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1.
New perfluoroalkylated acrylic monomers with a biphenyl core and hydrocarbon spacer (CH2)m of various length (m = 0, 6, 11) were synthesized from biphenol. Phase transitions of monomers and intermediates isolated in the course of the synthesis were studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Whereas most fluoroacrylic monomers and low molecular weight precursors displayed thermotropic behavior (whatever the length of the spacer), the polymers did not retain the ability to form mesophases. Moreover, the bulk organization of the fluorinated side groups was diminished strongly for polymers in comparison with the corresponding fluorinated monomers. Nevertheless, it was demonstrated that an intermediate length of the spacer (-CH2)6, could favor the organization of the rigid perfluoroalkylated biphenyl side groups in the bulk.  相似文献   

2.
A series of polyacrylate monomers with F‐alkylalkyl [F(CF2)n(CH2)n] side groups were prepared by free‐radical polymerization. The effect of the chemical structure on the surface properties of poly(ethylene terephthalate)s was evaluated by variations in the relative length of the fluorocarbon and hydrocarbon units in the side group. The resulting polymers were quite surface‐active in the solid state. The surface and bulk organization was investigated by X‐ray photoelectron spectroscopy analysis. A strong correlation between the bulk organization and surface properties of the polymers was established. The outmost layer, formed from trifluoromethyl groups and some ester functions, suggests that the side chain is arranged irregularly in the polymer–air interface. The length of the lateral chain governs this organization: long fluorinated chains and short hydrocarbon spacers are essential elements of the molecular design for such low‐surface‐energy materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3737–3747, 2005  相似文献   

3.
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.  相似文献   

4.
The commercial hyperbranched aliphatic polyols (Hn) were modified by thioglycolic acid (TA) and hexafluorobutyl acrylate (HFBA) or dodecafluoroheptyl methacrylate (DFHMA) to prepare a series of fluorinated hyperbranched polyesters. For comparison, a linear fluorinated polymer, poly(n-BMA-co-DFHMA), was synthesized through the copolymerization of n-butyl methacrylate (BMA) and DFHMA. The molecular structures were characterized by 1H NMR spectroscopic analysis. The synthesized polymers were incorporated into UV-curable formulations as additives, and exposed to a UV lamp. After UV curing, the wettability of the films was investigated by contact angle measurement with water and 1-bromonaphthalene. The results showed that both the hydrophobicity and oleophobicity were greatly enhanced. Moreover, the fluorinated hyperbranched polymers possessed better water and oil repellency than the copolymer poly(n-BMA-co-DFHMA) at a very low concentration. The surface F/C ratio values of the cured films were detected by XPS analysis, and the film with TAH20-DFHMA showed the highest F/C ratio value, indicating its most efficient aggregation effect at the film surface.  相似文献   

5.
Polymers with fluoroalkyl side-groups on three of every four carbon atoms along the polymer main chain were made by treating 1 : 1 copolymers of perfluoroallyl (or methallyl)ethers and maleic anhydride with SF4, and then esterifying the resulting acid fluoride groups with 1H, 1H-pentadecafluorooctanol. Surface wettability of these polymers by polar and non-polar liquids was studied. The critical surface tension (γc) was found by Zisman's method. The dispersion force component of polymer surface energy (γsD) and the polar component of surface energy (γsp) were calculated by the respective methods of Fowkes and Owens. The γc values for several of the highly fluorinated polymers were lower than previously reported for any fluoropolymer but not so low as has been observed for the surface of an oriented perfluoroacid monolayer. In the range 11.4–18.5 dyne/cm, γc approximates γsD for the fluorinated surfaces; however at lower γc values, considerable difference between γc and γsD was noted.  相似文献   

6.
A series of new Ba-based coordination polymers (CPs) were mechanochemically synthesized by milling Ba-hydroxide samples with perfluorinated and fluorine-free benzene-dicarboxylic acids, including tetrafluoroisophthalic acid (H2mBDC-F4), tetrafluorophthalic acid (H2oBDC-F4), isophthalic acid (H2mBDC) and phthalic acid (H2oBDC). The new fluorinated CPs: [Ba(mBDC-F4)·0.5H2O] (1) and [Ba(oBDC-F4)·1.5H2O] (2) are compared to their nonfluorinated counterparts: [Ba(mBDC)·2.5H2O] (3), and [Ba(oBDC)·1H2O] (4). These materials are thoroughly characterized using powder X-ray diffraction. The products obtained by milling are all hydrated but vary in their water contents. Compositions and local structures are investigated by elemental analysis, thermal analysis, MAS NMR and attenuated total reflection-infrared spectroscopy. These materials exhibit high thermal stabilities but small surface areas that remain unchanged even after thermal treatments.  相似文献   

