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     

Soluble polypyrrole copolymers

A new class of dimethyl formamide (DMF)– and acetone‐soluble conducting pyrrole–ketonic resin copolymers has been developed. This was accomplished by oxidatively polymerizing pyrrole monomer by Ce(IV) salt in the presence of methyl ethyl ketone formaldehyde resin (MEKF–R). The resulting copolymers were readily dissolved in DMF and acetone. These products were characterized by FTIR and UV‐visible spectroscopy, conductivity, four‐probe conductivity, viscosity, and DSC measurements. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1098–1106, 2001     

Immobilization of invertase in conducting polypyrrole/PMMA‐co‐PMTM graft copolymers

In this study, invertase was immobilized in copolymer electrodes constructed. Three different types of polymethyl methacrylate‐co‐polymethyl thienyl methacrylate matrices were used to obtain copolymers that were characterized by FT‐IR spectroscopy. Immobilization of enzymes was carried out by the entrapment of the enzyme in conducting polymer matrices during electrochemical polymerization of pyrrole through thiophene moieties of polymers. Immobilization of the enzyme was achieved by application of 1.0 V constant potential on a platinum electrode for 30 min in solution. The effects of temperature and pH on the activity of the enzyme electrodes were examined and operational stability studies were done. The changes in the maximum reaction rate and the variations in the Michaelis–Menten constant were studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 502–507, 2005     

Synthesis and properties of conducting polypyrrole,polyalkylanilines, and composites of polypyrrole and poly(2‐ethylaniline)

Conducting polymers of alkylanilines, pyrrole, and their conducting composites were synthesized by oxidation polymerization. The oxidants used were KIO₃ and FeCl₃ for the polyalkylanilines and polypyrrole (PPy), respectively. Among the polyalkylanilines synthesized with KIO₃ salt, the highest conductivity was obtained with poly(2‐ethylaniline) (P2EAn) with a value of 4.10 × 10^?5 S/cm. The highest yield was obtained with poly(N‐methylaniline) with a value of 87%. We prepared the conducting composites (PPy/P2EAn and P2EAn/PPy) by changing synthesis order of P2EAn and PPy. The electrically conducting polymers were characterized by IR spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis, and X‐ray diffraction spectroscopy. From the results, we determined that the properties of the composites were dependent on the synthesis order of the polymers. The thermal degradation temperature of PPy was observed to be higher than that of the other polymers and composites. We determined from X‐ray results that the structures of the homopolymers and composites had amorphous regions (88–95%) and crystal regions (5–12%). From the Gouy balance magnetic measurements, we found that the polymers and composites were bipolaron conducting mechanisms. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 241–249, 2006     

Novel route to pure and composite fibers of polypyrrole

An organic salt (FeAOT) is synthesized by the reaction of sodium 1,4‐bis(2‐ethylhexyl)sulfosuccinate (AOT) and ferric chloride. It is fabricated into fibers by manual drawing and electrospinning. Long polypyrrole (PPy) fibers are obtained for the first time by a vapor deposition reaction of pyrrole on the FeAOT fibers, and this technique is extended to the synthesis of PPy composite fibers with multiwalled carbon nanotubes (PPy–MWCNT fibers). The PPy and PPy–MWCNT fibers have a nanoporous morphology, a conductivity of 10–15 S cm^?1, and a tensile strength of 12–43 MPa. The electrochemistry and current–voltage characteristics of the PPy fibers are also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1490–1494, 2007     

Kinetics of the thermal degradation and thermal stability of conductive silicone rubber filled with conductive carbon black

The kinetics of the thermal degradation and thermal stability of conductive silicone rubber filled with conductive carbon black was investigated by thermogravimetric analysis in a flowing nitrogen atmosphere at a heating rate of 5°C/min. The rate parameters were evaluated by the method of Freeman–Carroll. The results show that the thermal degradation of conductive silicone rubber begins at about 350°C and ends at about 600°C. The thermal degradation is multistage, in which zero‐order reactions are principal. The kinetics of the thermal degradation of conductive silicone rubber has relevance to its loading of conductive carbon black. The activation energies are temperature‐sensitive and their sensitivity to temperature becomes weak as temperature increases. In addition, the conductive silicone rubber filled with conductive carbon black has better thermal stability than that of silicone rubber without any fillers. Also, conductive silicone rubber filled with conductive carbon black has better thermal stability than that of silicone rubber filled with the same amount of silica. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1548–1554, 2003     

