Synthesis and characterization of polypyrrole/TiO2 composites on mild steel

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.     

Synthesis and characterization of secondary doped polypyrrole/organic modified attapulgite conductive composites

Secondary doping method was introduced into fabricating polypyrrole/oganic modified attapulgite conductive composites. The preparation conditions, such as amount of hexadecylpyridinium chloride (CPC, modifying agent), organic modified attapulgite (OATP), and HCl (secondary dopant) have been optimized to get the composites with the highest conductivity. When m_CPC/m_ATP, m_OATP/m_Py, and n_HCl/n_SA (SA is sulfamic acid) reaches 0.03, 0.6, and 0.5, respectively, the PPy/OATP composites possess the highest conductivity of 87.59 S cm^?1 as well as the highest thermal degradation temperature of 249.29°C. Scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, UV‐Visible diffuse reflectance study, and X‐ray photoelectron Spectroscopy results showed that PPy chains form the core‐shell structure and may combine with OATP via π–π stacking interaction. Thermogravimetric analysis showed that the thermal stability of PPy/OATP‐SH composites was enhanced and these could be attributed to the retardation effect of OATP as barriers for the degradation of PPy. This method may open a new door for PPy‐based composites with special structures, higher performance, and thus broader application ranges. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41407.     

Preparation and characterization of polypyrrole/selenium composites

This article reports synthesis of polypyrrole (PPy) and its composites having various amounts of selenium (Se) in the presence of nitric acid in aqueous medium via chemical oxidative polymerization. Samples were spectroscopically characterized using Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, and atomic absorption spectroscopy. Although morphology of the samples was examined by using scanning electron microscopy (SEM), their thermal properties were studied via differential scanning calorimetry (DSC). The alternating current (ac) conductivity and dielectric properties were investigated as a function of temperature. Variation of adsorption free energy obtained from Langmuir adsorption isotherm showed that metal cations were physically adsorbed onto the polymer surface. SEM images showed that filling process significantly changes the morphology of PPy. DSC results indicated that cold crystallization temperature (T_cc) of unfilled PPy decreases with increasing filling level. Dielectric measurements showed that relaxation times for PPy and its composites have decreased linearly with increasing temperature. The conductivity of the PPy, when filled with 1 g of Se, increased ～ four times at room temperature for 1 kHz. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Novel Ni/polypyrrole and Cu/polypyrrole composites prepared in the presence of different acids: Synthesis and investigation of thermal stability

We report the synthesis and characterization of new organic/inorganic hybrid materials constituted of Ni(0) and Cu(0) nanoparticles and polypyrrole (PPy). Copper and nickel nanoclusters were synthesized by a chemical reduction of aqueous metal salt solutions by sodium borohydride. PPy/Ni(0) and PPy/Cu(0) composites were obtained in the presence of two different acids (H₃BO₃, CH₃COOH), by polymerizing pyrrole‐Ni and pyrrole‐Cu particles by using iron (III) chloride. The composites have been characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and magnetic susceptibility techniques. Conductivity measurements of samples were taken using four‐probe devices. The PPy/Ni(0) and PPy/Cu(0) nanocomposites doped with different acids exhibited higher conductivity values than those of homopolymers. Among all samples, Ni/PPy‐H₃BO₃ has the highest conductivity (1.42 S cm^?1). Homopolymers and composites showed a stable and increasing conductivity with increasing temperature, except Ni(0). We observed that from TGA analysis of polymers, metal composites of PPy synthesized in two different media are more stable than those of PPy‐CH₃COOH and PPy‐H₃BO₃. The magnetic susceptibility values of homopolymers and Cu are negative, whereas the other samples are positive. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and structural investigation of conductive composites from cellophane and polypyrrole

A versatile method for preparing conducting composites from cellophane and pyrrole by an interface technique has been attempted. Polymerization of pyrrole into the porous matrix of cellophane produces black, flexible composite film with conductivity comparable to that of polypyrrole and mechanical properties very similar to cellophane. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of polypyrrole composites for corrosion protection of steel

Corrosion protection performance of epoxy polyamide coatings containing polypyrrole (PPy) composites for steel has been studied. PPy and its composites have been synthesized chemically using potassium permanganate and potassium per sulfate as oxidants. The PPy has been characterized by four probe method for conductivity, atomic absorption spectroscopy for elemental analysis, and Fourier transform infrared spectra for proving the incorporation of dopant in this polymers. The X‐ray diffraction (XRD) study has revealed the presence of manganese dioxide in the polymer. The elemental analysis and the thermo gravimetric analysis measurements showed that the presence of manganese dioxide in the polymer is about 75%. The thermal stability of deprotonated polymer has improved. Electrochemical impedance spectroscopic analysis indicated that the epoxy polyamide/PPy‐MnO₂ coating showed the maximum resistance value of 2.196 × 10⁷ Ω cm² after 30 days immersion in 3% sodium chloride solution. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of graphite oxide/polypyrrole composites

