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1.
A group of poly(N-vinylcarbazole) pendant polysulfones has been prepared by reacting it with benzene, toluene, p-chlorobenzene- and p-nitrobenzenesulfonyl chloride and N-methyl carbazole, 3,6-disulfonyl chloride by the Friedel Crafts reaction. Carbazole-based backbone polysulfones have also been prepared by the reaction of N-methyl carbazole, 3,6-disulfonyl chloride and biphenyl, naphthalene, anthracene, and carbazole in presence of anhydrous aluminum chloride. The various sulfone polymers, thus prepared, have been structurally characterized by elemental analysis and IR spectroscopy. Detailed analyses of thermal stability, dielectric, and conductivity characteristics have revealed certain significant differences between these two types of sulfone polymers.  相似文献   

2.
Cellulose derivatives containing long hydrocarbon side chains and the carbazole chromophore are prepared. N‐4′‐Bromobutylcarbazole is first synthesized from carbazole and 1,4‐dibromobutane. Alkylated carbazole is then reacted with cellulose acetate in dimethyl sulfoxide solution to produce cellulose ethers containing the desired chromophore. Polymers containing a mixture of alkyl side chains are also prepared by the subsequent addition of 1‐bromododecane to the reaction mixture. Characterization of the resulting cellulose derivatives by FTIR spectroscopy indicates that the deacetylation of cellulose acetate and the subsequent etherification are both complete. In addition, the incorporation of the carbazole chromophore is clearly shown by 1H‐ and 13C‐NMR spectroscopy. Polymers of different carbazole content, ranging from 2.9 to 1.1 chromophores per anhydroglucose repeat unit, are obtained by varying the reaction conditions. Substitution is found to be controlled primarily by the quantity of alkylating agent introduced while variation of the reaction time has little effect. This method is used to prepare (dodecyl)y(N‐4′‐carbazolylbutyl)xcellulose, (decyl)y(N‐4′‐carbazolylbutyl)xcellulose, and (butyl)y(N‐4′‐carbazolylbutyl)xcellulose. Cellulose acetate can be replaced by (methyl)cellulose as the starting material to obtain analogous products. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2764–2772, 1999  相似文献   

3.
The preparation of poly(5-nitroindole) (P5NI) coating was achieved on 316L-stainless steel (SS). Poly(5-nitroindole) was deposited via anodic oxidation of the corresponding monomer in acetonitrile (ACN) solution containing LiClO4. The influence of P5NI coating against SS corrosion was studied in 3.5% NaCl solution by electrochemical impedance spectroscopy (EIS), anodic polarization curves and the open circuit potential–time (Eocpt) diagrams. The results obtained suggest that P5NI coating forms a sacrificial layer but the efficiency against corrosion is limited with increasing time.  相似文献   

4.
Poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) can be crosslinked by quaternization to develop a positively charged dense network structure. According to this mechanism, PDMAEMA/polysulfone (PSF) positively charged nanofiltration membrane was developed by interfacial crosslinking polymerization using PSF plate microfiltration membrane as support layer, PDMAEMA aqueous solution as coating solution, and p‐xylylene dichloride/n‐heptane as crosslinking agent. Technique and condition of developing membrane such as concentration of coating solution, coating time, pH value of coating solution, content of low molecular weight additive in coating solution, concentration of crosslinking agent, crosslinking time, and number of coatings were studied. FTIR, SEM, and X‐ray photoelectron spectroscopy were used to characterize the structure of membranes. This membrane had rejection to inorganic salts in water solution, the rejection rate to MgSO4 (1 g/L water solution at 0.8 MPa and 30°C) was about 90%, and permeation flux was about 10–20 L m?2 h?1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2721–2728, 2004  相似文献   

5.
Poly(N-ethylaniline) (PNEA) coatings were grown by potentiodynamic synthesis technique on 304 stainless steel (SS) alloy from 0.1 M of N-ethylaniline (NEA) in 0.3 M oxalic acid solution. Characterization of adhesive and electroactive PNEA coatings was carried out by cyclic voltammetry, FT-IR spectroscopy and scanning electron microscopy (SEM) techniques. The protective properties of PNEA coatings on SS were elucidated using linear anodic potentiodynamic polarization, Tafel and electrochemical impedance spectroscopy (EIS) test techniques, in highly aggressive 0.5 M HCl and 0.5 M NaCl solutions. Linear anodic potentiodynamic polarization test results proved that PNEA coating improved the degree of protection against pitting corrosion in HCl and NaCl solutions. Tafel test results showed that PNEA coating appears to enhancement protection for SS in 0.5 M NaCl and 0.5 M HCl solutions. However, according to long-term EIS results, PNEA coating is better for the protection of SS electrodes during the long immersion period in NaCl compared to that in HCl medium.  相似文献   

