Synthesis,characterizations, and physical properties of carbon nanotubes coated by conducting polypyrrole

A new type of carbon nanotube (CNT) (diameter of <100 nm) coated by conducting polypyrrole (PPY) was synthesized by in situ polymerization on CNTs. The structure of the resulting complex nanotubes (CNT‐PPY) was characterized by elemental analysis, X‐ray photoelectron spectroscopy, Raman spectra, and X‐ray diffraction. These indicated no significant chemical interaction between PPY and the CNT. The electrical, magnetic, and thermal properties of the complex nanotubes were measured and showed the physical properties of the CNTs were modified by conducting PPY. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2605–2610, 1999     

Characterization and physical properties investigation of conducting polypyrrole/TiO2 nanocomposites prepared through a one‐step “in situ” polymerization method

Nowadays, nanocomposites are a special class of materials having unique physical properties and wide application potential in diverse areas. The present research work describes an efficient method for synthesis of a series of polypyrrole/titanium dioxide (PPy/TiO₂) nanocomposites with different TiO₂ ratios. These nanocomposites were prepared by one‐step in situ deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl₃) as an oxidant in the presence of ultra fine grade powder of anatase TiO₂ nanoparticles cooled in an ice bath. The obtained nanocomposites were characterized by Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The obtained results showed that TiO₂ nanoparticles have been encapsulated by PPy with a strong effect on the morphology of PPy/TiO₂ nanocomposites. Also, the synthesized PPy/TiO₂ nanocomposites had higher thermal stability than that of pure PPy. The investigation of electrical conductivity of nanocomposites by four‐point probe instrument showed that the conductivity of nanocomposite at low TiO₂ content is much higher than of neat PPy, while with the increasing contents of TiO₂, the conductivity decreases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚吡咯/纳米氧化钇复合材料的结构与性能研究

用在位分散聚合法制得具有核壳结构的聚吡咯/纳米氧化钇复合材料,红外光谱和拉曼散射分析表明纳米氧化钇与聚吡咯之间存在化学作用,红外光谱有明显的蓝移现象,它们的反应发生在氮原子上。而随着Y2O3的加入,电导率呈下降的趋势。     

负载羧基化球状介孔纳米颗粒TFN膜的研究

在薄层复合膜(thin-film composite membrane, TFC膜)中引入无机纳米颗粒,形成薄层纳米复合膜(thin-film nanocomposite membrane, TFN膜),近几年作为反渗透膜开始应用于水处理研究。但是无机纳米颗粒在TFC膜中的性能的不稳定性和膜的机械强度等变成了突出问题。合成制备了粒径约为110 nm修饰羧基的介孔氧化硅球状纳米颗粒(MSN—COOH),并将其成功地化学键合在TFC膜的表面功能层交联网络中。与TFC膜相比,键合有MSN—COOH的TFN膜,水通量提高了56.2%,保持高脱盐率;由于单分散介孔纳米颗粒表面亲水官能团的引入,使膜表面的亲水性有很大程度提高,单分散介孔纳米颗粒在基体中的有序排列,使膜表面粗糙度降低,提高了膜的抗污染能力。与普通TFN膜相比较,具有更好的稳定性和柔韧性,可以在长时间高压过滤操作下保持稳定。     

Conducting polymer blends of polypyrrole with polyvinyl acetate,polystyrene, and polyvinyl chloride based toxic gas sensors

Blends of the conducting polymer, polypyrrole (PPy), and in the insulating host polymers, polyvinyl acetate (PVAc), polystyrene (PS), and polyvinyl chloride (PVC) resin, have been prepared chemically. Threshold conductivities occur at about 5% for PPy in blends with host polymers. The characterizations of these blends were done by FTIR, UV‐visible, differential scanning calorimetric (DSC), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The products of the blends have electrical conductivity comparable to PPy and mechanical properties similar to hosting polymers. The response mechanism of the conducting blends to a selection of gases and vapors was investigated using two techniques, measurement of conductance and mass changes using a four‐point probe method, and a X‐ray fluorescence (XRF) device, respectively. These responses of blends to toxic gases and vapors are more well explained. Prepared films were exposed to hydrogen halides (HCl, HBr, and HI), hydrogen cyanide, halogens (Cl₂, Br₂, and I₂), monochloroacetic acid (MCAA), 1‐3‐5 trichloromethyl benzene (TCMB), methylbenzyl bromide (MBB), bromoacetone (BA), and cyanogen bromide (CB). The changes of conductivity of polymers frequently observed are partly due to one stage in the two‐stage sorption, perhaps involving the swelling of the polymer, then diffusion gases into polymer chains. The swelling of polymers is a slow process, therefore, preswelled polymer films tend to decrease the response times of blends with respect to gases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 49–62, 2003     

