The influence of moisture on the electrical properties of crosslinked polyethylene/silica nanocomposites

Hui, L.; Schadler, Linda S.; Nelson, J. K.

doi:10.1109/tdei.2013.6508768

Cited by 88 publications

(37 citation statements)

References 58 publications

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“…However, if the true structure were to differ markedly from the ideal, then the presence of many polar surface groups would be expected to lead to hydrogen bonds with any labile polar species present in the system, most notably, water. Many studies of water uptake and accumulation at nanoparticle/polyethylene interfaces have been undertaken [32][33][34], which have demonstrated that the presence of the resulting bound water is readily seen in the dielectric spectrum and that the presence of this water has a marked detrimental influence on electrical performance. In contrast, the systems considered here interact extremely weakly with water, which implies the presence of few accessible hydroxyl groups at hBN/polyethylene interfaces [35]; this is discussed fully elsewhere [36].…”

Section: Resultsmentioning

confidence: 99%

Enhanced dielectric properties of polyethylene/hexagonal boron nitride nanocomposites

et al. 2017

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A range of nanocomposites based on a polyethylene polymer and hexagonal boron nitride (hBN) filler have been explored in this study. The dielectric properties of the nanocomposites, which consisted of 2, 5, 10, 20 and 30 wt% of hBN, have been compared to the dielectric properties of the unfilled polyethylene blend. Scanning electron microscopy revealed that the hBN was uniformly distributed in the polyethylene matrix, although large amounts of agglomerates were present in the nanocomposites containing more than 10 wt% of hBN. The incorporation of hBN into polyethylene resulted in a highly disordered morphology in comparison with the unfilled polyethylene, in which this effect was more pronounced with increasing hBN content. This is consistent with the increasing crystallisation temperature as the hBN content increases, as shown by differential scanning calorimetry, where the hBN acted as a highly effective nucleating due to the strong interactions between the polyethylene and the hBN. This strong interaction is again reflected in the thermal decomposition temperature which similarly increases with increasing hBN content. The study demonstrates the remarkable electrical properties of the prepared nanocomposites, where the breakdown strength monotonically increased as a function of hBN content, even with a very high 30 wt% of hBN. The improvement in electrical properties, even at high hBN concentrations, is contradictory to the reported results in the literature and is mainly attributed to the hydrophobic surface of the hBN particles.

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Section: Resultsmentioning

confidence: 99%

Enhanced dielectric properties of polyethylene/hexagonal boron nitride nanocomposites

et al. 2017

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“…Hui et al [124,125] investigated the dielectric behavior of XLPE/silica nanocomposites in humid environments. Compared to the unfilled XLPE, nanocomposites containing silica particles were found to show increased moisture uptake due to filler inclusion.…”

Section: Permittivity and Loss Factor Of Nanocompositesmentioning

confidence: 99%

Polyethylene Nanocomposites for Power Cable Insulations

et al. 2018

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This review represents a comprehensive study of nanocomposites for power cables insulations based on thermoplastic polymers such as polyethylene congeners like LDPE, HDPE and XLPE, which is complemented by original results. Particular focus lies on the structure-property relationships of nanocomposites and the materials’ design with the corresponding electrical properties. The critical factors, which contribute to the degradation or improvement of the electrical performance of such cable insulations, are discussed in detail; in particular, properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, space charge, electrical and water tree resistance behavior and electric breakdown of such nanocomposites based on thermoplastic polymers are described and referred to the composites’ structures. This review is motivated by the fact that the development of polymer nanocomposites for power cables insulation is based on understanding more closely the aging mechanisms and the behavior of nanocomposites under operating stresses.

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“…This increase in 00 r at low frequencies might be due to a higher DC conductivity of these samples or might be the high frequency tail of a relaxation that peaks at a frequency below our accessible range. Many studies have shown that the addition of nanoparticles imparts a new mid-or lowfrequency relaxation peak that moves to higher frequencies with increasing temperature [36,52] or with absorbed water [53][54][55]. Related to the materials considered here, Hosier [56] has recently reported that the addition of Si 3 N 4 nanoparticles into a polyethylene matrix causes a new relaxation that shifts to higher frequency with higher water uptake; Yeung [36] has also observed a similar feature that peaks at higher frequencies for higher temperatures, for the same epoxy matrix when filled with nanosilica.…”

Section: Dielectric Spectramentioning

confidence: 99%

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

et al. 2017

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The addition of nanofillers can have a significant influence on the resin stoichiometry of thermosetting polymer systems. Based on differential scanning calorimetry (DSC) results, it is estimated that the inclusion of 2 and 5 wt% of silicon nitride nanofiller displaces the resin/hardener stoichiometry of an epoxy/amine network by 6.5 and 18%, respectively. Dielectric spectroscopy results confirm the above findings, in that the spectra of the nanocomposite samples were found to be equivalent to the spectra of unfilled samples when the above stoichiometric effect was taken into account. Therefore, this study provides clear evidence that the presence of a nanofiller can directly and significantly affect the curing process of an epoxy network. Consequently, this should always be considered when introducing nanofillers into thermosetting matrices. These results indicate the presence of covalent bonding between the nanoparticles and the surrounding polymer and, therefore, provide an opportunity to explore the influence of this bonding on the molecular dynamics of the polymer layer around the particles. However, the obtained DSC and dielectric spectroscopy results suggest that, in the system considered here, either the covalent bonding does not have an appreciable influence on the segmental dynamics of the polymer, as revealed by these techniques, or that the thickness of the affected layer is less than 1 nm and therefore too small to be distinguished from experimental uncertainties.

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The influence of moisture on the electrical properties of crosslinked polyethylene/silica nanocomposites

Cited by 88 publications

References 58 publications

Enhanced dielectric properties of polyethylene/hexagonal boron nitride nanocomposites

Enhanced dielectric properties of polyethylene/hexagonal boron nitride nanocomposites

Polyethylene Nanocomposites for Power Cable Insulations

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

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