Preparation and applications of novel fluoroalkyl end-capped oligomers/calcium carbonate nanocomposites

Calcium chloride reacted with sodium carbonate in the presence of a variety of self-assembled molecular aggregates formed by fluoroalkyl end-capped acrylic acid, 2-methacryloyloxyethane sulfonic acid, dimethylacrylamide, and acryloylmorpholine oligomers in aqueous solutions to afford the corresponding fluorinated oligomers/calcium carbonate composites in excellent to moderate isolated yields. These fluorinated calcium carbonate composites thus obtained were shown to have a good dispersibility not only in water but also in traditional organic media including fluorinated solvents. Dynamic light scattering measurements (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that these fluorinated composites are nanometer-size-controlled particles and well dispersed in these media. Cross-linked fluoroalkyl end-capped acrylic acid co-oligomer containing poly(oxyethylene) units was also applied to the preparation of new cross-linked fluorinated calcium carbonate nanocomposites under similar conditions. The obtained cross-linked fluorinated calcium carbonate nanocomposites were found to have an extremely higher dispersibility in aqueous and organic media including fluorinated solvents, compared to that of the corresponding fluoroalkyl end-capped oligomer nanocomposites. In particular, it was verified that these fluorinated calcium carbonate nanocomposites are applicable to the dispersion above poly(methyl methacrylate) (PMMA) film surface. Interestingly, field-emission SEM (FE-SEM) images of the cross-section of the modified PMMA films showed that calcium carbonate particles dispersed into these PMMA films could be arranged regularly above the modified film surface. More interestingly, cross-linked fluorinated oligomeric aggregates were able to provide suitable host moieties for the crystallization of calcium carbonate.     

Novel highly fluorinated sulfamates: synthesis and evaluation of their surfactant properties

Two synthetic pathways have been elaborated to prepare new series of highly fluorinated sulfamates with excellent yields. Surface tension measurements at the air/water interface showed that these compounds constitute new excellent non-ionic surfactants exhibiting high surface activity in the range of the best non-ionic fluoro surfactants already described in the literature. The most important feature of this work is that, in comparison with the classical non-ionic fluoro surfactants, these sulfamates are easily synthesized in a monodisperse form from classical and relatively non-toxic starting materials. The critical micelle concentration (CMC), the maximum surface excess concentration (Γ) and the minimum area per molecule (a) have been calculated from the surface tension measurements on surfactant aqueous solutions. Relationships have been established between the length of both the fluorinated tail and hydrocarbon spacer linking the hydrophobic tail to the hydrophilic head, and the interfacial properties.     

Novel fluorinated polyimides derived from 9,9-bis(4-amino-3,5-difluorophenyl)fluorene and aromatic dianhydrides

Novel fluorinated polyimides (PIs) were prepared from 9,9-bis(4-amino-3,5-difluorophenyl)fluorene with three aromatic dianhydrides via a one-step high-temperature polycondensation procedure. These obtained PIs showed excellent solubility and could be readily soluble in a variety of organic solvents such as NMP, DMAc, DMF, CHCl₃, CH₂Cl₂ and THF. All the PIs could afford flexible and strong films with low dielectric constants (2.62-2.79 at 1 MHz) and low moisture absorptions (0.18-0.41%). Thin films of these PIs exhibited high optical transparency and light color, with the cutoff wavelength at 341-355 nm and transmittance higher than 80% at 450 nm. Meanwhile, these PIs possessed eminent thermal stability, with decomposition temperatures (T_d) above 570 °C in both air and nitrogen atmospheres and glass transition temperatures (T_g) beyond 376 °C. Moreover, these fluorinated PI films showed low surface free energy and hydro-oleophobic character. The contact angles on the films for water and glycerol were in the range of 102.3-107.9° and 94.0-100.3°, respectively. In comparison with the analogous PI non-containing fluorine group, these fluorinated PIs showed better solubility, higher optical transparency, lower dielectric constants and lower surface free energy.     

Synthesis, characterization and properties of a novel fluorinated polyurethane

A novel fluorinated polyurethane (FPU) was prepared by fluorinated polyether glycol (PTMG-g-HFP) as a soft segment, 1,6-hexamethylene diisocyanate (HDI) or toluene diisocyanate (TDI) as a hard segment and 1,4-butanodiol (BDO) as a chain extender. Fourier transform infrared spectroscopy (FTIR), ¹H NMR, ¹³C NMR and gel permeation chromatography (GPC) were used to characterize the structure of the fluorinated polyurethane. The thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by thermogravimetric analysis (TGA). X-ray photoelectron spectroscopy (XPS) analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. And the mechanical properties of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were also measured. Chemical resistance of polyurethane films was estimated through spot tests with different solvents. The results showed that FPU had high thermal stability, strain-hardening property and good chemical resistance. The XPS measurements showed the fluorine enrichment on the surface of FPU.     