Shrinking rate of conducting grains in HCl–protonated polyaniline,polypyrrole, and polypyrrole/polyaniline blends with their thermal aging

The dc electrical conductivity (σ) of HCl‐protonated polyaniline, polypyrrole, and their blends was measured from 80 to 300 K for thermal aging times between approximately 0 and 600 h. The thermal aging took place at 70°C under room atmosphere. The change of σ with the temperature (T) and the decrease of σ with the thermal aging time (t) are consistent with a granular metal type structure, in which conductive grains are randomly distributed into an insulating matrix. Aging makes the grains shrink in a corrosion‐like process. From σ = σ(T) measurements the ratio s/d, where s is the average separation between the grains and d their diameter, as well as the rate d(s/d)/dt of their decrease with t were calculated. These revealed that the conductive grains consist of a shell, in which aging proceeds at a decreasing rate, and a central core, which is consumed at a much slower rate. Our measurements not only permitted the estimation of the shell thickness, which lies between 0 and 5 Å, but also gave quantitative information about the quality of the shells and the cores from their aging rates. The shells are consumed with an average rate of d(s/d)/dt = 6.6 × 10^?4 (h^?1), which is about 5 times greater than the more durable cores. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 117–122, 2005     

Preparation and investigation of structural,magnetic, and microwave absorption properties of aluminum‐doped strontium ferrite/MWCNT/polyaniline nanocomposite at KU‐band frequency

Aluminum‐doped strontium hexaferrite nanoparticle SrAl_1.3Fe_10.7O₁₉ was prepared by sol–gel method and polyaniline (PANi) multiphase magnetic nanocomposite SrAl_1.3Fe_10.7O₁₉/MWCNT/PANi was synthesized through a sonochemical method by in situ polymerization. The morphology, structure, and magnetic properties of the nanocomposites are investigated by field emission scanning electron microscopy, X‐ray powder diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. The electromagnetic interference shielding efficiency was evaluated in the KU‐band (12.4–18 GHz). The reflection loss (RL) value showed that the composites have an excellent absorbing property in the KU‐band, minimum ?24.93 dB at 16.40 GHz with a bandwidth of 2.81 GHz (shielding effectiveness up to 10 dB) at a matching thickness 6.5 mm. The RL value of the SrAl_1.3Fe_10.7O₁₉/MWCNT nanocomposite was ?15.92 dB at 15.84 GHz with a bandwidth of 1.66 GHz (with a shielding effectiveness up to 10 dB). These results disclose the remarkable microwave shielding ability of SrAl_1.3Fe_10.7O₁₉/MWCNT/PANi in KU‐band due to the interactive effect of the three components. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45135.     

Role of amphiphilic dopants on the shape and properties of electrically conducting polyaniline‐clay nanocomposite

The role of functionality and rigidity of the amphiphilic dopants on the morphology and electrical property of the polyaniline‐clay nanocomposites (PANICNs) were studied by preparing polyaniline (PANI) and PANICNs using five structurally different amphiphilic dopants having backbone—phenyl, naphthyl, alicyclic, and alkyl groups. Effect of the size and functionality of the dopant on the extent of intercalation/exfoliation, morphology, thermal stability, and phase transitions were studied. PANICNs exhibited different morphologies such as nano/micro granules, rods, nanotubes, aggregated layers/clusters, and rice grain for PANICN‐2,6‐naphthalene sulphonic acid, PANICN‐para‐toluene sulphonic acid, PANICN‐stearic acid, PANICN‐dodecyl benzene sulphonic acid, and PANICN‐camphor sulphonic acid, respectively. X‐ray diffraction, Fourier transform infrared, and scanning electron microscopic studies showed that the self‐assembled nano/microstured aggregates were formed by the combined effect of many noncovalent interactions such as phenyl–phenyl stacking, hydrogen bonding, ion–dipole interaction, π–π stacking, and electrostatic layer‐by‐layer self‐assembling. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009.     

