Effects of the matrix molecular weight on conductivity and dielectric relaxation in plasticized polyaniline/polymethylmethacrylathe blends

Fattoum, A.; Gmati, Fethi; Bohli, Nadra; Arous, M.; Mohamed, Abdellatif Belhadj

doi:10.1088/0022-3727/41/9/095407

Cited by 53 publications

(37 citation statements)

References 46 publications

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“…This formalism was first introduced by McCrum et al [19] and has been successfully ap plied to conducting polymeric systems by a number of investigators [20,21]. According to this formalism complex electric modulus M* is defined as following curve which shifts to higher frequency with the in crease of MMT content in the composites.…”

Section: Resultsmentioning

confidence: 99%

Dielectric properties of polypyrrole/pillared clay nanocomposites

2012

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Dielectric constant ε' and loss factor ε'' were measured in intercalated polypyrrole/aluminum pil lared montmorillonite (PPy/Al PMMT) clay nanocomposites in the frequency range 100 Hz to 1 MHz. The PPy/Al PMMT nanocomposites were prepared by in situ polymerization of pyrrole in aqueous dispersion of varying amounts of (Al PMMT) clay from 0.2 to 10%, using FeCl 3 · 6H 2 O as an oxidant. Formation of the nanocomposite was studied by FTIR and intercalation of PPy in the clay galleries was confirmed by XRD. The nanocomposites exhibited very large values of ε' and ε'' at low frequency which decreased with frequency and increased with the clay content in the samples. Electric modulus formalism exhibited a peak in the fre quency dependence curves of imaginary part of the electric modulus due to conductivity relaxation process. The peak of conductivity relaxation shifted towards higher frequencies and the magnitude of relaxation decreased with the increase of MMT content in the composites.

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Section: Resultsmentioning

confidence: 99%

Dielectric properties of polypyrrole/pillared clay nanocomposites

2012

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“…The complex dielectric per mittivity is defined by ε(ω, T) = ε'(ω, T) -iε''(ω, T) Where ε' defines the dispersion factor and ε'' defines the global loss factor. The global loss factor covers dipolar, interfacial (Maxwell Wagner) and conduction loss contribution; it is expressed as a sum of three terms [20][21][22]:…”

Section: Electric Behaviormentioning

confidence: 99%

“…The conduction loss factor is defined by [19][20][21][22]: (7) To take in account the conductivity and the elec trode effects in the dielectric response, it is widely accepted to fit the experimental data of the global loss factor in low frequency region to a power law defined by A/ω n . If the electrode effect is negligible the expo nent n becomes close to 1 and A close to σ dc .…”

Section: Electric Behaviormentioning

confidence: 99%

Conductivity and dielectric relaxation in crosslinked PVA by oxalic and citric acids

et al. 2015

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In this work we investigated polyvinyl alcohol films which we crosslinked at various crosslinking degrees by oxalic and citric acids for the fuel cell applications. We studied the effects of the crosslinking on structure, thermal properties, electric conductivity and dielectric relaxations. The glass transition tempera ture is increased indicating the lowering of the local mobility of the polymer chains. X ray diffraction showed the presence of non dissociated acid phases in dried samples. The Dc conductivity increases by increasing both the relative humidity and the temperature obeying to an Arrhenius law with activation energy compatible with proton conductivity type. The Ac conductivity studied between 10 -1 Hz and 1 MHz showed a power law response in the high frequency range. This behavior characterizes the charge transport in disordered materi als. At low frequencies the Ac conductivity is governed by the electrode/sample interface polarization. The use of the dielectric permittivity indicates the presence of a relaxation process attributed to electrode/sample interface polarization and another relaxation process attributed to alpha relaxation of the polyvinyl alcohol chains.

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“…We analyze the dielectric relaxation by using the complex dielectric permittivity defined by: (4) where ε' defines the dispersion factor and ε'' defines the global loss factor. In general, the global loss factor is expressed as a sum of three terms [21,22]:…”

Section: Conductivitymentioning

confidence: 99%

“…This term, proportional to the inverse of the frequency, increases as the frequency decreases. For materials having significant dc conductivity, this term may cause the camouflage of eventual dielectric relaxation peaks expected in the global loss factor curves at low fre quencies [21][22][23].…”

Section: Conductivitymentioning

confidence: 99%

Conductivity and dielectric relaxation in various polyvinyl alcohol/ammonium salt composites

Fattoum

Arous

2014

Polym. Sci. Ser. A

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We studied electrical conductivity and dielectric relaxation in polyvinyl alcohol/ammonium chlo ride and polyvinyl alcohol/ammonium acetate composite films. Infrared absorbance showed the presence of H bonding interaction between the salt and the polymer. X ray diffraction showed the reduction of the grain size of ordered regions in the polymer matrix after adding salt. Thermo gravimetric analysis (TGA) showed water wt% content between 4.2 and 5.8%. Differential Scanning Calorimetry (DSC) showed the decrease of the glass transition due to retained water indicating its plasticizer effect. The ac conductivity studied in the frequency range from 10 -1 Hz to 1 MHz and the temperature range from 10 to 150°C is described by the uni versal law of Jonsher characterizing the charge transport in disordered materials. With NH 4 Cl inclusion, the dc conductivity showed a higher value in the vicinity of 4% but with NH 4 CH 3 CO 2 the dc conductivity decreases monotonically by increasing the salt amount. By using the dielectric permittivity and dielectric modulus we detected three relaxation processes which we attributed to electrode/sample polarization, alpha relaxation and conductivity relaxation respectively.

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Effects of the matrix molecular weight on conductivity and dielectric relaxation in plasticized polyaniline/polymethylmethacrylathe blends

Cited by 53 publications

References 46 publications

Dielectric properties of polypyrrole/pillared clay nanocomposites

Dielectric properties of polypyrrole/pillared clay nanocomposites

Conductivity and dielectric relaxation in crosslinked PVA by oxalic and citric acids

Conductivity and dielectric relaxation in various polyvinyl alcohol/ammonium salt composites

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