On additives, morphological evolution and dielectric breakdown in low density polyethylene

Vaughan, A. S.; Zhao, Yue; Barré, Luke; Sutton, S.J.; Swingler, S.G.

doi:10.1016/s0014-3057(02)00194-5

Cited by 43 publications

(25 citation statements)

References 47 publications

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“…It is well known that the cross-linking of semicrystalline polymers such as PCL significantly modifies their physical properties with respect to those of the linear precursor, particularly their melting and crystallization temperatures. [35,36] In contrast, when PCL 4 is added, the resulting PUR networks are still semicrystalline, as indicated by the data in Table 1. This is supported by the appearance of a relatively high melting temperature (T m ) between 44 and 48 8C, together with a relatively high melting enthalpy (DH m ).…”

mentioning

confidence: 98%

Design of Cross‐Linked Semicrystalline Poly(ε‐caprolactone)‐Based Networks with One‐Way and Two‐Way Shape‐Memory Properties through Diels–Alder Reactions

Raquez

Vanderstappen

Meyer

et al. 2011

Chemistry A European J

117

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Cross-linked poly(ε-caprolactone) (PCL)-based polyesterurethane (PUR) systems have been synthesized through Diels-Alder reactions by reactive extrusion. The Diels-Alder and retro-Diels-Alder reactions proved to be useful for enhancing the molecular motion of PCL-based systems, and therefore their crystallization ability, in the design of cross-linked semicrystalline polymers with one-way and two-way shape-memory properties. Successive reactions between α,ω-diol PCL (PCL(2) ), furfuryl alcohol, and methylene diphenyl 4,4'-diisocyanate straightforwardly afforded the α,ω-furfuryl PCL-based PUR systems, and subsequent Diels-Alder reactions with N,N-phenylenedimaleimide afforded the thermoreversible cycloadducts. The cross-linking density could be modulated by partially replacing PCL-diol with PCL-tetraol. Interestingly, the resulting PUR systems proved to be semicrystalline cross-linked polymers, the melting temperature of which (close to 45 °C) represented the switching temperature for their shape-memory properties. Qualitative and quantitative measurements demonstrated that these PUR systems exhibited one-way and two-way shape-memory properties depending on their cross-linking density.

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mentioning

confidence: 98%

Design of Cross‐Linked Semicrystalline Poly(ε‐caprolactone)‐Based Networks with One‐Way and Two‐Way Shape‐Memory Properties through Diels–Alder Reactions

Raquez

Vanderstappen

Meyer

et al. 2011

Chemistry A European J

117

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“…E 0 is obtained from linear regression of a linearized logarithmic format of Equation (1). In order to do this, P is calculated as: [21] P ¼ i À 0:5 n þ 0:25 ð2Þ where i denotes that this E value ranks the ith in ascending order of breakdown strength data and n is the total number of data points.…”

Section: Breakdown Behaviormentioning

confidence: 99%

“…[1][2][3][4] However, the use of XLPE as an insulating material for underground distribution cables involves many problems, including water treeing, space charge accumulation, and breakdown strength. [2][3][4][5][6] In an underground environment, the water from the soil can slowly diffuse through the insulating layers of the cables under the combined action of electric stress, forming the treelike structures, water trees, which are mainly responsible for insulation breakdown in medium-voltage (MV) cables.…”

Section: Introductionmentioning

confidence: 99%

Influence of Ethylene Ionomers on the Electrical Properties of Crosslinked Polyethylene

Huang

Wei

et al. 2006

Macro Materials & Eng

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Summary: Water treeing is a deterioration mechanism observed in the polymeric insulation of extruded cables, which can affect the service life of the transmission and distribution XLPE power cables. To improve the water‐tree resistance of XLPE, it was blended with sodium‐neutralized EAA‐Na ionomers which were formed by neutralization of EAA with NaOH. A series of XLPE/EAA‐Na ionomer blends were investigated for their electrical properties, such as water treeing, electrical breakdown strength, dielectric constant, and dissipation factor. The results strongly suggest that EAA‐Na ionomers can improve the water‐tree resistance of XLPE, and the XLPE/EAA‐Na blends retain excellent dielectric properties. Characterization of XLPE/EAA‐Na blends by using FTIR indicates that the neutralization reaction is effectively achieved. In addition, it can be found that XLPE/EAA‐Na blends are partially compatible from observing morphology observations made by SEM and, therefore, EAA‐Na ionomers can be well dispersed in the matrix.Water tree length of the XLPE/EAA‐0.5Na blends.magnified imageWater tree length of the XLPE/EAA‐0.5Na blends.

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“…Both the front and the rear electrodes were hot pressed into the plaque sample about 200 O C for 10 minutes to ensure cross-linking [3]. All degassing treatments were done in a vacuum oven, after which the samples were cooled at room temperature for 15 minutes.…”

Section: Sample Detailsmentioning

confidence: 99%

The effect of degassing on morphology and space charge

Chong

Chen

2004

Proceedings of the 2004 IEEE International Conference on Solid Dielectrics, 2004. ICSD 2004.

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It is believed that space charge buildup in cross-linked polyethylene (XLPE) insulation is one of the main cause for premature failure of underground power cables. The space charge activities in XLPE depend on many factors such as additives, material treatment, ambient temperature, insulator/electrode interface, etc. Degassing is one of the material treatment processes commonly employed in cable manufacturing to improve insulation performance. In this paper, investigation on the effect of degassing period on the morphology and space charge was carried out. Planar XLPE samples of the same composite were subjected to different degassing time. It is discovered that apart from removing volatile by-products, degassing also anneals XLPE material; changing the morphology as a result.

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On additives, morphological evolution and dielectric breakdown in low density polyethylene

Cited by 43 publications

References 47 publications

Design of Cross‐Linked Semicrystalline Poly(ε‐caprolactone)‐Based Networks with One‐Way and Two‐Way Shape‐Memory Properties through Diels–Alder Reactions

Design of Cross‐Linked Semicrystalline Poly(ε‐caprolactone)‐Based Networks with One‐Way and Two‐Way Shape‐Memory Properties through Diels–Alder Reactions

Influence of Ethylene Ionomers on the Electrical Properties of Crosslinked Polyethylene

The effect of degassing on morphology and space charge

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