Graphite oxide (GO)/polypyrrole (PPy) composites (GPs) and 1,5-naphthalene disulfonic acid (1,5-NDA) doped GPs (1,5-NGPs) have been successfully synthesized via in situ polymerization of pyrrole on GO. The conductivity of 1,5-NGPs is as high as 7 S/cm, seven orders of magnitude higher than that of pristine GO. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show PPy “dressed” on the surface of GO layers, while Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirm the interaction between GO and PPy. The results of thermogravimetric analysis (TGA) and heat treatment at 1000 °C show that the “dressed” PPy on the surface of GO layers in GPs and 1,5-NGPs has effectively prevented the deflagration of GO.     

Anodic formation of polypyrrole/tungsten trioxide composites

The anodic codeposition of WO₃ and polypyrrole at constant current densities was studied. The powdery solid was dispersed in the electrolyte (0.1m pyrrole, 0.1m LiClO₄) under strong convection at c _L = 0.01–30 g dm⁻³. Water or wet acetonitrile were employed as solvents. Various modes of convection were developed. The resulting WO₃ Concentrations in the PPy/WO₃ composites were up to c _C = 53 wt%. c _C was found to increase with increasing convection intensity and with decreasing current density. Quantitative evaluation leads to a relationship c _C = K log c _E/c _E.0, where K is a constant,and c _E.0 is a threshold concentration. This equation was derived from a model assuming a Temkin type adsorption of the impinging particles and their field enhanced final incorporation into the polypyrrole matrix K is proportional to j ⁻¹. The new model complements the older theory of Guglielmi originally developed for systems with metal matrices, and it also holds for these very well known composites. The homogeneous distribution of WO₃ in PPy is demonstrated by the linear increase of the WO₃ mass with the thickness of the composite in combination with SEM techniques.     

Fabrication and characterization of multilayer SiO2/polymethacrylic acid/polypyrrole composites and hollow polypyrrole microspheres

Methacrylic acid was polymerized on the 3‐(methacryloxy)propyl trimethoxysilane‐modified silica core. The carboxylic acid groups of polymethacrylic acid (PMAA) not only provide the “active‐sites” for growth of the pyrrole monomers but also act as doping acids for polypyrrole (PPy). By in situ polymerization route, SiO₂/PMAA/PPy multilayer composites and hollow PPy microspheres with controllable shell thickness were fabricated. The morphologies, sizes, and structures of the nanocomposites were investigated in detail by transmission electron microscopy, scanning electron microscopy, Fourier‐transform infrared spectra, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚吡咯/二氧化锰复合材料的制备及其电化学性能研究

利用水热法合成了海胆状MnO_2,通过吡咯聚合制备了PPy@MnO_2复合结构,研究了包覆时间、包覆量对PPy@MnO_2电化学性能的影响。用PPy@MnO_2纳米复合材料作为工作电极,在1 mol/L的Na_2SO_4溶液中利用三电极体系进行了电化学性能测试。PPy@MnO_2纳米复合材料的循环伏安、恒电流充放电和电化学阻抗谱(EIS)研究表明,PPy@α-MnO_2-60纳米复合材料在吡咯与二氧化锰质量比10∶1、包覆时间6 h时电化学性能最佳,在电流密度0.5 A/g时比电容值为177.3 F/g。     

聚吡咯/氧化石墨烯复合材料的制备及电化学性能研究

分别采用物理球磨混合法、化学原位聚合法和化学原位聚合-还原法制备了聚吡咯/氧化石墨烯混合物、聚吡咯/氧化石墨烯(PPy/GO)和聚吡咯/还原氧化石墨烯(PPy/RGO)复合材料。通过三电极测试其电化学性能(循环伏安、恒流充放电和交流阻抗)。结果表明,通过化学原位聚合法制备的PPy/GO(304. 5 F/g)比电容远高于物理混合(16 F/g)和聚吡咯/还原氧化石墨烯(126. 4 F/g)。化学法原位聚合法制备PPy/GO最佳条件是冰浴条件下和加入表面活性剂对羟基苯磺酸钠。并通过X射线衍射(XRD)和扫描电子显微镜(SEM)对化学原位制备的PPy/GO组成、结构和形貌进行了表征。     