Mechanical properties of conducting H‐type polysiloxane–polypyrrole graft copolymers and polytetrahydrofuran–polypyrrole block copolymers

The mechanical properties of block copolymers of polypyrrole and pyrrolyl‐ended azobis‐polytetrahydrofuran (TPPy) and graft copolymers of pyrrolyl‐ended H‐type polydimethylsiloxane (SPPy) were investigated and compared with those of polypyrrole (PPy). Conducting films were prepared electrochemically at a constant potential and doped with p‐toluene sulfonate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1663–1666, 2002     

Preparation and characterization of fluorescent polymer magnetic particles

Magnetic iron oxide (maghemite, Fe₃O₄) particles were encapsulated with fluorescent polymer phase. The resulting fluorescent magnetic polymer particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimeter analysis (TGA), reflection optical microscopy, differential scanning calorimeter (DSC), Fritsch particle sizer, scanning electron microscopy (SEM), powder X‐ray diffractometer (XRD), and vibrating sample magnetometer (VSM) measurements. FTIR and XRD confirmed the presence of iron oxide in polymer phase. The TGA and DSC measurements indicated that the magnetic polymer particles have more than 50% iron oxide content and high thermal stability. SEM and reflection optical microscopy under UV light revealed that all maghemite particles were embedded in the polymer spheres and have fluorescent characteristics. The size‐distribution analysis of prepared magnetic particles was shown that the means diameter of the particles slightly increased. According to our magnetometry data, shape of the loops evidences the ferromagnetic character of the material and no evidence of superparamagnetism was seen. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation,characterization, and dynamic adsorption–desorption studies on polypyrrole encapsulated TiO2 nanoparticles

Binary doped polypyrrole (PPy) encapsulated Titania (TiO₂) nanoparticles were prepared by oxidative polymerization using FeCl₃ as oxidant in presence of camphorsulfonic acid (CSA) as surfactant. Both FeCl₃ (oxidant) and camphorsulfonic acid (surfactant) also act as dopant and hence thus prepared polypyrrole/Titania (TiO₂@PPy) is termed as binary doped nanocomposite i.e. FeCl₃ dopes polypyrrole by oxidation mechanism while camphorsulfonic acid dopes polypyrrole by protonic doping mechanism. The TiO₂@PPy coreshell nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetry, differential scanning calorimetry (DSC), field emission‐scanning electron microscopy (FE‐SEM), and inductance‐capacitance‐resistance (LCR) measurements. The results indicated that the structural and electrical properties of the TiO₂@PPy coreshell nanocomposites were significantly influenced by the extent of TiO₂ nanoparticles loading of polypyrrole. The direct current (DC) electrical conductivity of the as‐prepared TiO₂@PPy coreshell nanocomposites was higher than that of PPy. As‐prepared TiO₂@PPy coreshell nanocomposites were also studied for their dielectric losses for alternating current (AC) which is useful characteristic for their application in the fabrication of charge storing devices. TiO₂@PPy coreshell nanocomposites showed synergistic effect of combining components in improving their alcohol sensing properties. This improvement may be attributed to the adsorption on and desorption from alcohols TiO₂@PPy interface of the nanocomposites and alcohol vapors causing decrease in depletion region. The TiO₂@PPy coreshell nanocomposites were observed to show better reproducibility of electrical conductivity and fast self‐recovery during the alcohol vapor sensing process. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43411.     

Physical and tensile properties of epoxy laminated magnetic bacterial cellulose nanocomposite films

Despite many potential applications, the adverse impacts of magnetic nanoparticles on the tensile properties of magnetic cellulose papers and films are well established. On the other hand, water absorption and thickness swelling of cellulose materials are important limiting factors in many engineering applications. These challenges caused limited applications of magnetic cellulose nanocomposites. The aim of this study is to examine the possibility of modifying the physical and mechanical behaviors of magnetic bacterial cellulose films by epoxy resin lamination. Results showed that the tensile modulus and strength of the magnetic bacterial cellulose film, respectively, increased about 280% and 240% after epoxy lamination while they maintained their desirable magnetic and flexibility properties. Furthermore, the water absorption and thickness swelling of the epoxy laminated magnetic nanocomposite films, respectively, improved about 43% and 42%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45118.     