6.
Polyethylene glycol (PEG) structures were deposited onto stainless steel (SS) surfaces by spin coating and argon radio frequency (RF)‐plasma mediated crosslinking. Electron spectroscopy for chemical analysis (ESCA) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) indicated the presence of  CH2 CH2 O structure and C C C linkage, as a result of the plasma crosslinking, on PEG‐modified SS surfaces. Scanning electron microscopy (SEM) indicated complete deposition, and water contact angle analysis revealed higher hydrophilicity on PEG‐modified surfaces compared to unmodified SS surfaces. Surface morphology and roughness analysis by atomic force microscopy (AFM) revealed smoother SS surfaces after PEG modification. The evaluation of antifouling ability of the PEG‐modified SS surfaces was carried out. Compared to the unmodified SS, PEG‐modified surfaces showed about 81–96% decrease in Listeria monocytogenes attachment and biofilm formation (p < 0.05). This cold plasma mediated PEG crosslinking provided a promising technique to reduce bacterial contamination on surfaces encountered in food‐processing environments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 485–497, 2005  相似文献   

7.
The poly(carbazole-co-pyrrole) copolymer was synthesized on TiO2 sol–gel precoated 304 stainless steel (TiO2) by cyclic voltammetry in tetrabutylammonium perchlorate containing acetonitrile solution. The synthesized coating was characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, and solid-state conductivity measurements. Corrosion protection behavior of the TiO2/poly(carbazole-co-pyrrole)-coated steel was evaluated by open circuit potential–time curves, potentiodynamic polarization, and electrochemical impedance spectroscopy methods. Corrosion test results showed that TiO2/poly(carbazole-co-pyrrole) composite film enhanced corrosion resistance of stainless steel up to 50 days of immersion in 0.1M HCl corrosive medium.  相似文献   

8.
Poly(pyrrole-co-N-methyl pyrrole) copolymer and poly(pyrrole)/poly(N-methyl pyrrole) bilayer composites were electrochemically synthesized on copper by cyclic voltammetry from aqueous solution of 0.3 M oxalic acid and 0.1 M monomer. Synthesis of copolymers were performed with different monomer feed ratios (pyrrole:N-methyl pyrrole, 8:2, 6:4, 5:5, 4:6 and 2:8) and in order to determine the copolymer, which has the best corrosion performance, anodic polarization was applied to copolymer coated samples. It was found that the performance of coatings was strongly dependent to the monomer feed ratio and the copolymer synthesized with 8:2 concentration ratio showed the most protective property compared to others. Bilayer of poly(pyrrole)/poly(N-methyl pyrrole) was also synthesized to compare the anticorrosive properties. Polymer films were characterized by ATR-FTIR spectroscopy and SEM techniques. Corrosion behavior of polymer composites was investigated in 0.1 M H2SO4 solution by anodic polarization and electrochemical impedance spectroscopy. Different approaches such as phase angle at high frequency and areas under Bode plots were used to evaluate corrosion performances of the coatings. Copolymer and bilayer coatings were found to have higher protection effect than single polypyrrole coatings. Moreover, bilayer coating exhibited better protection efficiency than copolymer coating against corrosion of copper when the obtained results were compared.  相似文献   

9.
Wei Ye  Fuhui Wang 《Electrochimica acta》2006,51(21):4426-4432
Nanocrystallized (NC) 309 stainless steel (309SS) coating has been fabricated on glass substrate by DC magnetron sputtering. The coating, with an average grain size less than 50 nm, had ferritic (bcc) structure rather than the austenitic (fcc) structure of the bulk steel. The electrochemical corrosion behavior of the NC coating and the bulk steel in solutions of 0.25 M Na2SO4 + 0.05 M H2SO4 and 0.5 M NaCl + 0.05 M H2SO4 was investigated by using potentiodynamic polarization, potentiostatic polarization and AC impedance techniques. The results showed that the corrosion behavior of the NC 309SS coating and 309SS bulk steel depended on the composition of the solutions. In the Na2SO4 solution there was only a little difference between the corrosion resistance of the passive films on the NC coating and the bulk steel. However, in the solution with chloride ions, the localized corrosion resistance of 309SS was greatly enhanced by nanocrystallization due to the formation of a compact and stable passive film on the NC coating. The electronic structure of the passive film formed on the NC coating and on the bulk steel was analyzed by means of capacitance measurements, and a corrosion mechanism is proposed.  相似文献   