一步水热法合成铜改性的介孔γ-Al_2O_3及其吸附脱硫性能研究

采用一步水热合成法,以Al(NO3)3为铝源,P123为模板剂,Na OH、Na2CO3和K2CO3分别为沉淀剂,Cu(NO3)2为铜源,制备出负载铜的金属有序介孔γ-Al2O3,并运用N2吸附-脱附和XRD等技术对其结构进行表征,同时探讨了铜改性的介孔γ-Al2O3对模型燃油中的噻吩的吸附性能。结果表明,这3种沉淀剂都能制备出比表面积大(>226 m2/g),孔径分布中心为3.3 nm,孔体积为0.27⁰.35 cm3/g的负载铜的介孔γ-Al2O3,且样品都保持了较好的介孔结构。样品对模型燃油中噻吩的吸附脱硫性能表明,用Na OH作为沉淀剂且负载铜的介孔γ-Al2O3样品对噻吩的吸附性能较好,原因在于此样品具有较大的比表面积且铜在此样品中的分散性较好。     

Characterization of anodically formed polypyrrole/tungsten trioxide composites

Composite PPy/WO₃ materials were synthesized anodically under various conditions. The cyclovoltammetric switching curves are very close to the blank polypyrrole. The redox behaviour of the filler is only detected through electrochromism, leading to a yellow grey colour at +0.4 V vs SCE and to a green surface at –0.6 V. For overoxidation of the composite, a degree of overoxidation Y = 5 is found, the same as for the matrix alone. Photoelectrochemical response is due to the conducting polymer at negative potentials and even at 0 V vs SCE. A strong effect at positive potentials is due to the WO₃ pigment. From this, a flat band potential of +0.15 V vs SCE is determined for aqueous 0.1 m LiClO₄. Some non-electrochemical properties are also reported. Surface roughness increases with increasing WO₃ concentration, but for thicker layers, from MeCN, it decreases. SEM micrographs reveal homogeneous distribution of WO₃. Large secondary particles are observed in NBu₄BF₄ electrolyte. True and nominal thicknesses differ by up to a factor 1.65 due to the porous structure and this explains differences between densities measured by the flotation and the jump method. X-ray diffraction analysis exhibits unchanged WO₃-lines, but no PPy-lines due to the amorphous character. The conductivity of the composite from MeCN is much lower than expected by the volume filling of the WO₃.     

Synthesis and characterization of water‐soluble polypyrrole/multi‐walled carbon nanotube composites

Water‐soluble polypyrrole (PPy)/multi‐walled carbon nanotube (MWCNT) composites were prepared by mixing chemically modified MWCNTs carrying carboxylic groups (c‐MWCNTs) and sulfonated PPy (SPPy) aqueous colloids in solution. Fourier transform infrared spectroscopy, Raman spectroscopy, X‐ray photoelectron spectroscopy, X‐ray diffraction, field‐emission scanning electron microscopy and high‐resolution transmission electron microscopy were used to characterize the structure and morphology of the resulting composites. Raman and X‐ray photoelectron spectra demonstrate the presence of electrostatic interactions between the radical species of the SPPy and the carboxylic acid species of the c‐MWCNTs. The addition of c‐MWCNTs into SPPy efficiently enhances its thermal stability and electrical conductivity. Owing to the doping effect and one‐dimensional linear structure of the c‐MWCNTs, the conductivity of SPPy/c‐MWCNT composites at room temperature is increased by two orders of magnitude by the introduction of 5 wt% c‐MWCNTs into the SPPy matrix. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of montmorillonite/polypyrrole nanocomposite

A novel montmorillonite (MMT)/polypyrrole (PPy) nanocomposite (MPN) with high electrical conductivity and thermal stability has been synthesized via in‐situ polymerization. The surface morphology, characterization, thermal stability, and electrical conductivity have been tested by scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and four‐probe methods, respectively. SEM results show that the antenna‐like PPy deposits on the layer surface of MMT. FTIR and XRD analyses show that there is interaction between MMT and PPy. The nanocomposite has high electrical conductivity (4 S/cm), eight orders of magnitude higher than that of pristine MMT. The thermal stability of MPN is higher than the pure PPy as well as the mixture of MMT and PPy (MMP). POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Electrochemical inspection of polypyrrole/chitosan/zinc oxide hybrid composites