Preparation of polyaniline/nickel oxide nanocomposites by liquid/liquid interfacial polymerization and evaluation of their electrical,electrochemical and magnetic properties

A novel route has been developed to synthesize polyaniline (PANI)/nickel oxide (NiO) nanocomposites via liquid/liquid interfacial polymerization where NiO and the initiator were dispersed in the aqueous phase and the monomer was dissolved in the organic phase. The synthesized samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet?visible absorption, X‐ray diffraction, and electrochemical, electrical conductivity and magnetic property measurements. NiO was dispersed uniformly within the PANI matrix. The composites exhibited noticeable improvement in thermal stability and electrical conductivity in comparison with pure PANI. The composites showed excellent electrochemical reversibility at a scan rate of 0.1 V s^?1 and good redox stability even up to 100 cycles. The room temperature magnetic hysteresis measurements show a low value of coercivity for the polymer composites in comparison with NiO. The remnant magnetization (M_r) values were found to be increased with increasing concentration of NiO in the composites. © 2013 Society of Chemical Industry     

Magnetic and conducting Fe3O4–polypyrrole nanoparticles with core‐shell structure

Magnetic and conducting Fe₃O₄–polypyrrole nanoparticles with core‐shell structure were prepared in the presence of Fe₃O₄ magnetic fluid in aqueous solution containing sodium dodecylbenzenesulfonate (NaDS) as a surfactant and dopant. Both the conductivity and magnetization of the composites depend strongly on the Fe₃O₄ content and the doping degree. With increase of Fe₃O₄ content in the composite, the conductivity at room temperature decreases, but the saturated magnetization and coercive force increase. Transmission electron microscopy (TEM) images of Fe₃O₄ and Fe₃O₄–polypyrrole particles show almost spherical particles with diameters ranging from 20 to 30 and 30 to 40 nm, respectively. The thermal stability of Fe₃O₄–polypyrrole composites is higher than that of pure polypyrrole. Studies of IR, UV–visible and X‐ray photoelectron spectroscopy (XPS) spectra suggest that the increased thermal stability may be due to interactions between Fe₃O₄ particles and polypyrrole backbone. Copyright © 2003 Society of Chemical Industry     

Synthesis and characterization of a ferrocene‐modified,polyaniline‐like conducting polymer

A novel monomer called 1,1′‐ferrocenediacyl anilide (FcA) was synthesized from ferrocene (Fc). Copolymerization was carried out between FcA and aniline (ANI) by an electrochemical method. The novel monomer and copolymer were characterized with ¹H‐NMR, Fourier transform infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–vis) spectroscopy. The hydrogen protons of the benzene ring were moved to a low field in ¹H‐NMR, and the absorption band of N?Q?N (where Q is the quinoid ring) appeared in the FTIR spectrum of the polymer. The peaks of both Fc and the π–π* electronic transition in the UV–vis spectra were redshifted. The results indicate that the copolymer mainly existed as a highly delocalized conjugated system. X‐ray diffraction analysis established further proof, and the process of electrochemical deposition was observed by scanning electron microscopy. The optimal synthesis conditions of the copolymer were determined through changes in the monomer molar ratios and the scan rate. The ideal performance of the copolymer was gained when the monomer molar ratio between FcA and ANI was 1:4 and the scan rate was 50 mV/s. Furthermore, the electrochemical performances were tested in detail by cyclic voltammetry, galvanostatic charge–discharge testing, and electrochemical impedance spectroscopy. The results show that the specific capacitance of poly(1,1′‐ferrocenediacyl anilide‐co‐aniline) increased up to 433.1 F/g at 0.5 A/g, the diffusion resistance was very small, and the durability was good enough. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43217.     

Structural,electrical, and electromagnetic properties of cotton fabrics coated with polyaniline and polypyrrole

In this study, the structural, electrical, and electromagnetic properties of cotton fabrics coated with polyaniline (PAni) and polypyrrole (PPy) were investigated and compared. For the aims, anilin and pyrrole were used as monomers, and in situ polymerization on cotton fabric by chemical oxidative polymerization was performed. After production, the structural properties of the fabrics were determined with Fourier transform infrared spectroscopy and X‐ray diffraction. In addition, ultraviolet (UV) permeability, tensile strength, colorfastness, and electrical and electromagnetic measurements of the fabric samples were carried out. The resistance values of the cotton fabrics coated with PAni and PPy were found to be 350 and 512 Ω, respectively. The average electromagnetic shielding efficiency and average absorption values of the cotton fabrics coated with PAni were determined to be 3.8 dB and 48%, respectively, and these values for the cotton fabrics coated with PPy were 6 dB and 50%, respectively. Consequently, a significant difference was not observed between the resistance values and electromagnetic parameters of the fabrics coated with PAni and PPy, although the intact textile characteristics of the fabric coated with PPy were protected and improved, whereas the characteristics of the fabric coated with PAni were inferior. Moreover, we first report that the fabrics coated with conductive polymers had excellent UV‐protection properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A study on the effect of the collector properties on the fabrication of magnetic polystyrene nanocomposite fibers using the electrospinning technique