Preparation and applications of a variety of fluoroalkyl end-capped oligomer/hydroxyapatite composites

A variety of fluoroalkyl end-capped oligomers were applied to the preparation of fluorinated oligomer/hydroxyapatite (HAp) composites (particle size: 38-356 nm), which exhibit a good dispersibility in water and traditional organic solvents. These fluoroalkyl end-capped oligomer/HAp composites were easily prepared by the reactions of disodium hydrogen phosphate and calcium chloride in the presence of self-assembled molecular aggregates formed by fluoroalkyl end-capped oligomers in aqueous solutions. In these fluorinated HAp composites thus obtained, fluoroalkyl end-capped acrylic acid oligomers and 2-methacryloyloxyethanesulfonic acid oligomer/HAp nanocomposites afforded transparent colorless solutions toward water; however, fluoroalkyl end-capped N,N-dimethylacrylamide oligomer and acryloylmorpholine oligomer were found to afford transparent colorless solutions with trace amounts of white-colored HAp precipitants under similar conditions. HAp could be encapsulated more effectively into fluorinated 2-methacryloyloxyethanesulfonic acid oligomeric aggregate cores to afford colloidal stable fluorinated oligomer/HAp composites, compared to that of fluorinated acrylic acid oligomers. These fluorinated oligomer/HAp composites were applied to the surface modification of glass and PVA to exhibit a good oleophobicity imparted by fluorine. HAp formation was newly observed on the modified polyethylene terephthalate film surface treated with fluorinated 2-methacryloyloxyethanesulfonic acid oligomers and acrylic acid oligomer/HAp composites by soaking these films into the simulated body fluid.     

含氟高分子/SiO_2杂化疏水材料的制备及涂层表面性质

采用自由基溶液聚合与溶胶-凝胶法相结合的方法制备了含氟高分子/SiO2杂化疏水材料.通过甲基丙烯酸十二氟庚酯(FA)与乙烯基三乙氧基硅烷(VTES)共聚合成了含氟硅共聚物(PFAS),进一步通过原硅酸乙酯(TEOS)与PFAS共聚物溶液共水解缩聚制备了具有含氟侧基的碳碳主链高分子和硅氧网络的含氟高分子/SiO2杂化疏水材料.研究结果表明,SiO2组分含量提高可以显著增加杂化材料薄膜的涂敷厚度,改善其耐久性能,而对杂化材料疏水性能的影响不大.     

Fluorinated siloxane-containing waterborne polyurethaneureas with excellent hemocompatibility, waterproof and mechanical properties

Two series of polyurethaneurea (PUU) aqueous dispersions consisting of fluorinated siloxane segments were prepared from a high-molecular-weight (M_n = 8361) α,ω-dihydroxypoly[(3,3,3-trifluoropropyl)methylsiloxane] (PTFPMS), dimethylolpropionic acid, isophorone diisocyanate and ethylenediamine, with poly (tetramethylene oxide) and polycarbonate polyols as soft segments, respectively. These anionic aqueous dispersions were stable at the ambient temperature for more than 6 months, with particle sizes ranging from 45 to 98 nm. Both series of PUU films showed the excellent waterproof properties, i.e. the decrease in water absorption and surface energy upon the incorporation of PTFPMS segments. The phase mixing increased in the fluorinated siloxane-containing polyether-based PUUs and the phase separation increased first then decreased in the fluorinated siloxane-containing polycarbonate-based PUUs, with increasing PTFPMS content. All the PTFPMS-modified PUU films showed excellent mechanical properties. The polycarbonate-based PUU film consisting of 5 wt.% PTFPMS had a tensile strength of 60.7 MPa and a breaking elongation of 632%, owing to the increase in the ordered hydrogen bonding degree and the microphase-separation degree between the hard and soft segments in the system. In vitro hemolysis and dynamic clotting time measurements indicated that the thromboresistance was enhanced markedly with increasing PTFPMS content for both series of PUUs, which could be ascribed to the synergistic effect between the carboxylate groups and the PTFPMS segments migrating onto the surfaces of the films.     