Humic acid/polypyrrole on a paraffin‐impregnated graphite electrode and its use in arsenic extraction

A novel and simple electrode with rapid preparation was developed with humic acid (HA) and polypyrrole (PPy) films. The method for modified electrode preparation embraced the abrasive transfer technique on a paraffin‐impregnated graphite electrode (PIGE) followed by the electrochemical incorporation of a PPy polymeric film upon bare PIGE and PIGE/HA electrodes. Cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry were used for the study of the modified electrodes. Morphological characterization was performed by scanning electron microscopy. The obtained results demonstrated that the presence of HA did not affect the electrical properties of the system but indeed provoked changes in the polymer morphology, turning it more granular. Next, PIGE/HA/PPy was tested in arsenic solutions [As(V)] because arsenic contamination of water is an important worldwide environmental issue because of the sources of arsenic contamination of water come from both natural processes and anthropogenic activities. The modified electrode displayed good and reversible extraction properties toward the analyte in acid medium and was 18% more efficient than a previously reported PPy‐modified electrode (PIGE/PPy). From an environmental standpoint, this novel application of conductive polymer properties with the chelating capacity of humic substances constitutes a first step in the development of more efficient technologies for the removal of contaminants present in soil–water media. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

DC current voltage characteristics of silicone rubber filled with conductive carbon black

Direct current (DC) current‐voltage (I‐V) characteristics of silicone rubber filled with conductive carbon black (CB) were studied at room temperature in the voltage range of 1–46 V. The current‐voltage relationship can be expressed as I = AV^B, where A and B are constants that show capability and property of electrical conduction, respectively. The I‐V curve can be divided into ohmic and nonohmic regions. In nonohmic region, B < 1, and the resistance increases with the rise of voltage. Higher CB loading leads to lower transforming voltage from ohmic to nonohmic region and much deviation from Ohm's law. The reason for this deviation is the unbalance between the heat generated and the heat loss of conductive silicone rubber during the measurement. When the heat effect is eliminated completely, the electrical conduction is ohmic. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 587–592, 2004     

Chemical synthesis,characterization, and direct‐current conductivity studies of polypyrrole/γ‐Fe2O3 composites

The in situ polymerization of pyrrole was carried out in the presence of γ‐Fe₂O₃ to synthesize polypyrrole/γ‐Fe₂O₃ composites by a chemical oxidation method. The polypyrrole/γ‐Fe₂O₃ composites were synthesized with various compositions, including 10, 20, 30, 40, and 50 wt % γ‐Fe₂O₃ in pyrrole. The polypyrrole/γ‐Fe₂O₃ composites were characterized with X‐ray diffractometry and infrared spectroscopy. The surface morphology of these composites was studied with scanning electron microscopy. The direct‐current conductivity was studied from 40 to 200°C. The dimensions of the γ‐Fe₂O₃ particles in the matrix had a greater influence on the conductivity values. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2797–2801, 2007     

Application of polypyrrole to flexible substrates

Conducting polymers such as polypyrrole may be useful in smart packaging products, provided application methods can be developed that circumvent the insolubility and infusibility of these materials. Experiments were conducted in five research areas relevant to the application of polypyrrole to nonrigid substrates. The studies reveal that application of polypyrrole from the liquid phase, either by deposition from depleted bulk solution or inkjet printing dispersions, is unlikely to give films as regular as those produced by vapor phase polymerization. Using the latter approach, two potential methods of applying patterned polypyrrole films to nonrigid substrates were developed. The first used hypochlorite to pattern a continuous film of polypyrrole, previously applied by vapor phase polymerization. The second used inkjet printing to apply an oxidant solution, whose pH had been raised with a volatile base, to nonrigid substrates. The higher pH reduced corrosion of the print head, increasing the lifetime of printers exposed to oxidative compounds. The base was subsequently evaporated by heating, and the dried oxidant used as a template for vapor phase polymerization of polypyrrole. This method gave smooth, shiny and adherent polypyrrole films on papers and polyester transparency, with high resolution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3938–3947, 2007     