10.
The influence of steel surface pretreatment with different types of iron–phosphate coatings on the corrosion stability and adhesion characteristics of polyester coatings on steel was investigated. The phosphate coating was chemically deposited either from the simple novel plating bath, or with the addition of NaNO2, as an accelerator in the plating bath. The morphology of phosphate coatings was investigated using atomic force microscopy (AFM). The corrosion stability of polyester coatings on steel pretreated by iron–phosphate coatings was investigated by electrochemical impedance spectroscopy (EIS) in 3% NaCl solution, while “dry” and “wet” adhesion were measured by a direct pull-off standardized procedure. It was shown that greater values of pore resistance, Rp, and smaller values of coating capacitance of polyester coating, Cc, on steel pretreated with iron–phosphate coating were obtained, as compared to polyester coating on steel phosphated with accelerator, and on the bare steel. The surface roughness of phosphate coating deposited on steel from the bath without accelerator is favorable in forming stronger bonds with polyester coating. Namely, the dry and wet adhesion measurements are in accordance with EIS measurements in 3% NaCl solution, i.e. lower adhesion values were obtained for polyester coating on steel phosphated with accelerator and on the bare steel, while the iron–phosphate pretreatment from the novel bath enhanced the adhesion of polyester coating on steel.  相似文献   

11.
《Ceramics International》2017,43(2):1731-1739
This study investigates the surface characteristics, in vitro biocompatibility and electrochemical behaviour of nanoporous niobium incorporated titanium dioxide (Nb-incorporated TiO2) coated 316L stainless steel (SS) for orthopaedic applications. The coating material was synthesized by sol-gel methodology and was deposited on 316L SS by using spin coating technique and heat treatment. The experimental conditions were optimized to obtain a coating with nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The analysis confirmed the formation of a crystalline nanoporous Nb-incorporated TiO2 coating with hydrophilic nature. Mechanical studies validated that the coating has excellent adhesion to the specimen and appreciable hardness value. In vitro bioactivity test confirmed that the nanoporous morphology of the coating facilitated enhanced hydroxyapatite (HAp) growth. Electrochemical studies established that the insulative nature of the coating provides excellent corrosion resistance to 316L SS.  相似文献   

12.
Poly((N-methacryloyloxymethyl)benzotriazole-co-N-vinylpyrrolidone) was synthesized by free radical solution polymerization technique and characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Thermal stability of the synthesized copolymer was analyzed by thermogravimetric analysis and differential thermal analysis. The corrosion performances of low nickel stainless steel specimens coated with different mole ratios of synthesized copolymer were investigated in 1 M H2SO4 using potentiodynamic polarization, electrochemical impedance method, and chronoamperometric studies. Surface and morphological investigation were also provided in order to characterize the adherence and uniformity of the coatings. Electrochemical corrosion test and surface analysis results were clearly showed that the copolymer-coatings served as a stable host matrix on low nickel stainless steel as environmentally favored good anticorrosive coating.  相似文献   

13.
The absorption, fluorescence excitation and emission spectroscopy, and time‐dependent spectrofluorimetry have been used to study the photophysics of copolymers of N‐vinylcarbazole with different monomers like vinyl acetate, methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate in dichloromethane. In all the copolymers and at different N‐vinylcarbazole content, the absorption spectra reflect only the monomer carbazole units. The two kinds of excited monomer species of N‐vinylcarbazole are present in S1 state. Short‐lived (~3 ns) excited monomer decays forming low energy excimer obtained by the complete overlap of the excited carbazole monomer. The long‐lived excited monomer (~8 ns) decays to ground state without formation of any excimer. The high energy excimer is relatively short‐lived and is formed by the partial overlap of the carbazole units. The presence of bulky group in the copolymer chain hinders the formation of excimers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 372–380, 2006  相似文献   

14.
To investigate the role of polyaniline (PANI) in the corrosion protection of stainless steel (SS) in oxygen-deficient acidic solution, a separate doped PANI film electrode on a glass substrate was prepared and the test solution (1 M H2SO4) was purged with high-purity N2 until dissolved oxygen level decreased more than two orders of magnitude. In this deaerated 1 M H2SO4 solution, the galvanic coupling interaction between the separate PANI film electrode and 410 SS was studied. Results reveal that the separate PANI film can passivate the 410 SS steadily for a long period of time. A variety of experimental methods including potentiodynamic measurement, potentiostatic (current-time) examination and X-ray photoelectron spectroscopy (XPS) are used to explore the mechanism by which the separate PANI film passivated the galvanic coupling SS in the deaerated sulfuric solution. These studies show that passivation is achieved because PANI film provides a large critical current at the early stage of coupling and a persistent passive current by its electrochemical dedoping/re-doping equilibrium activity with the acidic environment at the subsequent stage of coupling.  相似文献   