核壳型含氟丙烯酸酯共聚物的合成及性能

采用饥饿态半连续种子乳液聚合方法, 在十二烷基硫酸钠(SDS)/辛基苯基聚氧乙烯醚(TX-10)复合乳化剂的作用下, 分别选用甲基丙烯酸三氟乙酯(TFEM)、甲基丙烯酸六氟正丁酯(HFBM)和甲基丙烯酸十二氟庚酯(DFHM)为含氟单体, 合成以丙烯酸正丁酯(BA)、甲基丙烯酸甲酯(MMA)和含氟单体为原料的核壳型结构含氟丙烯酸酯共聚物乳液. FTIR, 1H NMR, TEM和DSC分析结果显示, 获得了BA/MMA/含氟单体的共聚物乳液, 且乳液具有明显的核壳结构. DSC, TGA和SEM-EDX的分析显示, 核壳型结构的共聚物具有优异的热力学稳定性能和成膜性能; 长侧链或短侧链含氟单体对共聚物的热稳定性影响不明显, 但侧链较长的含氟单体所获得的聚合物在成膜过程中更易向表面迁移, 更能体现含氟聚合物的优点.     

Use of fluorinated maleimide and telechelic bismaleimide for original hydrophobic and oleophobic polymerized networks

The syntheses of original fluorinated maleimide and telechelic bismaleimide bearing C₆F₁₃ and C₆F₁₂ groups, respectively, and their use as reactive additives in photopolymerizable formulations of telechelic poly(propylene glycol) bismaleimide (PPGBMI) are presented. Fluorinated maleimide was synthetized in five steps in 63% overall yield from C₆F₁₃C₂H₄I precursor, whereas the fluorinated bismaleimide was prepared in six steps in 14% overall yield from IC₆F₁₂I. These latter led to fluorinated azido and diazido intermediates that were reduced into the fluorinated amine and diamines in two steps. The condensation of amine and diamine onto maleic anhydride offered an amic acid and a diamic acid, which were subsequently cyclized into fluorinated maleimide and bismaleimide. Formulations of telechelic PPGBMI containing a low concentration of these fluorinated maleimide and bismaleimide were UV cured and the surface properties of the resulting films were investigated. A deep modification of the surface properties was noted when the monomaleimide was used. In all the cases, a selective enrichment of the fluorinated monomer at the film surface was observed. The dependence of the surface properties on the fluorinated maleimide and bismaleimide concentrations were also studied, and showed an asymptotic behavior of the contact angle with only 1.5 wt % of fluorinated maleimide additive, whatever the conditions. This monomaleimide led to better hydrophobic and oleophobic properties of the resulting material than that containing the telechelic one. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3214–3228, 2008     

One-pot three-component reaction of C60, amino acid and fluorinated benzaldehyde to C60-pyrrolidine derivatives

A series of fluorinated 2,5-disubstituted C₆₀-pyrrolidine derivatives were synthesized via one-pot three-component reaction of C₆₀, amino acid and fluorinated benzaldehyde under reflux in toluene or microwave irradiation. The cis- and trans-isomers could be isolated by chromatography and fully confirmed by ¹H NMR.     

Synthesis and characterization of copolymers based on styrene and partially fluorinated acrylates

Copolymers of styrene and fluorinated acrylate monomers with F-octylalkyl, F(CF₂)₈(CH₂)_n^′ side groups were prepared by free radical polymerization. Thermal behaviour of the resulting polymers was investigated by DSC and TGA. Even if at the macroscopic scale the polymers surfaces are homogeneous and clear, the analysis indicates that all samples exhibit two glass transitions temperatures. This discontinuity may be regarded as an indication for microphase separation of fluorine-rich and polystyrene-rich microphases. Water and hexadecane contact angles measurements show that these polymers are quite surface active in the solid state. Surface and bulk organizations were investigated by XPS analysis. A strong correlation between bulk organization and surface properties of the polymers could be established. Preferential adsorption of fluorinated segments at the material surface were more pronounced than expected in the bulk.     

