟橡胶、过氧化物硫化氟橡胶、耐低温氟醚橡胶（3型氟橡胶）[全氟甲 基乙烯基醚（PMVE）基氟醚橡胶和全氟甲氧基甲基乙烯基醚（MOVE）基氟醚橡胶]、耐极端环境全氟醚橡胶、耐碱氟橡胶 [四氟乙烯/丙烯二元共聚氟橡胶（四丙氟橡胶）、四氟乙烯/乙烯/PMVE和四氟乙烯/丙烯/偏氟乙烯三元共聚氟橡胶（4型 氟橡胶）、四氟乙烯/六氟丙烯/偏氟乙烯/乙烯/PMVE五元共聚氟橡胶（5型氟橡胶）、四氟乙烯/四氟丙烯二元共聚氟橡 胶（6型氟橡胶）]。本文报道在高性能氟橡胶领域国内外的研发信息,重点介绍高性能氟橡胶在我国获得的新进展     

全氟羧酸酯乙烯基醚的合成研究

全氟羧酸酯乙烯基醚用于多种含氟聚合物的改性,合成全氟羧酸离子交换树脂等高性能含氟聚合物,也可以合成含氟醚类的绿色可降解表面活性剂。采用3-羧酸甲酯全氟丙酰氟与六氟环氧丙烷进行加成反应,然后脱羧制备全氟羧酸酯乙烯基醚。     

高端有机氟材料关键技术研发取得突破

正近日,科技部高新司对863计划新材料技术领域支持的"高端有机氟材料关键技术研发"项目,在北京组织专家进行了验收。高端有机氟材料是新材料领域重要的发展方向之一,在航空、航天、医药、电子等领域有良好的应用前景,对传统材料产业技术升级有着重要意义。该项目围绕耐高/低温氟橡胶材料、基于聚偏乙烯和氟硅树脂的新型含氟涂料开展了三氟丙基二甲基硅烷基丙烯基醚、耐低温氟橡胶、全氟甲基乙烯     

含氟材料应用报告会及含氟材料科技情报交流会摘要

时间:198D.7.7.～7.12. 地点:上海市警备司令部第三招待所参加者数:85个单位,168位代表交流论文:44篇主办单位:国家科委新型化工材料专业组有机氟分组与中国化工学会。氟橡胶概况上海有机氟材料研究所任伟成介绍了目前已工业规模生产的偏氟乙烯—三氟氯乙烯、偏氟乙烯—全氟丙烯(或再有四氟乙烯的共聚弹性体、四丙氟橡胶、氟硅橡胶;中试规模生产的羧基亚硝基氟橡胶,氟化磷腈橡胶、全氟醚橡胶;研究中的弹性体氟硅氟碳杂链弹性体氟硅氟醚杂链弹性体,聚全氟烷     

高性能特种弹性体的拓展(四)——氟橡胶(1)

综述近年来在非轮胎橡胶制品领域拓展应用的具有特殊性能和特种用途、能在苛刻条件下使用的高性能特种弹性体.本综述第4部分介绍氟橡胶的发展历程和分类,详述在通用氟橡胶(1型和2型氟橡胶)基础上拓展的高性能氟橡胶的组成和特性.这些高性能氟橡胶包括高氟含量氟橡胶、过氧化物硫化氟橡胶、耐低温氟醚橡胶(3型氟橡胶)[全氟甲基乙烯基醚...     

高性能特种弹性体的拓展(四)——氟橡胶(续完)

综述近年来在非轮胎橡胶制品领域拓展应用的具有特殊性能和特种用途、能在苛刻条件下使用的高性能特种弹性体.本综述第4部分介绍氟橡胶的发展历程和分类,详述在通用氟橡胶(1型和2型氟橡胶)基础上拓展的高性能氟橡胶的组成和特性.这些高性能氟橡胶包括高氟含量氟橡胶、过氧化物硫化氟橡胶、耐低温氟醚橡胶(3型氟橡胶)[全氟甲基乙烯基醚...     

三种含氟橡胶的性能对比

研究了P457氟橡胶、VPL85540氟醚橡胶、PFR 95HT全氟醚橡胶三种生胶的性能及其混炼胶的硫化特性、低温性能、力学性能、耐热空气老化性能、耐介质性能、压缩永久变形性能等。结果表明,相同配方及工艺下,三种含氟橡胶材料由于生胶分子结构不同,性能上存在较大差异。VPL85540氟醚橡胶低温性能最佳,力学性能最差;PFR 95HT全氟醚橡胶在耐高温老化和耐介质方面表现最佳,低温性能最差。在压缩永久变形方面,低于200℃时P457氟橡胶和VPL85540氟醚橡胶的表现优于PFR 95HT全氟醚橡胶;高于250℃时,PFR 95HT全氟醚橡胶由于大分子优异的耐高温性能,其高温压缩永久变形最低。     