7.
Radical polyaddition of bis(α-trifluoromethyl-β,β-difluorovinyl) terephthalate [CF2C(CF3)OCOC6H4COOC(CF3)CF2] (BFP) with diformylalkanes to produce fluorinated polymer bearing ketone-carbonyl groups in main chain is described. The radical additions of hexanal, pentanal and benzaldehyde with 2-benzoxypentafluoropropene [CF2C(CF3)OCOC6H5] were examined as model reactions to yield the corresponding addition product with hexanal and pentanal in high yields, and no product with benzaldehyde. The addition of acyl and hydrogen was found to take place to perfluoroisopropenyl group. The results of the model reactions suggested that the reaction might be applicable to polyaddition to produce polymers with diformylalkanes. The results of polyaddition of BFP with glutaraldehyde under the emulsion polymerization condition showed that the polymer of Mn=4.8×103 was obtained in fairly high yields. This might be a novel preparation method of polymers bearing fluorinated polyketone structure.  相似文献   

8.
In order to synthesize poly-(fluorinated alkanesulfonamides) a series of model experiments were carried out: (1) reactions of fluorinated alkanesulfonyl fluorides with amines, (2) reactions of fluorinated alkanesulfonyl chloride with amines and (3) reactions of sodium salts of fluorinated alkanesulfonamides with alkyl iodides of fluorinated alkanesulfonic acid esters. Seventeen new fluorinated alkanesulfonamides were prepared in good yields, namely: RFO(CF2)2SO2NR1R2 (1a-h), R1R2NSO2RFSO2NR1R2 (2a-h) and [Cl (CF2)4O(CF2)2SO2NH(CH2)3]2 (3). Reaction of RFSO2NH2 with equivalent amount of NaOCH3 and methyl iodide was shown to give both the N-mono- and N,N-di-substituted amides. Consequently the N-monosubstituted alkanesulfonamides were chosen as monomers for syntheses of the poly-(fluorinated alkanesulfonamides) and two new polymers were synthesized. The effect of the condition of the polycondensation on M?n of the polymers were discussed and elemental composition, 19F NMR, IR, M?n, Tg, tensile strength, thermal and chemical stabilities of the polymers were measured. Several new perfluoroalkanesulfonyl chlorides CISO2RFSO2Cl (4a-c) and fluorinated alkanesulfonic acid esters (6a-d) were synthesized. However, reaction of CFCl2CF2O(CF2)2SO2F with AlCl3 was found to give Cl3CCF2O(CF2)2SO2F (5) instead of the expected sulfonyl chloride.  相似文献   

9.
Highly fluorinated polymers are promising materials in separation methods due to their combination of high chemical and thermally stability, hydro‐ and oleophobicity, and weak intermolecular forces. However, application of these polymers in chromatography is limited because of their low solubility in aqueous‐organic solvents. In our research, the highly fluorinated water soluble polymers with –SO3N(Et)4+, –SO2NH2, and –N(Et)2 terminal groups were synthesized and applied as additives to the background electrolyte for the separation of steroid hormones and proteins by capillary electromigration methods. It is shown that highly fluorinated polymers can be used both as pseudo‐stationary phases in electrokinetic chromatography for high separation efficiency (N  ∼ 200 × 103) and selectivity (α    1.1) of uncharged analytes (e.g., steroid hormones), and as dynamic modifiers of fused silica capillary walls. The highest separation efficiency (∼ 1 × 106) and selectivity (α  ∼ 1.3) of steroid hormones was achieved by combination of sodium dodecyl sulfate and fluoropolymer with sulfonate groups in background electrolyte with pH 2. Dynamic wall coatings based on fluoropolymer with –SO2NH2 (which are easier and faster to create and wash off) exhibit significantly higher separation efficiency and selectivity compared to capillary electrochromatography on capillary columns based on polymethacrylate polymers.  相似文献   