Polymer nanocomposite composed of polypyrrole, chitosan, and zinc oxide nanoparticles has been synthesized and it has been evaluated for various electrochemical aspects of the current electrochemical industry. The polypyrrole (PPy) was synthesized by the chemical oxidative polymerization reaction by employing ammonium persulfate as oxidizing agent. Composites of polypyrrole/chitosan (PPy/Chy) and polypyrrole/chitosan/ZnO (PCZ) composites were synthesized by the solution blending method. Detailed structural, morphological, thermal characterization of PPy, PPy/Chy, and PCZ were performed to characterize the specific features of the systems. The composites exhibit better thermal stability and high surface area and the addition of ZnO nanoparticle increase the crystallinity of the composite. Electrochemical characterization of the ITO electrodes modified with PPy, PPy/Chy, and PCZ were performed using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry techniques. The present study highlights the role of a bio-compatible material with high surface area and conductive constituent for designing of various high performing electronic noninvasive sensors, biosensors, and so forth.     

Synthesis and interfacial properties of montmorillonite/polypyrrole nanocomposites

Montmorillonite/polypyrrole (MMT/PPy) nanocomposites were prepared by the in situ polymerization of pyrrole in the presence of MMT. The morphology of the MMT/PPy nanocomposites as examined by scanning electron microscopy differs slightly from that of the untreated MMT but markedly from that of polypyrrole. X-ray photoelectron spectroscopy (XPS) showed that the materials have MMT-rich surfaces, an indication that polypyrrole is essentially intercalated in the host clay galleries. The transmission electron microscopy showed, that the interlamellar spacing of the untreated MMT increased from 1.25 to 18.9 nm, when compared to nanocomposite MMT/10.8% PPy. Moreover, XPS highlighted the cation exchange of Na⁺ from montmorillonite by K⁺ (from the oxidant) and by the positively charged polypyrrole chains. Inverse gas chromatography indicated that the nanocomposites are high surface energy materials with a dispersive contribution to the surface energy reaching 200 mJ/m² at 150 °C, for a PPy loading of 21.4 wt%. The values of the MMT/PPy nanocomposites were correlated to the changes in the specific surface area of the MMT induced by the intercalation of polypyrrole.     

Synthesis and properties of magnetite/polypyrrole core–shell nanocomposites and polypyrrole hollow spheres

In this work a new route for preparation of core–shell nanoparticles composed of an iron oxide core and a polypyrrole (PPy) shell is explored. During the preparation procedure the initially formed iron(0) core is converted to magnetite. It is demonstrated, that the magnetite cores can completely be dissolved by reaction with acid. Furthermore the dissolution of iron oxide cores by electrolysis also is possible. The resulting PPy hollow spheres as well as the core–shell nanocomposites are electrochemically active.     

Preparation and characterization of composites of polypyrrole

In this paper, we report the preparation and characterization of composites of polypyrrole (PPy) with polyvinylidene fluoride (PVDF), and cellulose. We used the techniques of chemical and electrochemical polymerization. These materials were characterized using X-ray diffraction (wide and small angle (SAXS)), electrical conductivity and electron microscopy. The studies showed that homogeneous composites could be formed. The percentage crystallinity of the host polymer decreased, whereas some crystallization of PPy was noticed. SAXS studies revealed that the diffusion of PPy is in amorphous regions. The electrical conductivity of the composites was found to vary in the range of 10^?8 S/cm to 10^?4 S/cm. These composites were found to be useful in gas sensors for detection of chlorine and ammonia.     

Electrochemically synthesized graphene/polypyrrole composites and their use in supercapacitor

Composite films consisting of polypyrrole (PPy) and graphene oxide (GO) were electrochemically synthesized by electrooxidation of 0.1 M pyrrole in aqueous solution containing appropriate amounts of GO. Simultaneous chronoamperometric growth profiles and frequency changes on a quartz crystal microbalance showed that the anionic GO was incorporated in the growing GO/PPy composite to maintain its electrical neutrality. Subsequently, the GO was reduced electrochemically to form a reduced GO/PPy (RGO/PPy) composite by cyclic voltammetry. Specific capacitances estimated from galvanostatic discharge curves in 1 M H₂SO₄ at a current density of 1 A g^?1 indicated that values for the RGO/PPy composite were larger than those of a pristine PPy film and the GO/PPy composite. In the case of 6 mg mL^?1 GO for the preparation of GO/PPy, a high specific capacitance of 424 F g^?1 obtained at the electrochemically prepared RGO/PPy composite indicated its potential for use as an electrode material for supercapacitors.