Use of telechelic fluorinated diiodides to obtain well-defined fluoropolymers

Different methods of synthesis involved in the preparation of fluorinated telechelics (or ,ω-difunctional compounds) from ,ω-diiodoperfluoroalkanes for obtaining well-defined fluoropolymers are described. This review focuses on molecules in which fluorinated chains are located on the backbone and not in a lateral position. First, a bibliographical approach develops the syntheses of ,ω-diiodoperfluoroalkanes (1) either by chemical transformations of telechelic derivatives or by telomerisation of fluoroolefins with molecular iodine or diiodoperfluoroalkanes. Then, fluorotelechelics are synthesised by means of four different processes: (a) by the chemical change in the presence of metalic salts; (b) from the bismonoaddition of 1 to ω-functional unsaturated derivatives; (c) from the bis(monoethylenation) of 1 followed by difunctionalisation (e.g., nucleophilic substitution); (d) from the coupling reactions between 1 and -iodo-ω-functional reactants. Finally, this review describes how several well-defined fluoropolymers can be produced from these fluorinated telechelics. Their specific chemical, physical and thermal properties are discussed with regard to modern industrial requirements.     

Langmuir isotherm analysis of novel branched per-fluorinated surfactants and their interactions with single stranded DNA

The efficient synthesis and surface properties of new fluorinated gemini surfactants are described. The aim of this study was to investigate the relationships between the molecular structure and the Langmuir layer properties of these fluorinated gemini lipids. The electrostatic ssDNA binding interactions of amino groups included on the spacer were also investigated. The synthesis corresponds to the substitution of vinyl fluorine atom of fluoro-unsaturated esters by a diethylene-oxide diamine via a Michael addition followed by a fluoride elimination reaction. For the spread layers, the measurements of surface pressure versus molecular area were performed with or without ssDNA in the subphase. The monolayers characteristics depend on the hydrophobic chain length, the polar-head, the pH of the subphase and the flexibility of the spacer. The introduction of ssDNA in the subphase seems to show a low interaction between the surfactants and the oligonucleotide.     

Synthesis and properties of novel fluorinated epoxy resins based on 1,1-bis(4-glycidylesterphenyl)-1-(3′-trifluoromethylphenyl)-2,2,2-trifluoroethane

A novel fluorinated epoxy resin, 1,1-bis(4-glycidylesterphenyl)-1-(3′-trifluoromethylphenyl)-2,2,2-trifluoroethane (BGTF), was synthesized through a four-step procedure, which was then cured with hexahydro-4-methylphthalic anhydride (HMPA) and 4,4′-diaminodiphenyl-methane (DDM). As comparison, a commercial available epoxy resin, bisphenol A diglycidyl ether (BADGE), cured with the same curing agents was also investigated. We found that the BGTF gave the exothermic starting temperature lower than BADGE no mater what kind of curing agents applied, implying the reactivity of the former is higher than the latter. The fully cured fluorinated BGTF epoxy resins have good thermal stability with glass transition temperature of 170-175 °C and thermal decomposition temperature at 5% weight loss of 370-382 °C in nitrogen. The fluorinated BGTF epoxy resins also showed the mechanical properties as good as the commercial BADGE epoxy resins. The cured BGTF epoxy resins exhibited improved dielectric properties as compared with the BADGE epoxy resins with the dielectric constants and the dissipation factors lower than 3.3 and dissipation 2.8 × 10⁻³, respectively, which is related to the low polarizability of the C-F bond and the large free volume of CF₃ groups in the polymer. The BGTF epoxy resins also gave low water absorption because of the existence of hydrophobic fluorine atom.     

Surface and bulk properties of severely fluorinated carbon fibres

The development of ultra-inert composites using fluorinated carbon fibres as the reinforcement requires fluorinated carbon fibres with a durable surface composition. Here we report the effect of direct fluorination using an F₂/N₂ mixture at 653 K on the surface and bulk properties of two types of high strength carbon fibres. These were treated up to a surface fluorine content of ∼64 at.% and a bulk fluorine content of ∼15 mass%. A colour change was observed after fluorination caused by the changes in the graphitic band structure of the carbon fibres by the introduction of carbon sp³ hybridisation. The tensile strength and Young's modulus decrease after fluorination by up to 33 and 22%, respectively. XRD shows marginal changes in the interlayer distance but the crystallite size increases. Changes in the electrical conductivity of the fluorinated carbon fibres indicate that the modification is confined to the near surface volume. Predominantly covalent C-F bonds are formed as shown by X-ray photoelectron spectroscopy (XPS) and measured zeta (ζ)-potentials. Hence the fluorinated fibres are hydrophobic and have low surface tensions. This and the large increase in fibre surface area, as determined by nitrogen adsorption, is expected to facilitate interfacial interaction between fluorinated carbon fibres and fluoropolymers.     