10.
Most research on copolymers with fluorinated monomers has focused on the relationship between fluorinated monomer content and the corresponding surface structure. However, the influence of the non-fluorinated block on the surface structure of the copolymer film is unknown. Various molecular weight poly(butyl methacrylates) (PBMA) end-capped with 2-perfluorooctylethyl methacrylate (FMA) units (PBMA-ec-FMA) have been synthesized by atom transfer radical polymerization (ATRP). The effect of the PBMA block length on the surface structure and properties of the polymers both in the solid state and in solution was investigated using various techniques. X-ray photoelectron spectroscopy (XPS), sum frequency generation (SFG) vibrational spectroscopy and X-ray diffraction (XRD) analyses indicated that longer PBMA blocks enhanced both the enrichment of the fluorinated moieties and the order of the packing orientation of the perfluoroalkyl side chains on the surface. This enhancement was attributed mainly to the molecular aggregate structure of the end-capped polymers with long PBMA blocks in the solution and to the interfacial structure at the air/liquid interface, which favors the -(CF2)7CF3 moieties self-assembling on the polymer surface during film formation. This observation suggests that the polyacrylate block structure in fluorinated diblock copolymers, in addition to the fluorinated monomer content, plays an important role in structure formation on the solid surface.  相似文献   

11.
Progress toward the preparation of porous organic polymers (POPs) with task‐specific functionalities has been exceedingly slow—especially where polymers containing low‐oxidation phosphorus in the structure are concerned. A two‐step topotactic pathway for the preparation of phosphabenzene‐based POPs (Phos‐POPs) under metal‐free conditions is reported, without the use of unstable phosphorus‐based monomers. The synthetic route allows additional functionalities to be introduced into the porous polymer framework with ease. As an example, partially fluorinated Phos‐POPs (F‐Phos‐POPs) were obtained with a surface area of up to 591 m2 g?1. After coordination with Ru species, a Ru/F‐Phos‐POPs catalyst exhibited high catalytic efficiency in the formylation of amines (turnover frequency up to 204 h?1) using a CO2/H2 mixture, in comparison with the non‐fluorinated analogue (43 h?1) and a Au/TiO2 heterogeneous catalysts reported previously (<44 h?1). This work describes a practical method for synthesis of porous organic phosphorus‐based polymers with applications in transition‐metal‐based heterogeneous catalysis.  相似文献   

12.
The story of the outset and the growth of radical polyaddition of bisperfluoroisopropenyl derivatives [CF2?C(CF3)? R? C(CF3)? CF2] with several organic compounds possessing carbon–hydrogen bonds is described. The reaction afforded novel fluorinated polymers bearing such organic segments in polymer main chains as 1,4‐dioxane, diethyl ether, dimethoxyethane, 18‐crown‐6, triethylamine, glutaraldehyde, and alkanes which have never been supposed as direct starting compounds for preparation of polymers. The facile method for preparation of fluorinated hybrid polymers bearing alkylsilyl groups was developed with diethoxydimethylsilane and silsesquioxanes. Taking advantage of the high reactivity of the perfluoroisopropenyl group as a radical acceptor, self‐polyaddition and cyclopolymerization were investigated. Triethysilyl perfluoroisopropenyl ether [CF2? C(CF3)? O? Si(C2H5)3] was proved to be the most probable candidate for self‐polyaddition. Cyclopolymerization of perfluoroisopropenyl vinylacetate [CF2?C(CF3) OCO? CH2CH? CH2] was investigated to afford polymers possessing five‐membered‐ring units in main chains. The interconversion of the unstable fluorinated carbon radical and the stable hydrocarbon radical had an important role in the reaction. The radical addition reaction presented herein may be developed for preparation of a wide variety of novel fluorinated polymers and organic compounds possessing functional groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4101–4125, 2004  相似文献   

13.
Radical addition of 2-benzoxypentafluoropropene [CF2C(CF3)OCOC6H5] (BPFP) with alcohols such as ethanol and 2-propanol was investigated to afford fluorinated alcohols. Radical addition of BPFP with cyclic ethers such as tetrahydrofuran, 1,3-dioxolane and tetrahydropyran was also achieved to afford addition products followed by hydrolysis to yield fluorinated alcohols possessing cyclic structures. Novel fluoroalkyl acrylates and methacrylates were synthesized from the fluorinated alcohols with (meth)acryloyl chlorides. Radical polymerization of the fluoroalkyl (meth)acrylates yielded polymers of 1.2 × 105 as the highest molecular weight.  相似文献   

