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41.
N‐Oligo(3‐hydroxybutyrate)‐functionalized polypyrroles: towards bio‐erodible conducting copolymers
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Anna Domagala Wojciech Domagala Przemyslaw Ledwon Marta Musiol Henryk Janeczek Agnieszka Stolarczyk Piotr Kurcok Grazyna Adamus Mieczyslaw Lapkowski 《Polymer International》2016,65(12):1395-1404
New copolymer materials have been prepared by chemical grafting of oligomeric 3‐hydroxybutyric acid (OHB) onto polypyrrole (PPy) derivatives. The influence of grafting density and molecular weight of OHB brushes on the physicochemical properties of prepared copolymers was investigated. PPy substrates were prepared by FeCl3‐driven oxidative homopolymerization of N‐(2‐carboxyethyl)pyrrole or its copolymerization with pyrrole. The grafting method employed involved controlled anionic polymerization of β‐butyrolactone on pyrrole‐tethered potassium carboxylate active sites. Obtained PPy‐g‐OHB copolymers of varying grafting density and pendant polyester chain length were characterized and the observed structure–property relationships discussed. The impact of real time exposure to phosphate‐buffered saline environment was investigated and the residue products were characterized. Cross‐correlation of spectroscopic, thermal, electrical and elemental analysis data afforded comprehensive evaluation of the structure of prepared materials and their behaviour in hydrolytic medium. Erosion and degradation pathways have been identified, indicating ways to consciously tailor the physicochemical properties of these new biomimetic materials. © 2016 Society of Chemical Industry 相似文献
42.
Polypyrrole–thermoplastic composite films were obtained by casting. Homogeneous films were prepared with dispersant poly(vinyl methyl ether) or poly(vinyl ethyl ether) by two methods. Electric conductivity, morphology, mechanical properties, and sensitivity to H2O2 in water were studied. Composites of polypyrrole with poly(vinyl chloride) carboxylated and poly(vinyl methyl ether) presented improved mechanical and electrical properties compared with other composites studied. These films were sensitive to H2O2 in water, showing a significant change in electric resistance. This change is discussed in relation to the H2O2 concentration and the exposure time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1498–1506, 2001 相似文献
43.
《国际聚合物材料杂志》2012,61(8):424-429
A free-standing PPy/pTS film with a novel micro ring structured surface morphology have been electropolymerized by using CTAB/SDBS catanionic vesicles as templates. Characterizations showed that the micro ring structured PPy/pTS film was chemically similar to typical PPy/pTS films, while some DBS anions were also incorporated into the film from the mixed surfactants solutions. The micro ring structured PPy/pTS showed a slightly lower conductivity than conventional PPy/pTS films, due to the incorporation of DBS anions. The micro ring structured PPy/pTS films showed improved actuation stability compared to the conventional PPy/pTS films. 相似文献
44.
In the present investigation, Greigite-conducting polypyrrole nanocomposite (GPPy nanocomposite) was prepared, characterized and used to remove arsenite and arsenate from aqueous solution. Fe3S4 was synthesized using solvothermal synthetic method and it was grafted to conducting polypyrrole matrix. The nanocomposite was characterized using FE-SEM, EDX, XRD, FTIR, TGA/DSC and BET surface area. Kinetic studies revealed that the removal process followed first order kinetics. Batch isotherm studies were performed to determine the binding capacity. Thermodynamic parameters were also computed and it indicated the spontaneous nature of the process. Electrophoretic studies were carried out to determine the point of zero charge. 相似文献
45.
BACKGROUND: The solubility and conductivity of chemically synthesized polypyrrole (PPy) are dependent on the synthesis procedure and composition. Enhanced processability of PPy with high conductivity can be achieved using the anionic polyelectrolyte poly(styrene sulfonate) (PSS). RESULTS: High‐conductivity PPy with better processability was successfully synthesized by in situ chemical oxidation polymerization using various concentrations of PSS. Elemental analysis results show that the C/S and N/S molar ratios of the PPy fabricated in the presence of PSS are in good agreement with theoretical values for PPy–SO4. The S/N ratio increases with increasing PSS content, indicating the high doping level for PPy as the PSS content increases. Scanning electron microscopy and high‐resolution transmission electron microscopy images show that the fabricated PPy has spherical structures with the average particle size for the pure PPy being about 250 nm and markedly decreasing to 20–40 nm with the addition of PSS. CONCLUSION: The conductivities of PPy synthesized with a PSS/pyrrole monomer weight ratio of 0.25 are about five times higher than that of PPy matrix. These results are perhaps due to the part played by PSS serving as a dopant to be incorporated into the PPy structure to improve the conductivity of the fabricated PPy. Copyright © 2009 Society of Chemical Industry 相似文献
46.
L. Makhloufi H. Hammache B. Saidani N. Akilal Y. Maloum 《Journal of Applied Electrochemistry》2000,30(10):1143-1150
Conducting polypyrrole electrodes obtained under galvanostatic electropolymerization on iron from aqueous solutions of pyrrole and oxalic acid were modified with copper particles using the electrochemical cementation process. The electrochemical response of these modified electrodes was compared to that of the unmodified polymer electrode and also to that of bare metallic copper. The modified polypyrrole electrode showed noticeable enhancement for the rate of proton reduction. 相似文献
47.
The anodic codeposition of polypyrrole and TiO2 on AISI 1010 steel substrates in oxalic acid medium was studied from the standpoint of their use as protective coatings against corrosion. The influence of surface treatment, pH, stirring and current density (j) on the current efficiency () and pigment concentration incorporated in the polymer (C
c) were investigated. The highest C
c values (7.5%) were found at j = 5 mA cm–2, pH 4 and stirred baths. The composites were characterized by adherence and surface roughness tests, XPS, EDX, SEM, FTIR and cyclic voltammetry. 相似文献
48.
采用浸镀法在镁基体表面制备了Nafion/聚吡咯和Nafion/二甲基亚砜(DMSO)有机涂层,利用光学显微镜和电化学测量系统研究了有机涂层的形貌及其耐蚀性能.结果表明,Nafion/聚吡咯有机涂层的厚度随着浸镀次数的增加几乎不变,且Nafion/聚吡咯有机涂层降低了镁的耐蚀性能;而Nafion/DMSO有机涂层的厚度则随着浸镀次数的增加而线性增加,并且Nafion/DMSO有机涂层能有效地改善镁的耐蚀性能,耐蚀性能随着涂层厚度的增加而提高.与无涂层的试样相比,耐蚀性能最高提高18倍. 相似文献
49.
50.
The properties and electrocatalytic activity were studied of composite carbon‐supported materials based on heterocyclic polymer and nickel, in particular carbon/polyaniline/nickel, carbon/polypyrrole/nickel, carbon/poly(3‐methylthiophene)/nickel, as well as their precursors, carbon/polyaniline, carbon/polypyrrole, and carbon/poly(3‐methylthiophene). The materials were characterized by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), EDAX, and electrochemical methods, such as cyclic voltammetry and linear voltammetry using RDE. SEM show porous materials, with a particle size of around 0.3 μm. It was found that in nickel‐modified catalysts between 5 and 6 wt % of nickel is obtained. TGA and FTIR show that the modification with nickel alters the polymer bonds. Curves from cyclic voltammetry show cathodic peaks corresponding to the oxygen reduction reaction (ORR) in all materials, occurring at relatively low potentials. Based on the potential range for ORR as well as kinetic parameters obtained from linear voltammetry using RDE, it was concluded that C‐Ppy‐Ni shows the best performance for ORR in acidic medium. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献