Fluoropolymer synthesis in supercritical carbon dioxide

Herein we review the environmentally friendly synthesis of fluorinated polymers in supercritical carbon dioxide (scCO₂). Historically, many high-performance fluorinated materials are commercially synthesized in aqueous media using fluorinated surfactants or in non-aqueous conditions using fluorinated solvents. Our group has pioneered both the homogeneous and heterogeneous polymerization of fluorinated monomers in scCO₂. This review includes discussions on the synthesis of main-chain and side-chain fluoropolymers conducted via a chain-growth or continuous process. Specific materials consist of acrylate- and styrene-based systems, poly(vinyl ether)s, tetrafluoroethylene- and vinylidenefluoride-based, as well as novel fluorinated elastomers and thermoplastics.     

Fluoropolymer Fibres: Physicochemical Nature and Structural Dependence of their Unique Properties, Fabrication, and Use. A Review

Fluorine-containing fibre-forming polymers, fibres, and fibre materials have unique properties due to the presence of fluorine atoms. Totally fluorinated polymer materials are distinguished by the highest resistance to all kinds of chemical reagents and physically active media, low wettability by polar liquids, and other specific functional properties. In examining the physicochemical nature of the unique properties of fluoropolymer fibres and fibre materials with respect to the theory of chemical structure and D. I. Mendeleev's Periodic Table of the Elements, we found that they are due to the features of the fluorine atoms, which have the highest electronegativity of all elements, high ionization energy, high energies of bonds with carbon atoms, and simultaneously shield the molecular chain from external effects. Fibre-forming fluoropolymers, fibres, and fibre materials made from them have high resistance to external effects, biostability and bioinertness, and highly effective protective and other functional characteristics. This relates to the totally fluorinated materials PTFE, HFP, and CP-TFE-HFP to the greatest degree. Fibres and fibre materials based on totally fluorinated polymers (PTFE, HFP, CP-TFE-HFP) are placed in a special group for use in articles utilized in extreme conditions in exposure to especially aggressive media and other external active effects where the use of other kinds of fibres and fibre materials is difficult or impossible because of their low stability and rapid destruction.     

Novel polystyrene bearing highly branched hexafluoropropene trimer pendants

A novel styrenic monomer having hexafluoropropene trimer on the benzene ring was prepared. The highly fluorinated monomer was polymerized to yield a white powdery polymer, which was soluble in fluorinated solvents and had resistance to usual organic solvents, good water repellency, and low refractivity. In contrast to common fluoropolymers having linear-fluorinated side-chains, the polymer has a characteristic high glass transition temperature. Thus, the fluorinated polymer and copolymer with styrene are suitable for applications at elevated temperature. The polymers can replace the conventional fluorinated polyacrylates, which are used in large quantity as repellents with potentially generating perfluorooctanoic acid in the environment.     

Towards new environmentally friendly fluoroelastomers: from facile chemical degradation to efficient photo‐crosslinkable reaction

Our objective is to develop a versatile and facile method that allows the synthesis of novel primary fluorinated co‐oligomers as precursors of photo‐crosslinkable networks. Transparent carboxyl‐terminated fluorinated co‐oligomers with molecular weights ranging between 2000 and 10 400 g mol^?1 were synthesized via facile degradation. The structural changes of fluorinated backbone were investigated using various analysis techniques. Then two major approaches, namely esterification and ring opening, were applied to obtain photochemical diacrylates (HEMA‐ and GMA‐IEM‐terminated co‐oligomers). These two precursors can be cured in 60 s under UV radiation without high temperature, high pressure or toxic solvent. The glass transition temperatures of HEMA‐ and GMA‐IEM‐terminated fluoropolymers at about ?20 °C, assessed from differential scanning calorimetry, showed an increase after crosslinking, and the glass transitions at 20 °C were no longer observed. These two crosslinked films were found to have higher decomposition temperatures, when compared to starting precursors. The contact angles on the surface of the two elastomer materials were only about 74° and 78°, which increased to 105° and 110° after UV irradiation. The tensile strength of the two cured fluoroelastomers can still reach 1.3 MPa at 200 °C. © 2019 Society of Chemical Industry     