含氟聚酰亚胺及其在微电子工业中的研究进展I含氟单体及聚酰亚胺的合成

综述了近年来国内外在含氟聚酰亚胺(PI)研究及应用领域中的最新进展情况。主要从含氟二胺单体、二酐单体及含氟聚酰亚胺在合成方面的研究进展情况进行了详细的综述。重点阐述了中国科学院化学研究所305组近几年在这方面的研究进展情况，并指出为了推动含氟聚酰亚胺这类具有优良综合性能的功能材料在工业上的广泛应用，就必须首先解决含氟单体种类较少这个制约含氟聚酰亚胺发展的瓶颈问题。     

Synthesis and characterization of fluorinated polyurethane with fluorine-containing pendent groups

A novel fluorinated polyurethane （FPU） with fluorine-containing pendent groups was prepared by using fluorinated polyether glycol （PTMG-g-HFP） as a soft segment, 1,6-hexamethylene diisocyanate （HDI） or toluene diisocyanate （TD1） as a hard segment and 1,4-butanodiol （BDO） as a chain extender. FTIR, ^1H NMR, ^13C NMR and GPC were used to characterize the structure of the fluorinated polyurethane. Thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by TGA. XPS analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. The results showed the fluorine enrichment on the surface of FPU.     

Influence of fluorinated acids bonding on surface properties of crosslinked epoxy-based polymers

Two series of crosslinked fluorinated epoxy-based materials containing variable fluorine contents (from 0 to 6 wt.% F) were prepared using formulations based on a fluorinated acid (FA), epoxy monomer and a diamine. The epoxy monomer was based on diglycidyl ether of bisphenol A (DGEBA) while the curing agent was propyleneoxide diamine (Jeffamine D-230). The selected FA were: 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptanoic acid (FA1), perfluoro-heptanoic acid (FA2), and perfluoro-nonanoic acid (FA3). One of the series synthesized, FA-DGEBA/Jeffamine, is characterized by covalent attachment of the FA to the polymer by an ester bond. The other series, FA-Jeffamine/DGEBA, is characterized by ionic interaction between FA and polymer chains. The influence on thermal and surface properties of the architecture and chain-length of FA, and the nature of the linkage between FA and network precursors, was analyzed and discussed. It was found that both series showed high oleophobicity, but depending on the linkage between the fluorinated acid and the network, it was possible to develop hydrophobic or hydrophilic materials. The fluorine enrichment with the perfluoroalkyl substitutions was proved by XPS. By this technique it was possible also to analyze the concentration of ammonium groups at the surface.     

Preparation and properties of waterborne epoxy resin modified by poly(meth)acrylates containing long fluorinated side chains

Abstract

Two waterborne poly(meth)acrylates containing fluorinated side chains (PALF and PASF) were synthesized by conventional radical copolymerization. Then waterborne epoxy composites with hydrophobic surface were obtained through a phase-inversion emulsion technique, using the PALF and PASF acrylates as reactive surface additives. Contact angle measurements and X-ray photoelectron spectroscope were employed to characterize the surface properties and the results confirmed that the fluorine atoms in the longer fluorinated side chains migrated to the outmost layer more efficiently. The effect of the fluorinated content and the length of the fluorine side chain on thermal and bulk properties of the waterborne epoxy resin was investigated. With increasing the fluorinated content or the length of the fluorine side chain, the contact angles and thermal properties improved while the mechanical properties showed no deterioration.     

Preparation of fluoroalkyl end-capped oligomers/magnetite nanocomposites possessing a good dispersibility and stability

Fluoroalkyl end-capped vinylphosphonic acid cooligomers-encapsulated magnetite nanocomposites were prepared by the magnetization of aqueous ferric and ferrous ions in the presence of the corresponding fluorinated cooligomers and magnetic nanoparticles under alkaline conditions. These fluorinated cooligomers magnetic composites are nanometer size-controlled very fine particles and have a good dispersibility and stability in water and traditional organic solvents. These fluorinated nanocomposites were also applied to the surface modification of poly(methyl methacrylate) to exhibit a good oleophobicity imparted by fluorine on their surface. Fluoroalkyl end-capped 2-methacryloyloxyethanesulfonic acid oligomer-encapsulated magnetite nanocomposites and fluoroalkyl end-capped 2-acrylamide-2-methylpropanesulfonic acid oligomer-encapsulated magnetite nanocomposites were prepared in good isolated yields by the magnetization of iron chlorides in the presence of the corresponding oligomers and magnetic nanoparticles under similar conditions. Colloidal stability of these fluorinated nanocomposites thus obtained in water was demonstrated to become extremely higher than that of fluorinated vinylphosphonic acid cooligomers/magnetic nanocomposites.