The role of the collector properties in changing the fiber morphology in electrospinning has not been completely understood yet. In this work, we studied the effect of different collectors on the helicity of the magnetic polystyrene nanocomposite fibers containing superparamagnetic magnetite nanoparticles. Aluminum and ice were used as solid collectors. Ethanol, ethanol-deionized (DI) water mixture, sodium dodecyl sulfate, Triton X-100, deionized water, and NaCl baths were used as liquid collectors. Ice, when surrounded by a conductive foil, produced excellent fiber alignment, but increased local humidity, inhibiting the continuous jet formation. The deionized water and NaCl bath exhibited minimum helicity. The surfactant bath produced different structures such as coiled, helical, and zig-zag with varied diameters. Ethanol and DI/Ethanol baths were found to retain the structure of the deformed fiber formed due to jet instability. The helicity of the fibers was observed to increase with decreasing surface tension. Incorporation of the magnetic phase affected the viscosity of the polymer solution and the hydrophobicity of the polystyrene fibers further influencing the obtained morphologies.     

Synthesis and electrochemical properties of graphene oxide/nanosulfur/polypyrrole ternary nanocomposite hydrogel for supercapacitors

A method for synthesizing Graphene oxide (GO)/nano‐sulfur/polypyrrole (PPy) ternary nanocomposite hydrogel is depicted. The higher surface area of GO, PPy porous structure and their excellent conductivity are utilized, and the GO hydrogel can be made easily. The products are characterized by field‐emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, and electrochemical workstation. The results demonstrated that GO/nano‐S/PPy ternary nanocomposite hydrogel is successfully synthesized. The electrochemical properties are investigated by cyclic voltammetry, galvanostatic charge/discharge measurements, and cycling life in a three‐electrode system in 1M Li₂SO₄ electrolyte solution. The GO/nano‐S/PPy ternary nanocomposite hydrogel exhibit a high specific capacitance of 892.5 F g^?1 at scan rates of 5 mV s^?1 and the capacitance retain about 81.2% (594.8 F g^?1) of initial capacitance (732.5 F g^?1) after 500 cycles at a current density of 1 A g^?1. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40814.     

Highly filled multilayer thermoplastic/graphene conducting composite structures with high strength and thermal stability for electromagnetic interference shielding applications

Polyvinyl chloride (PVC)/graphene and poly(methyl methacrylate) (PMMA)/graphene nanocomposites were made by solution casting technique with graphene weight fractions of 1, 5, 10, 15, and 20%. Multilayer structures of the composites were made by hot compression technique to study their electromagnetic interference shielding effectiveness (EMI SE). Tensile strength, hardness, and storage modulus of the nanocomposites were studied in relation with graphene weight fraction. There has been a substantial increase in the electrical conductivity and EMI SE of the composites with 15–20% filler loading. Differential thermal analysis of the composites shows improved thermal stability with an increase in graphene loading. PMMA/graphene composites have better thermal stability, whereas PVC/graphene composites have superior mechanical properties. About 2 mm thick multilayer structures of PMMA/graphene and PVC/graphene composites show a maximum EMI SE of 21 dB and 31 dB, respectively, in the X band at 20 wt % graphene loading. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47792.     

Novel electrically conducting polyurethanes with oligoanilines: Synthesis,conductivity, and electrochemical properties

New class of conducting polyurethanes (CPUs) containing oligoanilines, namely tetraaniline (TAni) or trianiline (TriAni), in the backbone have been synthesized and characterized by formal spectral techniques. The unique properties of these CPUs, viz., electronic conductivity and electrochemical activity arising from the presence of oligoaniline units have been evaluated. The basic polyurethane backbone is derived from toluene diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate, and polypropylene glycols of molecular weight 425 and 2000. In the first category of polyurethanes, the prepolymers obtained from the above reactants were chain terminated by TAni in emeraldine base oxidation state. The conductivity of these CPUs films ranged from 1.2 × 10^?5 to 1.77 × 10^?3 S cm^?1. These polymers showed lower conductivity due to the presence of nonconjugated polyurethane segments. These CPUs exhibited slightly different electrochemical activity than that of TAni. The second category of CPUs is obtained from prepolymers by chain extension with TriAni. The conductivity of these polymers is similar to the TAni analogues but are electrochemically inactive. The anticorrosion properties of two of these polymers have also been evaluated in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40794.