Study on charge transport mechanism and space charge characteristics of polyimide films

Zhou, Liren; Wu, Guangning; Gao, Bo; Zhou, Kai; Liu, J.; Cao, Kesheng

doi:10.1109/tdei.2009.5211868

Cited by 73 publications

(39 citation statements)

References 24 publications

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“…WITH the advantages of high temperature resistance (400 o C ), low temperature tolerance (-269 o C), radiation resistance and excellent dielectric properties, Polyimide (PI) that serves as a typical kind of engineering polymer material has been widely used in different fields, such as the aerial, nuclear, microelectronic industry，turn to turn insulation and turn to ground insulation of inverter-fed motors [1,2]. Many theoretical and experimental studies on its electrical properties have been performed.…”

Section: Introductionmentioning

confidence: 99%

Dynamic behavior of surface charge on direct- fluorinated polyimide films

2013

IEEE Trans. Dielect. Electr. Insul.

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Polyimide film, as a special type of engineering plastic film, is a kind of basic insulating material and is widely applied in the aerial, nuclear, microelectronic industry, turn to turn insulation and turn to ground insulation of inverter-fed motors. However, premature insulation failures occur frequently in motors with the disadvantage of pure PI inherent in all organic materials. The existence of surface charge has a great effect on breakdown characteristic and is the main reason leading to dielectric breakdown. Fluorination as change the chemical component in surface layer of polymers should give rise to the corresponding change in electrical properties of the surface layer thus influence the charge injection from electrodes when they are used as an insulator. This paper presents a study aimed at clarifying the effect of fluorination time on surface charge accumulation and decay behaviors of fluorinated polyimide film. Samples were surface fluorinated in a laboratory vessel at about 328 K (55 ℃) using a F 2 /N 2 mixture with 20% F 2 by volume and 0.05 MPa (500 mbar) for respectively 15, 30, 45 and 60 minutes. Corona charging tests were performed at room temperature with a relative humidity of ~ 40%. The charge distribution was measured by means of an electrostatic voltmeter. Obtained results show the dependence of the charge density as well as the charge decay rate upon the fluorination time of samples, varying as a function of the charge polarity and charging time. It is suggested that the fluorination can significantly improve the decay rate of the surface charge in polyimide films.

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Section: Introductionmentioning

confidence: 99%

Dynamic behavior of surface charge on direct- fluorinated polyimide films

2013

IEEE Trans. Dielect. Electr. Insul.

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“…For the dielectric bulk, space charge results showed that large amounts of trapping states, including deep traps and shallow traps, were introduced in the PI/Al 2 O 3 nanocomposites [42,43]. When the specimens were experimented with corona-discharge existing, a number of electrons and holes were injected into the solid dielectric bulk.…”

Section: Corona-resistant Propertiesmentioning

confidence: 99%

Investigation of temperature effects on voltage endurance for polyimide/Al₂O₃nanodielectrics

Luo

Liu

et al. 2014

IEEE Trans. Dielect. Electr. Insul.

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In order to investigate the effects of inorganic nanofillers on the electrical properties of polyimide (PI), PI/Al 2 O 3 nanocomposites films were prepared via the in-situ polymerization. The hybrids films were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The dielectric behaviors of pure PI and PI/Al 2 O 3 samples were studied as a function of the measured frequencies and temperatures. Meanwhile, the breakdown strength of pure PI and PI/Al 2 O 3 samples measured at 25 and 230 ℃ was analyzed. The corona-resistant lifetime of samples under bipolar continuous square impulse voltage (BCSIV) was performed. With the wt% content of Al 2 O 3 nanoparticles increasing, the real (ε') and imaginary (ε") of relative permittivity present an increasing tendency, while electrical breakdown strength declines obviously. The Al 2 O 3 nanofillers improved the corona-resistant property of PI and the corona-resistant lifetime of PI/Al 2 O 3 sample with 25 wt% (weight percent) of nano-Al 2 O 3 particles is over 23 times longer than that of the pure PI film. Besides, the temperature is an important factor which would significantly influence the electrical properties of pure PI and PI/Al 2 O 3 samples. The elevated temperature would reduce the breakdown voltage and corona-resistant property.

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“…At high temperature, charge injection from the electrode increases. The charges acquire more energy from the thermal excitation and travels deep into the bulk before being trapped [8]. That is to say, the mobility of charges may increase with rise in temperature, which facilitates transport of charge deep within the dielectric before it gets trapped.…”

Section: Trap Depth Estimationmentioning

confidence: 99%

Study of space charge characteristics in epoxy resin and its nanocomposites

Das

Gupta

2010

2010 10th IEEE International Conference on Solid Dielectrics

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In recent times, there has been increased awareness of the fact that space charge within an insulating material considerably governs its dielectric behaviour. In this work, we study the nature of space charge trapping and detrapping in epoxy specimens, with and without nano sized fillers.After application of a poling field for a specific period of time, depolarisation characteristics are obtained by removing the voltage and placing the specimen under short circuit conditions. The release of space charge from deep traps provides a current in the external circuit which is measured using an electrometer. Recombination and transit time is considered to be negligible. Trap depth is calculated on the basis of depolarisation characteristics [1].The trap depth distribution is studied with variation in specimen thickness, applied electric field and temperature. Further, the effect of ageing is studied. In order to estimate the effect of fillers, alumina and other nano fillers are incorporated into the bulk epoxy resin to investigate whether this affects the trapped charge distribution.

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Study on charge transport mechanism and space charge characteristics of polyimide films

Cited by 73 publications

References 24 publications

Dynamic behavior of surface charge on direct- fluorinated polyimide films

Dynamic behavior of surface charge on direct- fluorinated polyimide films

Investigation of temperature effects on voltage endurance for polyimide/Al₂O₃nanodielectrics

Study of space charge characteristics in epoxy resin and its nanocomposites

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Study on charge transport mechanism and space charge characteristics of polyimide films

Cited by 73 publications

References 24 publications

Dynamic behavior of surface charge on direct- fluorinated polyimide films

Dynamic behavior of surface charge on direct- fluorinated polyimide films

Investigation of temperature effects on voltage endurance for polyimide/Al2O3nanodielectrics

Study of space charge characteristics in epoxy resin and its nanocomposites

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Investigation of temperature effects on voltage endurance for polyimide/Al₂O₃nanodielectrics