Enhancement of the chemical resistance of nitrile rubber by direct fluorination

Nitrile rubber (NBR), poly(acrylonitrile‐co‐butadiene) or NBR packers, are used to seal oil‐well tubing, where they often come into contact with ZnBr₂ brines at high temperatures and pressures. Under these conditions, NBR exhibits accelerated chemical degradation, which results in embrittlement and cracking. Although alternative fluoropolymers exhibit excellent chemical resistance, their strength is less than NBR, and replacement of the usual gasket materials with fluoroelastomers is expensive. We have demonstrated that a fluoropolymer surface on a nitrile elastomer provides the necessary chemical resistance while the elastomer retains strength. This can be achieved by direct fluorination, a rather easy and inexpensive process. Samples of NBR O‐rings were fluorinated by exposure to F₂ and F₂/HF mixtures at various temperatures. Although fluorination by F₂ produced the desired fluoropolymer layer, fluorination by F₂/HF (hydrofluoric acid) mixtures gave a smoother fluorinated layer at lower temperatures and shorter reaction times. Elemental analysis showed that the fluorinated layer eliminated ZnBr₂ diffusion into the NBR polymeric matrix. Surface fluorination also significantly retarded the loss of the mechanical properties of NBR when it was exposed to zinc bromide fluid. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 971–979, 2003     

A new mechanism for increasing tear strength and cut-growth resistance of elastomers

A new mechanism is presented for increasing the tear strength of noncrystallizing elastomers over a broad temperature range. It is shown that the incorporation, into elastomers, of a plastic filler with the proper yield strength can substantially increase tear strength by decreasing the excess stress that develops at the tip of a sharp cut in an elastomer strip under tension. To be effective at low aspect (length/diameter) ratio, the yield strength of the plastic must be of the same order of magnitude as the tensile strength of the elastomer to which it is added. The analysis is strictly valid only for very small deformations, where crack-tip blunting can be ignored, and for an applied stress sufficiently low that the plasticyielding zone is very small relative to the crack length. It provides a useful model, at least, for the development of a new mechanism for increasing the tear strength of fluoroelastomers at sufficiently high temperatures, which is of significant practical importance. Examples of the use of a new fluoroplastic micropowder to provide over a fourfold increase in tear strength of several fluoroelastomers at high temperatures are given. © 1993 John Wiley & Sons, Inc.     

特种陶瓷的制备工艺综述及其发展趋势

本文主要介绍了粉末陶瓷原料的制备技术、特种陶瓷成形工艺、烧结方法以及未来的发展趋势。目前,特种陶瓷中的粉末冶金陶瓷工艺已取得了很大进展,但仍有一些面临急需解决的问题。当前阻碍陶瓷材料进一步发展的关键之一是成形技术尚未完全突破。压力成形不能满足形状复杂性和密度均匀性的要求。多种胶体原位成形工艺,固体无模成形工艺以及气相成形工艺有望促使陶瓷成形工艺获得关键性突破。     

PVC thermoplastic elastomers

The paper describes the development and properties of a new family of thermoplastic elastomers based on polyvinyl chloride. Comparisons of the new products with traditional flexible PVC's will be presented, pointing up differences in specific gravity, low temperature properties, heat resistance, melt viscosity, and general physical properties such as tensile modulus and elongation. The elastomeric properties of the new materials are explored and compared to some typical cured elastomers—chloroprene, chlorosulphonated polyethylene. The common thermoplastic elastomers based on block copolymers and polyurethanes are also considered in relation to the new compositions. Such properties as compression-set, flex and fatigue resistance, oil and chemical resistance, weatherability, and performance at elevated temperatures are detailed. The unique feature of this technology that allows one to tailor the surface characteristics from typically high PVC gloss to the fine dull satin finish of cured elastomers is discussed.     

含氟聚合物的研究进展

含氟聚合物因其具有优异的化学稳定性、耐热性、电绝缘性、自润滑性、不粘性、耐大气老化性等功能和特点,使其在工业的各个领域得到了广泛的应用。对近五年来含氟聚合物及含氟聚合物乳液的合成及表征的研究现状进行了综述。     

Poly(fluoroalkoxyphosphazenes)—versatile seal materials

Poly(fluoroalkoxyphosphazene) fluoroelastomers are members of a new family of polymers based on a phosphorous–nitrogen backbone. Physical property evaluation tests have demonstrated that these fluorelastomers possess excellent stress–strain properties, low-temperature flexibility, thermal stability, and resistance to a variety of demanding environments including synthetic lubricants, hydrocarbon fuels, and aqueous caustics. Their service temperature range is about ?60° ?200°C. Poly(fluoroalkoxyphosphazene) fluoroelastomers have shown the capability to function in severe dynamic applications; i.e., lip seals (1? in. I.D.) performed for >1000 hr at 5500 rpm in MIL L-7808G lubricant at 115°C. Also, O-ring seals successfully completed a 1000-hr dynamic qualification test over a temperature range of ?54°–163°C in a rod seal test apparatus. These elastomers can be used for seals, O-rings, gaskets, diaphragms, hose, and protective coatings.