Conductive effect of an electronic/ionic complex conductivity modifier for silicone elastomers

This study examined silicone, which demonstrated an ionic/electronic compounding conductivity effect through the complexation of polypyrrole (Ppy), carbon black (CB), and a poly(propylene oxide)–poly(ethylene oxide) copolymer with 20 wt % LiClO₄ (PEL). Rigid‐body pendulum rheometry was used to observe the processing conditions for the polymer blends, and energy‐dispersive X‐ray spectrometry was used to analyze the distribution depth of the polymer blend surfaces for Ppy. In addition, a digital electrometer was used to test the surface resistance of the composites, and an impedance meter was used to test the dielectric constant and loss factor. The results showed that PEL‐obstructed silicone molecular chain crosslinking, transformed from liquid to solid films, required a higher temperature for curing than silicone because the linear molecular structure of the polymer electrolyte was wound around the silicone polymer network structure, forming a semi‐interpenetrating network. This showed that the Ppy molecule could permeate SP10 blends more deeply. After the silicone was treated with the PEL modifier, the conductivity of Ppy was obstructed. On the other hand, the conductivity of CB showed no significant difference in the SP10 blends. Therefore, after the silicone matrix treatment of the electronic/ionic complex conduction process, there was no incremental effect on the conductivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 711–720, 2005     

Potassium persulfate-mediated preparation of conducting polypyrrole/polyacrylonitrile composite fibers: Humidity and temperature-sensing properties

Conducting polypyrrole (PPy)/polyacrylonitrile (PAN) composite fibers were prepared by the polymerization of pyrrole in the presence of PAN fibers with potassium persulfate in an acidic aqueous solution. We obtained composite fibers containing concentrations of PPy as high as 1.14% and having surface resistivities as low as 0.6 kΩ/cm² by changing the polymerization parameters, including the temperature and concentrations of pyrrole and oxidant. The tensile strength of 10.02 N/m² and breaking elongation of 32.68% for the pure PAN fiber increased up to 10.45 N/m² and 33.23%, respectively, for the composite fiber containing 0.13% PPy. The change in the resistivity of the PPy/PAN composite fiber during heating–cooling cycles in the temperature range of +5 to 120°C was examined. Scanning electron microscopy and optical microscopy images of the composite fibers showed that the PPy coating was restricted to the surfaces of the PAN fibers. Surface resistivity measurements, Fourier transform infrared spectroscopy, and thermogravimetric analysis techniques were also used to characterize the composite fibers. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Soluble and conductive copolymers from 1‐(hydroxyalkyl) pyrroles

1‐Substituted pyrroles such as 1‐(hydroxymethyl)pyrrole, 1‐(3‐hydroxypropyl) pyrrole, 1‐H‐1‐pyrrolylmethyl 4‐methyl‐1‐benzenesulfonate, 1‐H‐1‐pyrrolylpropyl 4‐methyl‐1‐benzenesulfonate, and 1‐H‐pyrrolylmethyloctanoate were synthesized and oxidative polymerized and copolymerized with pyrrole by using (NH₄)₂Ce(NO₃)₆ and FeCl₃. Some of the copolymers were slightly soluble in DMF and DMSO. The products were characterized by FTIR, ¹H‐NMR, and four‐point probe conductivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1830–1834, 2005     

Supercritical carbon dioxide assisted preparation of conductive polypyrrole/cellulose diacetate composites