15.
The electrochemical synthesis of poly(indole‐co‐thiophene) copolymer coatings was achieved on low‐nickel stainless steel (LN SS) with the cyclic voltammetry technique using indole and thiophene monomers in acetonitrile medium containing lithium perchlorate. The optimization of synthesis parameters such as monomer feed ratio and various scan rates was studied and also their influence on the morphology of the copolymer coatings on LN SS. For the first time, a possible radical cationic electro‐copolymerization mechanism is also proposed in order to understand the electrochemical synthesis. The bonding and structure of the as‐synthesized coatings were characterized using Fourier transform infrared and 1H NMR spectroscopies. The surface morphology and composition of the coatings were also assessed using scanning electron microscopy and energy‐dispersive X‐ray analysis. It was observed that changes in morphology occurred which had a marked and significant effect on the electrochemical behaviour of the coated LN SS confirmed using electrochemical techniques of potentiodynamic polarization and electrochemical impedance spectroscopy in aqueous 0.5 mol L?1 H2SO4 solution. The obtained results revealed that the copolymer coatings on LN SS provided significant corrosion protection in the acid medium. It was also found that a 1:1 ratio of indole to thiophene yielded the most stable and corrosion‐protective copolymer coating. © 2013 Society of Chemical Industry  相似文献   

16.
We present the preparation of advanced antistatic and anticorrosion coatings of polystyrene (PS) incorporating a suitable amount of dodecylbenzenesulfonic acid (DBSA)‐doped SiO2@polyaniline (SP) core–shell microspheres. First, aniline‐anchored SiO2 (AS) microspheres that were about 850 nm in diameter were synthesized using the conventional base‐catalyzed sol–gel process with tetraethyl orthosilicate in the presence of N‐[3‐(trimethoxysilyl)propyl]aniline. SP core–shell microspheres were then synthesized by chemical oxidative polymerization of aniline monomers with ammonium persulfate as an oxidizing agent in the presence of the AS microspheres. The polyaniline shell thickness of the as‐prepared core–shell microspheres was estimated to be about 120 nm. The AS and SP microspheres were further characterized using Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy. The as‐synthesized DBSA‐doped SP core–shell microspheres were then blended into PS using N‐methyl‐2‐pyrrolidone as solvent and then cast onto a cold–rolled steel (CRS) electrode to obtain antistatic and anticorrosion coatings with a thickness of about 10 µm. The corrosion protection efficiency of the as‐prepared coating materials on the CRS electrode was investigated using a series of systematic electrochemical measurements under saline conditions. The enhanced corrosion protection ability of the PS/SP composite coatings may be attributed to the formation of a dense passive metal oxide layer induced by the redox catalytic effect of the polyaniline shell of the as‐synthesized core–shell microspheres, as evidenced by electron spectroscopy for chemical analysis and SEM observations. Moreover, the PS composite coating containing 10 wt% of the SP core–shell microspheres showed an electrical resistance of about 3.65 × 109Ω cm?2, which meets the requirements for antistatic applications. Copyright © 2012 Society of Chemical Industry  相似文献   

17.
A series of sol–gel derived organic–inorganic hybrid coatings consisting of organic poly (vinyl carbazole) (PVK) and inorganic silica (SiO2), with 3‐(trimethoxysilyl)propyl methacrylate (MSMA) as coupling agent, were successfully synthesized. First of all, vinyl carbazole (VCz) monomers are copolymerized with MSMA by performing free‐radical polymerization reactions with AIBN as initiator. Subsequently, as‐prepared copolymer (i.e., sol–gel precursor) was further reacted with various feeding content of tetraethyl orthosilicate (TEOS) through organic acid (CSA)‐catalyzed sol–gel reaction to form a series of PVK‐silica hybrid (PSH) sol–gel materials. The as‐synthesized hybrid materials were subsequently characterized by Fourier‐Transformation infrared (FTIR) spectroscopy and solid‐state 29Si NMR. It should be noted that the PVK‐SiO2 hybrid (PSH) coating on cold‐rolled steel (CRS) electrode with low silica loading (e.g., 10 phr) was found to be superior in anticorrosion property over those of neat PVK based on a series of electrochemical measurements such as corrosion potential, polarization resistance, corrosion current, and electrochemical impedance spectroscopy in 3.5 wt% NaCl electrolyte. The better anticorrosion performance of PSH coatings as compared to that of neat polymer may probably be attributed to the stronger adhesion strength of PSH coatings on CRS electrode, which was further evidenced by Scotch tape test evaluation. Increase of adhesion strength of PSH coatings on CRS electrode may be associated with the formation of Fe–O–Si covalent bonds at the interface of PSH coating and CRS electrode based on the FTIR–RAS (reflection absorption spectroscopy) studies. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers  相似文献   

