Broadband dielectric spectroscopy of BPDA/ODA polyimide films

Khazaka, Rabih; Locatelli, Marie-Laure; Diaham, Sombel; Bidan, Pierre; Dupuy, Lionel; Grosset, Grégory

doi:10.1088/0022-3727/46/6/065501

Cited by 36 publications

(37 citation statements)

References 35 publications

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“…However, PI films lose their electrical and dielectric properties when they are exposed to high temperature (> 200 °C) becoming semi-insulating materials with high losses and DC conductivity [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of polyimide/boron nitride nanocomposites at high temperature

Diaham¹,

Saysouk²,

Locatelli³

et al. 2014

2014 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)

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The high temperature dielectric properties and electrical conductivity of polyimide/boron nitride (PI/BN) nanocomposite films are investigated as a function of the BN nanofiller size. Whereas in such a temperature range (up to 350 °C) the electrical properties of neat PI are controlled by ionic motions, which make it a semi-insulating material, it has been highlighted the important role of the BN nanofiller size on the reduction of the electrode polarization phenomenon and on the low frequency DC conductivity of PI/BN nanocomposites. Particularly with the smallest BN nanoparticle diameters (95 nm and 40 nm), the dielectric properties changes are strongly attenuated above 200 °C and the DC conductivity is decreased by 1 to 3 orders of magnitude compared to neat PI. For higher nanoparticle diameters (120 nm), the effects are less important. It seems possible to extend the high temperature range of use of PI by using adequate small sizes of BN nanoparticles at low filler content.

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Section: Introductionmentioning

confidence: 99%

Dielectric properties of polyimide/boron nitride nanocomposites at high temperature

Diaham¹,

Saysouk²,

Locatelli³

et al. 2014

2014 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)

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“…The curves for temperatures above −20 °C have been omitted as these are dominated by the appearance of a large conductivity loss and are indicative of Maxwell‐Wagner‐Sillers loss process . The MWS process is associated with charge migration and trapping within the polymer matrix and has been reported by others . X‐ray analysis showed that the materials are essentially amorphous; however, the MWS effect is sensitive to small scale heterogeneity within the polymer structure.…”

Section: Resultsmentioning

confidence: 99%

“…Deviations from these ideal values reflect the distribution of different sites involved in the relaxation process . Khazaka et al has indicated that this dipole process is associated with a localized motion of the chain backbone and its amplitude is sensitive to the presence of adsorbed moisture and has apparent activation energy of 42 kJ mol −1 . A similar relaxation process has been reported previously in the case of poly(ether imide)s with 3‐phthalimide and 4‐phthalimide units .…”

Section: Resultsmentioning

confidence: 99%

“…Optimization of a material for a particular application requires an understanding of the structure: physical property relationships for that material. Dielectric relaxation is a useful probe of the effects of changes in the polymer structure on the extent to which the materials may undergo morphological change as the temperature is changed and is an important property when selecting materials for electronic applications . Changes to groups, which form the backbone structure, can introduce steric hindrance and both influence the chain mobility and inhibit packing.…”

Section: Introductionmentioning

confidence: 99%

“…and these poly (ether imide)s lack the additional interactions associated with the amide structure . Previous dielectric studies of the higher temperatures characteristics of polyimides are dominated by the effects of ionic migration and in a number of systems have made study of the T g process very difficult. Above 0 °C a significant contribution to the dielectric conductivity without a corresponding change in the dielectric permittivity were observed which precluded analysis of the dielectric data above this temperature.…”

Section: Introductionmentioning

confidence: 99%

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Dielectric relaxation studies of some poly(ether imide)s containing main‐chain ethyleneoxide units

Eastmond

Paprotny

Pawson

et al. 2014

J Polym Sci B Polym Phys

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Broad band dielectric relaxation spectra are reported for some poly(ether imide)s based on 2,2‐bis[4′‐(3″,4″‐dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride and 1,2‐bis(4‐aminophenyl) diamines derived from ethylene glycol oligomers of different specific lengths. Spectra were obtained over the temperature range −150–−20 °C and which covers the low temperature relaxation region for these materials. In the case of the polymer with no EO units, a single broad dipole relaxation feature is observed. The introduction of a single CH2CH2O unit significantly broadens the relaxation suggesting the existence of two separate relaxation processes. Increasing the number of EO units per repeat to 3 and 6, allows resolution of two relaxations processes; one due to an oscillatory–librational motion of the imide segment and the other to conformational changes involving the EO sequences. Analysis of the relaxation using the Havriliak‐Negami equation indicates that both processes deviate for the description of a simple dipole relaxation and indicate cooperativity of bond motion in the relaxation process. The ability of a polymer to change its packing density is reflected in changes in the relaxation spectra on annealing and changes in the value of the higher frequency limiting values of the permittivity. The activation energy for dipole reorientation ranges from a value of 34 kJ mol−1 for the relaxation of the dipole associated with the imide relaxation process to a value of 60 kJ mol−1 for the polymer containing 3 EO segments. In this latter polymer, system a lower activation energy process is observed with a magnitude of ∼15 kJ mol−1 associated with conformational changes of the aliphatic ether. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1326–1336

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Influence of change in ether structure on the low temperature dielectric relaxation of some poly(ether imide)

Eastmond

Paprotny

Pethrick

et al. 2014

J of Applied Polymer Sci

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Broad band dielectric relaxation spectra are reported on a range of polymers created by varying the ether segment in a series of poly(ether imide)s. Changes in the structure allow the effects of steric constraints on the local conformational dynamics of the polymer chain to be explored. These changes have a significant effect on the glass transition temperatures of these polymers which range from 245 to over 420°C. In contrast, the low temperature dielectric relaxation behavior of these polymers is very similar and is attributed to cooperative local oscillatory—librational motions. Changes in the stereochemistry effect the amplitude, activation energy for the relaxation process, the packing chain density, and values of the high frequency limiting permittivity, ε∞′. This latter parameter is sensitive to the extent of dipole induced dipole and π‐π electron interactions and is influenced by the packing density. The magnitude of ε∞′ is a very important parameter in determining the suitability of poly(imide)s for electrical applications. The magnitude of ε∞′ increases with the density; however, deviations from this general trend are observed when large nonpolar groups inhibit the interaction of neighboring chains. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41191.

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Broadband dielectric spectroscopy of BPDA/ODA polyimide films

Cited by 36 publications

References 35 publications

Dielectric properties of polyimide/boron nitride nanocomposites at high temperature

Dielectric properties of polyimide/boron nitride nanocomposites at high temperature

Dielectric relaxation studies of some poly(ether imide)s containing main‐chain ethyleneoxide units

Influence of change in ether structure on the low temperature dielectric relaxation of some poly(ether imide)

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