Thermally processable conducting polyaniline (original) (raw)
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Macromolecules, 2000
New solution processing systems were studied with the goal to obtain highly conductive polyaniline films with good mechanical properties and its conducting blends with poly(methyl methacrylate). A new dopant, namely, 1,2-benzenedicarboxylic acid, 4-sulfo, 1,2-di(2-ethylhexyl) ester (DEHEPSA), was studied as a protonating agent. It was found that the use of this dopant together with dichloroacetic acid (DCAA) or difluorochloroacetic acid (DFCAA) as solvents leads to films showing conductivities of 180 and 100 S/cm, respectively. Films cast from DCAA are metallic in character down to 220 K. Since the protonation agent used exhibits doping as well as plasticizing properties, the resulting polyaniline films, in addition to high conductivity, show excellent flexibility and much lower glass-transition temperature, T g, (280 K) as compared to polyaniline doped with other protonating agents. Moreover, the same processing system can be used for the fabrication of polyaniline-poly(methyl methacrylate) blends with low percolation threshold (much below 1 wt % of PANI). Upon casting, the overwhelming majority of the solvent can be efficiently removed from the polymer matrix, whereas the remaining residual solvent is strongly bound to the polymer matrix. For this reason, the resulting blends do not show the disadvantages of the blends cast from m-cresol which release the residual solvent upon aging.
Polyaniline. Preparation of a conducting polymer(IUPAC Technical Report)
Pure and Applied Chemistry, 2002
Eight persons from five institutions in different countries carried out polymerizations of aniline following the same preparation protocol. In a "standard" procedure, aniline hydrochloride was oxidized with ammonium peroxydisulfate in aqueous medium at ambient temperature. The yield of polyaniline was higher than 90 % in all cases. The electrical conductivity of polyaniline hydrochloride thus prepared was 4.4 ± 1.7 S cm-1 (average of 59 samples), measured at room temperature. A product with defined electrical properties could be obtained in various laboratories by following the same synthetic procedure. The influence of reduced reaction temperature and increased acidity of the polymerization medium on polyaniline conductivity were also addressed. The conductivity changes occurring during the storage of polyaniline were monitored. The density of polyaniline hydrochloride was 1.329 g cm-3. The average conductivity of corresponding polyaniline bases was 1.4 x108 S cm-1, the ...
Polyaniline Conducting Electroactive Polymers Thermal and Environmental Stability Studies
E-Journal of Chemistry, 2006
In the current studies, polyaniline (PANi) was prepared both chemical and electrochemically in the presence of different bronsted acids from aqueous solutions. The effect of thermal treatment on electrical conductivity, and thermal stability of the PANi conducting polymers were investigated using 4-point probe and TGA techniques respectively. It was found that polymer prepared by CV method is more thermally stable than those prepared by the other electrochemical techniques. In this paper we have also reviewed some fundamental information about synthesis, general properties, diverse applications, thermal and environmental stability of polyaniline conducting polymers.
Materials Letters, 2007
It is demonstrated that polyaniline salt, obtained by simple protonation of its base form with 4,4-bis(4-hydroxy phenyl)-valeric acid (HPVA), combines solution processibility with electrical conductivity. The solution of PANI-HPVA in DMF and m-cresol mixture has been characterized by UV-vis spectroscopy, exhibiting spectral features characteristic of the protonated state. Precipitation of dissolved PANI-HPVA with chloroform, leads to powder of spherical morphology with an average particle size of 400 nm which is amorphous by X-ray. Their conductivity is ca. 10 − 3 S/cm (measured for pressed pellets). Thermogravimetric investigations indicate good thermal stability of this novel form of polyaniline, however some weight loss is observed below 200°C, associated with the removal of minute amounts of solvent entrapped within PANI-HPVA grains in the precipitation process. PANI-HPVA has film forming properties and free standing films (conductivity ca. 10 − 4 S/cm) can be obtained by dissolving the powders in DMF, followed by casting.
2007
It is demonstrated that polyaniline salt, obtained by simple protonation of its base form with 4,4-bis(4-hydroxy phenyl)-valeric acid (HPVA), combines solution processibility with electrical conductivity. The solution of PANI-HPVA in DMF and m-cresol mixture has been characterized by UV-vis spectroscopy, exhibiting spectral features characteristic of the protonated state. Precipitation of dissolved PANI-HPVA with chloroform, leads to powder of spherical morphology with an average particle size of 400 nm which is amorphous by X-ray. Their conductivity is ca. 10 − 3 S/cm (measured for pressed pellets). Thermogravimetric investigations indicate good thermal stability of this novel form of polyaniline, however some weight loss is observed below 200°C, associated with the removal of minute amounts of solvent entrapped within PANI-HPVA grains in the precipitation process. PANI-HPVA has film forming properties and free standing films (conductivity ca. 10 − 4 S/cm) can be obtained by dissolving the powders in DMF, followed by casting.
Synthesis and Characterization of Polyaniline Based Conducting Polymers
Present work deals with the synthesis of Polyaniline, polynitro aniline, poly m-toludine and poly o-toludine polymers by chemical oxidation method using ammonium per sulfate as chemical oxidant. The yield of all polymers was higher than 90%.The synthesized polymeric material have been characterized by FTIR spectroscopy. FTIR and SEM studies of polymer show the structural and slight morphological changes with change in substituent in monomer units
Synthesis and Characterization of Polyaniline Based Conducting Polymers line
Present work deals with the synthesis of Polyaniline, polynitro aniline, poly m-toludine and poly o-toludine polymers by chemical oxidation method using ammonium per sulfate as chemical oxidant. The yield of all polymers was higher than 90%.The synthesized polymeric material have been characterized by FTIR spectroscopy. FTIR and SEM studies of polymer show the structural and slight morphological changes with change in substituent in monomer units.
Journal of Applied Polymer Science, 2002
Poly(o‐toluidine) (POT) and poly(2‐chloroaniline) (P2ClAn) emeraldine salts were synthesized chemically by using formic (HCOOH), acetic (CH3COOH), propionic (C2H5COOH), and boric (H3BO3) acids. Ultraviolet‐visible absorption spectra (UV–Vis) analysis results indicated that POT has the better protonation effects than P2ClAn. Among the POTs synthesized using the four different acids, POT(H3BO3) showed the least protonation effect. The conductivities of prepared polymers were measured by a four‐probe technique. The highest conductivities were obtained in POTs synthesized by using formic, acetic, and propionic acids. Magnetic susceptibility measurements of the polymer salts were analyzed by using Gouy scale and it was found that POT(CH3COOH) and POT(C2H5COOH) salts are of bipolaron structure; other polymer salts are of polaron structure. The characterization of the polymers were investigated by Fourier infrared spectroscopy (FTIR), UV–Vis, thermogravimetric analysis, and scanning electr...