18.
Surgical grade stainless steel (316L SS) is a widely used implant material in orthopedic surgeries. However, the release of metallic ions evidenced from the 316L SS implants in vivo conditions is a big challenge. In order to minimize the release of metallic ions, coating the 316L SS implant with a biocompatible material like hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is one of the suitable methods. In this paper, the hydroxyapatite coating on borate passivated through poly-ortho-phenylenediamine (PoPD)-coated 316L SS by a dip coating method has been reported. The coatings were characterized by electrochemical techniques such as potentiodynamic polarization, electrochemical impedance spectroscopy, and cyclic voltammetry. Surface characterization studies of the coatings such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were also carried out. The leach out characteristics of the coatings was determined at the impressed potential. The mechanical property of the coatings was evaluated by Vicker’s microhardness test. The Cr-rich passive film formed underneath the PoPD layer showed a higher protective efficiency. The ability to form apatite on the post-passivated PoPD-coated 316L SS specimen was examined by immersing it in the simulated body fluid. The enhanced corrosion resistivity of the HAP coating on the post-passivated PoPD-coated 316L SS was due to an effective barrier of PoPD followed by the passive film underneath the PoPD.  相似文献   

19.
Methacrylate based copolymers are considered as one of the best organic coating materials for anticorrosive application. Poly(N-vinyl carbazole-co-glycidyl methacrylate) have been synthesized by free radical solution polymerization technique from different mole ratios of N-vinyl carbazole (N-Vc) and glycidyl methacrylate (GMA) and characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR). Thermal analyses of the poly(N-Vc-co-GMA) were performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The number average molecular weight (Mn) of different compositions of the same was determined by gel permeation chromatography (GPC). The corrosion performances of low nickel stainless steel specimens coated with different composition of copolymers were investigated in 1 M H2SO4 using potentiodynamic polarization, electrochemical impedance spectroscopic (EIS) method, scanning electron microscopic (SEM) and energy dispersive X-ray analysis (EDAX). Poly(N-Vc-co-GMA) have been provided in order to achieve adherent, low permeability to aggressive ions as well as environmentally favored good anticorrosive coating. Electrochemical corrosion test and surface analysis results clearly showed that poly(N-Vc-co-GMA) coatings served as a stable host matrix on low nickel stainless steel against corrosion. It was also observed that the coatings of poly(N-Vc-co-GMA) with equal mole ratio of N-Vc and GMA exhibited the best corrosion resistance among all combinations.  相似文献   

20.
Objective of this study is to develop a highly effective and durable phosphorus based epoxy resin as anticorrosive coating material for carbon steel in 3% NaCl medium. The hexaglycidyl N,N′,N″-tris (4,4′-ethylene dianiline) phosphoramide (HGTEDPA) was characterized using spectral methods. The anticorrosive formulation (HGTEDPA-MDA) was synthesized using HGTEDPA curing with 4,4′-methylenedianiline (MDA). The formulation (HGTEDPA-MDA) coated steel specimens were exposed to UV radiation for a specific durable (189 days) and durability of the formulation was tested along with its inhibition effectiveness. The anticorrosive property of the formulation was evaluated using electrochemical (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP)) methods. Results showed that HGTEDPA-MDA coating improved the corrosion resistance value even after exposing 180 days to the UV radiation. PDP study suggested that HGTEDPA-MDA before and after UV radiations acted as mainly anodic and cathodic type of inhibitor, respectively. The EIS and PDP results were corroborated with density functional theory (DFT) and molecular dynamic simulations (MDS) methods and a reasonable good agreement was observed. DFT study revealed that HGTEDPA-MDA interacts with the metallic surface using donor–acceptor interactions. MDS study revealed that HGTEDPA-MDA spontaneously interacts with steel surface and adsorb using horizontal orientation.  相似文献   

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