14.
Several new side‐chain liquid crystalline (LC) polysiloxanes and elastomers ( IP ‐ VIP ) bearing fluorinated mesogenic units and crosslinking mesogens were synthesized by a one‐step hydrosilylation reaction with poly(methylhydrogeno)siloxane, a fluorine‐containing LC monomer 4′‐undec‐10‐enoyloxy‐biphenyl‐4‐yl 4‐fluoro‐benzoate and a crosslinking LC monomer 4′‐(4‐allyloxy‐benzoxy)‐biphenyl‐4‐yl 4‐allyloxy‐benzoate. The chemical structures and LC properties of the monomers and polymers were characterized by use of various experimental techniques such as FTIR, 1H‐NMR, EA, TGA, DSC, POM and XRD. The effect of crosslinking mesogens on mesomorphic properties of the fluorinated LC polymers was studied as well. The obtained polymers and elastomers were soluble in many solvents such as toluene, tetrahydrofuran, chloroform, and so forth. The temperatures at which 5% weight loss occurred (Td) were greater than 250°C for all the polymers, and the weight of residue near 600°C increased slightly with increase of the crosslinking mesogens in the fluorinated polymer systems. The samples IP , IIP , IIIP and IVP showed both smectic A and nematic phases when they were heated and cooled, but VP and VIP exhibited only a nematic mesophase. The glass transition temperature (Tg) of polymers increased slightly with increase of crosslinking mesogens in the polymer systems, but the mesophase–isotropic phase transition temperature (Ti) and smectic A–nematic mesophase transition temperature (TS‐N) decreased slightly. It suggests that the temperature range of the mesophase became narrow with the increase of crosslinking mesogens for all the fluorinated polymers and elastomers. In XRD curves, the intensity of sharp reflections at low angle decreased with increase of crosslinking mesogens in the fluorinated polymers systems, indicating that the smectic order derived from fluorinated mesogenic units should be destroyed by introduction of more crosslinking mesogens. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

15.
The high-pressure and high-resolution NMR cell method has been developed for precise measurements of supercritical carbon dioxide solutions. 19F NMR chemical shifts of a series of fluorinated benzenes, C6H n F m (n = 6 ? m and m = 1 ~ 6) in CO2 at dilute concentrations were measured over a wide pressure range up to 35 MPa at 314.3 K. The density dependence of the corrected chemical shift, where the bulk magnetic susceptibility contribution was subtracted, was well represented by a cubic function of CO2 density for any fluorinated benzene. The linear coefficients, arising from pairwise intermolecular interactions, were found to be dependent on the numbers and positions of fluorine atoms in the fluorinated benzenes. The solute–solvent interaction between fluorine and CO2 was discussed.  相似文献   

16.
Two bulk samples of one and the same or of different amorphous polymers were brought into contact and held for a chosen period of time at a constant healing temperature (T) over the interval of T from below the bulk glass transition temperature (T g bulk) by ~50 °C to above T g bulk by ~10 °C. As formed adhesive joints were shear-fractured in tension at room temperature, and lap-shear strength (σ) was measured as a function of T. It has been found that σ develops with T as logσ?~?1/T both at symmetric and asymmetric interfaces of polystyrene, poly (methyl methacrylate) and poly (2,6-dimethyl-1,4-phenylene oxide). This behaviour implies that there is no discontinuity in the evolution of σ when going through T g bulk, and that this process is controlled by one and the same diffusion mechanism both below and above T g bulk. The results obtained indicate that the contact layer of the polymers investigated is in the viscoelastic state at T well below T g bulk and support the concept of a decrease in the T g of a near-surface layer with respect to T g bulk.  相似文献   

17.
The waterborne fluorinated polyurethane–acrylate hybrid emulsion (WFPUA) was prepared by two steps, including the preparation of the fluorinated alcohol blocked polyurethanes (FBPU) in the mixtures of vinyl monomers and fluorinated monomers and then the free radical polymerization after the pre-emulsification of the said system. The effects of hydrophilic monomer (MDEA) on the surfactivity and the emulsifiability of the FBPU were firstly reported. Then, the particle size (d), zeta potential (ζ), and viscosity (η) of the WFPUA hybrid emulsion were characterized, respectively. At the same time, the surface properties and the mechanical properties of the films were investigated. The results show that the increase of MDEA is good for the emulsifiability and the lower surface tension of the FBPU. This increase improves the stability, the ζ and η, yet decreases the d of the WFPUA emulsion. However, it has disadvantages to the hydrophobic performance of the WFPUA films. When the content of the MDEA in the WFPUA is increased from 4.67 to 14.89 %, the surface free energies are increased from 22.22 to 27.28 mJ m?2 and the attenuation rate of the contact angle–time curve is increased from 0.3051° to 0.6290°/min. Also, with the increase of MDEA, the tensile strength and the shore hardness of the film are increased, but its elongation at break is decreased. The storage moduli of the film are enhanced remarkably. Meanwhile, the glass transition temperature of the soft segment [Tg(s)] is reduced and that of the hard segment [Tg(h)] is raised.  相似文献   

