Space charge relaxation in polyetherimides by the electric modulus formalism

Mudarra, M.; Belana, J.; Cañadas, J. C.; Diego, J. M.; Sellarès, J.; Díaz‐Calleja, Ricardo; Sanchı́s, M. J.

doi:10.1063/1.1312839

Cited by 30 publications

(32 citation statements)

References 21 publications

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“…The parameter r r decreases when the initial field is increased, so it seems more difficult for carriers to scape from traps when a higher initial potential is applied. As we are working for relatively short times The parameter α can be associated with the sublinear power-law observed in conductivity in the frequency domain [34][35][36][37]. This power-law conduction regime is associated with the slowing down of the relaxation process in the frequency domain as a result of the cooperative effects, in the same way as the KWW function does in the time domain.…”

Section: Dispersive Mobilitymentioning

confidence: 99%

Study of dispersive mobility in polyimide by surface voltage decay measurements

Aragoneses¹,

Mudarra²,

Belana³

et al. 2008

Polymer

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In order to study charge trapping and transport in polyimide, we have submitted samples of Kapton HN to corona charging and measured its surface potential decay with an electrostatic voltmeter. We propose a two terms mobility to explain the experimental data: a non dispersive contribution based on Toomer and Lewis model added to a dispersive process, which is associated with the disordered structure of the material. The non-dispersive model alone did not fit well to the data for short times, but our assumption makes the theoretical expresion fit succesfully to the experimental data. Some important parameters related to the charge transport properties of the material are determined and discussed.

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Section: Dispersive Mobilitymentioning

confidence: 99%

Study of dispersive mobility in polyimide by surface voltage decay measurements

Aragoneses¹,

Mudarra²,

Belana³

et al. 2008

Polymer

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“…Figure 6 shows an Arrhenius plot of the conductivity where it can be seen that it is thermally activated. This increase has been attributed to an increase of carrier mobility [13]. Conductivity can be fitted to The activation energies and preexponential factors can be seen in Table 5.…”

Section: T(ºc)mentioning

confidence: 99%

“…Instead, in the electric modulus it appears as peak allowing an easier interpretation of the data. The electric modulus formalism has been used to study the conductivity relaxation in polymers [13,14], glasses [15], crystals [16], ceramics [17] and composites [18,19], among other materials, as epoxy resines [20].…”

Section: Polyetherimide (Pei) Is An Amorphousmentioning

confidence: 99%

Sublinear dispersive conductivity in polyetherimides by the electric modulus formalism

Mudarra

Sellarès

Cañadas

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

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Dynamic Electrical Analysis shows that the electrical properties of polyetherimide at temperatures above the glass transition are strongly influenced by space charge. We have studied space charge relaxation in two commercial grades of polyetherimide, Ultem 1000 and Ultem 5000, using this technique. The electric modulus formalism has been used to interpret their conductive properties. In both grades of polyetherimide, asymmetric Argand plots are observed, which are related to a sublinear power-law dependency (ω n with n<1) in the real part of the conductivity. This behavior is attributed to correlated hopping. The imaginary part of the electric modulus exhibits a peak in the low frequency range associated with conduction. The modelisation of this peak allows us to obtain the dependence, among other parameters, of the conductivity (σ 0 ), the fractional exponent (n) and the crossover frequency (ω p ) on the temperature. The α relaxation, which appears at higher frequencies, has also to be modeled since it overlaps the conductivity relaxation. The study of the parameters in terms of the temperature allows us to identify the ones that are thermally activated. The difference between the conductivity relaxation time and the Maxwell relaxation time indicates the presence of deep traps. The coupling model points out that the correlation of the ionic motion diminishes with temperature, probably due to increasing disorder due to thermal agitation.

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“…Studies on the effects of these parameters could give information on material reliability. Numerous investigations on PEI properties have been made by researchers [1][2][3][4][5][6][7][8][9] . The relaxational behaviour of this material is one of the researched topics.…”

Section: Introductionmentioning

confidence: 99%

“…Polyetherimide (PEI) is suitable for industrial applications, including electrical insulation [1][2][3] . Its properties are influenced by environmental parameters such as radiations, pressure, temperature.…”

Section: Introductionmentioning

confidence: 99%

Heating Effects on Structural and Electrical Properties of Polyetherimide

Nima¹

2009

American Journal of Engineering and Applied Sciences

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Problem statement: Polyetherimide (PEI) has several uses such as electrical insulation. It can undergo different constraints like heat or high voltage which influence its performances as insulator. In this study, the effects of heating on structural and electrical properties of polyetherimide (Ultem 1000) are studied. Approach: PEI samples were heated at different temperatures below the glass transition temperature (175, 190 and 205°C). Different complementary techniques were used to investigate structural alterations and dielectric relaxations. These are infrared (IR) spectroscopy, Differential Scanning Calorimetry (DSC), Thermally Stimulated Depolarisation Current (TSDC) technique and Dielectric Spectroscopy (DS). Results: Physical ageing was revealed in heated samples by DSC analysis. DS and TSDC results have shown that dipolar relaxations are affected by heating. The amount of relaxing dipoles decreases when the material is heated at 190°C. Conclusion/Recommendations: The heating of polyetherimide at 190°C leads to a stabilisation of charges in deeper energetic levels which influences the insulating character of the material.

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Space charge relaxation in polyetherimides by the electric modulus formalism

Cited by 30 publications

References 21 publications

Study of dispersive mobility in polyimide by surface voltage decay measurements

Study of dispersive mobility in polyimide by surface voltage decay measurements

Sublinear dispersive conductivity in polyetherimides by the electric modulus formalism

Heating Effects on Structural and Electrical Properties of Polyetherimide

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