Supercritical carbon dioxide (SC‐CO₂) has been used to assist the preparation of conductive polypyrrole/cellulose diacetate (PPy/CDa) composites by in situ chemical oxidative polymerization. The morphology and conductivity of resulted composites were investigated with scanning electron microscopy and four‐probe method, respectively. With the assistance of strong swelling effect of SC‐CO₂, composite films were obtained with a macroscopically homogeneous structure and conductivity up to 10^?1 S cm^?1 order of magnitude. Increasing the pressure of SC‐CO₂ increased conductivity, while increasing the temperature decreased conductivity. For comparison, PPy/CDa composite was also prepared with conventional oxidative method in aqueous solution. From the viewpoint of conductivity and environmental protection, the SC‐CO₂ method showed its superiority over the conventional one. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4575–4580, 2006     

Preparation and characterization of polypyrrole/modified multiwalled carbon nanotube nanocomposites polymerized in situ in the presence of barium titanate

Polypyrrole (PPy) composites were prepared with both unmodified and amine‐modified multiwalled carbon nanotubes (MWCNTs) in the presence and absence of barium titanate (BaTiO₃) by in situ oxidative polymerization. A uniform coating of PPy on the MWCNTs and BaTiO₃ surfaces was confirmed by field emission scanning electron microscopy and high‐resolution transmission electron microscopy images. The structure of the pure and amine‐modified MWCNTs were identified by Fourier transform infrared spectroscopy. The incorporation of BaTiO₃ enhanced the thermal stability and capacitance properties of the composites. The maximum specific capacitance and energy density values found for the PPy/amine‐modified MWCNT/BaTiO₃ composites were 155.5 F/g and 21.6 W h/kg, respectively, at a scan rate of 10 mV/s. The maximum power density was found to be 385.7 W/kg for the same composite at a scan rate of 200 mV/s. Furthermore, the impedance spectra of the composites showed moderate capacitive behavior. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Molecularly imprinted polypyrrole prepared by electrodeposition for the selective recognition of tryptophan enantiomers

Herein we report the electrosynthesis of polypyrrole with L ‐tryptophan (L ‐Trp) as a template to prepare molecularly imprinted polymers (MIPs). Overoxidized polypyrrole films with cavities complementary to the template were used for the enantioselective detection of L ‐Trp and D ‐tryptophan (D ‐Trp). Important parameters, such as the electropolymerization potential, overoxidization potential and time, thickness of the polypyrrole films, and scanning rate of the stripping voltammetric experiments, were varied to achieve an optimum sensor response. We found that L ‐Trp was inserted about 2 times higher into the imprinted polymer film than D ‐Trp. Also, in this study, an electrochemical quartz crystal microbalance technique was used to investigate the performance of overoxidized polypyrrole films. The enantioselectivity of the MIPs was attributed to the cavities in the imprinted films, which were complementary to the target molecules, both in shape and in positioning of the functional groups. The results also suggest the feasibility of preparing MIPs by electropolymerization for the enantioselective recognition of other amino acid enantiomers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Morphology,structure, and conductivity of polypyrrole prepared in the presence of mixed surfactants in aqueous solutions

Polypyrrole (PPy) was prepared from different mixed‐surfactant solutions with ammonium persulfate as an oxidant. Three types of combinations were selected, including cationic/anionic, cationic/nonionic, and anionic/nonionic mixed‐surfactant solutions. The surfactants used in the experiments included cetyltrimethylammonium bromide (cationic surfactant), sodium dodecyl sulfate (anionic surfactant), sodium dodecyl sulfonic acid salt (anionic surfactant), poly(vinyl pyrrolidone) (nonionic surfactant), and poly(ethylene glycol) (nonionic surfactant). The morphology, structure, and conductivity of the resulting PPy were investigated in detail with scanning electron microscopy, Fourier transform infrared spectra, and the typical four‐probe method, respectively. The results showed that the interaction between the different surfactants and the interaction between the surfactants and the polymer influenced the morphology, structure, and conductivity of the resulting polymer to different degrees. The cationic surfactant favored the formation of nanofibers, the addition of anionic surfactants produced agglomeration but enhanced the doping level and conductivity, and the presence of a nonionic surfactant weakened the interaction between the other surfactant and the polymer in the system. In comparison with the results for monosurfactant solutions, the polymerization of pyrrole in mixed‐surfactant solutions could modulate the morphologies of PPy, which ranged from nanofibers of different lengths to nanoparticles showing various states of aggregation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1987–1996, 2007     