18.
Several fluorinated and chlorofluorinated acrylates and methacrylates were synthesized from the alcohols RFCH2OH with RF=CCl3, CHClCH2CCl3, (CF2CFCl)nCl, (C2F4)nH, CF3, C7F15 and C6F13CH2. The corresponding polymers were also studied for their application as transparent polymeric materials. For this purpose the refractive indices n20D of the monomers and the polymers were measured as were the Tg values of the polymers. A study of their infrared spectra shows to what extent these products could be utilized taking into consideration their absorption in the long wavelength range between 0.85 and 1.50 m. The refractive indices of these polymers, which are reduced when increasing the number of fluorine atoms in the molecule, and that of the Tg measured between 50 and 70° C for the fluorinated methacrylates, indicate a potential use of these polymers as sheathing materials for optical fibres.  相似文献   

19.
A series of new chiral side-chain liquid crystalline polymers (P1–P7) have been synthesized with poly(methylhydrogeno)siloxane, two chiral liquid crystalline monomers, cholesteryl-4-allyloxybenzoate (M1) and cholesteryl 4-(10-undecylen-1-yloxy) benzoate (M2), and a nematic liquid crystalline monomer, 4-(trifluoromethyl)phenyl 4-(undec-10-enoyloxy)benzoate (M3). The chemical structures and liquid crystalline properties of the synthesized polymers have been investigated by FTIR, 1H-NMR, differential scanning calorimetry (DSC), polarizing optical microscopy (POM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). All chiral polymers show wide mesophase temperature ranges and a high thermal stability with decomposition temperatures (T d) at 5 % weight loss greater than 300 °C. P1–P4 display a single cholesteric phase, but P5–P7 containing more fluorinated units show a smectic A (SA) phase besides a cholesteric phase. The optical properties of the polymers have been characterized by circular polarization spectra and optical rotation analysis. The cholesteric polymers P3 and P4 exhibit different colors at room temperature, and the color can remain over 24 months. The maximum reflection bands of polymers P1–P4 shift to long wavelength with increasing the content of M3 in the polymer systems. For P5–P7, the reflection wavelengths change sharply around the temperature of the SA–Ch phase transition. The specific rotation value of P2 smoothly decreases from ?8.2° to ?0.29° when it is heated, but the specific rotation value of polymer P7 changes from negative value to positive value on heating cycle. The optical properties of the polymers offer tremendous potential for various optical applications.  相似文献   

20.
Several new structures of fluorinated polymers poly(1)-poly(9) were prepared by free radical ring opening polymerization of vinylcyclopropane monomers 1-9 containing different fluorinated side groups of the type (CH2)n(CF2)pF. While in poly(1)-poly(3) p varied from 6 to 10 for a fixed n=2, in poly(4)-poly(6) n increased from 3 to 5 at the given p=8. In poly(7) and poly(8) a phenyl ring was incorporated to elongate the mesogenic side group (n=2; p=6 and 8, respectively), that was further separated from the polymer backbone by a methylene spacer (m=11) in poly(9). Therefore, the effects of various chemical variations of the polymer structure on the mesophase behavior could be assessed. The polymers were in fact co-polymers comprising both 1,5-linear and cyclobutane-ring isomer units. In any case they formed smectic mesophase(s) owing to the special character of the perfluorinated chains. The order and the isotropization temperature (Ti) of the mesophase were enhanced by increasing p, but Ti lowered with increasing n. Extension of the side group by insertion of a phenyl ring improved Ti. Wide angle X-ray diffraction studies clarified the nature of the different smectic phases, the occurrence of which was discussed in terms of the ability of the fluorinated side groups to pack antiparallel in either a partly or fully interdigitated structure. Co-polymers of 3 with a non-mesogenic, not fluorinated co-monomer 10 were also prepared with different chemical compositions. Co-polymerization was found to be another effective means of modifying the mesophase behavior of the poly(vinylcyclopropane)s.  相似文献   

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