Electrochemical synthesis and characterization of conducting copolymers of biphenyl with pyrrole

Copolymer films of biphenyl and pyrrole were synthesized by electrochemical polymerization. The influence of the applied potential used for the electropolymerization on the structure, morphology, electrical conductivity, and stability of the films was examined. From the analysis of the current–time curves, it was found that the growth of the copolymer films starts immediately. The films were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, X-ray diffraction analysis, and scanning electron microscopy–energy-dispersive X-ray analysis, and their electrical conductivity (σ), energy gap (E_g), and electrochemical stability were also determined. Based on the results, the copolymers were classified into three groups. The first includes the (PP-PPy)_0.80 copolymer synthesized at the lowest potential E_ox (0.80 V), having the highest ratio R (R = 0.35) of quinoid to benzenoid rings (calculated from FTIR), the highest value of σ (σ = 0.9 S/cm), the lowest E_g (E_g = 1.20 eV), and has compact morphology. The second group concerns the copolymers synthesized at higher potential (0.82 up to 0.86 V), having lower R (∼ 0.20), lower σ (below 0.4 S/cm), higher E_g (∼ 1.35 eV), and they are less compact with many pores. The third group includes the copolymers synthesized at even higher applied potential (0.88 and 0.90 V), having even lower R values (∼ 0.10), significantly lower σ (∼ 10⁻³ S/cm), even higher E_g (∼ 1.70 eV), and they are very porous. The applied potential during electropolymerization strongly affects the properties of the synthesized copolymers. Because of the combination of high conductivity, low energy gap, and partial solubility with significant electrochemical stability, these new copolymers are attractive candidates for many applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrochemical preparation and properties of polypyrrole and its blend with poly(vinyl sulfonate) doped with perchlorate anions

In this article, we report polypyrrole (PPy)/poly(vinyl sulfonate) (PVS) and PPy/perchlorate (ClO) composite films generated by the electrochemical oxidation of pyrrole on a glassy carbon electrode (GCE) in an aqueous solution. The response of the produced films to an applied potential at 0.7 V was obtained by a cyclic voltammetry study in acetonitrile media. The films were significantly similar in their electrochemical behavior when ClO ions doped during the redox process. We concluded that with an increasing number of cycles, the anodic current increased because the number of the electroactive participants transported in the copolymer matrix was increased. Theoretical studies based on the Nernst and Butler–Volmer equations indicated that the ClO ion was transported during the oxidation/reduction process of the PPY/PVS and PPY/ClO films. The produced films were characterized further by means of IR spectroscopy, electrochemical impedance spectroscopy, and scanning electron microscopy to verify that the anion of ClO was doped into the copolymer matrix as well. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of polypyrrole rod doped with p‐toluenesulfonic acid via micelle formation

Rod‐type polypyrrole (PPY) doped with p‐toluenesulfonic acid (TSA) was synthesized by chemical oxidative polymerization via a self‐assembly process. The shape of the PPY particles is mainly determined by the ratio of TSA/pyrrole (PY) and feed rate of the oxidant. Particle of different shapes (rod, grain, and partially rod) exhibit differences in morphology, electrical properties, dispersity, and thermal properties. Wide‐angle X‐ray diffraction patterning analysis was used to investigate the mechanism of rod formation. The effect of the TSA concentration on the PPY structure was investigated using Fourier transform infrared spectroscopy. The PPY rods doped with TSA exhibited better electrical conductivity than granular PPY doped with TSA, and their dispersity and thermal stability were also higher. Self‐orientation of PPY in the micelles of TSA and high crystallinity of the rod particles led to improved thermal stability. Hence, the decomposition temperature of the polymer chain was considerably increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008