Effect of silane‐grafting on water tree resistance of XLPE cable insulation

Water treeing is one of the main deterioration phenomena observed in the polymeric insulation of extruded crosslinked polyethylene (XLPE) cables, which can affect the service life of power cables. In this work, we investigated the effect of grafting of a silane (vinyl trimethoxysilane, VTMS) on the resistance of XLPE to water treeing. A series of water-treeing tests, the mechanical and dielectric measurements indicated that the silane-grafting could significantly improve the water tree resistance of the conventional XLPE cable insulation with little influences on its dielectric properties, e.g., the dielectric breakdown strength, dielectric constant and loss tangent, and its mechanical performance. It was found that there exists an optimum value of VTMS concentration (about 0.6 phr) corresponding to the minimum water tree length. The water tree resistance mechanism of silane-grafted XLPE was proposed on the basis of the process of silane hydrolysis and crosslinking. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

[1]  L. Dissado,et al.  A Study of the Factors Influencing Water Tree Growth , 1983, IEEE Transactions on Electrical Insulation.

[2]  L. Akcelrud,et al.  Correlations between the processing variables and morphology of crosslinked polyethylene , 2004 .

[3]  Jun Zhang,et al.  Performance evaluation of silane crosslinking of metallocene‐based polyethylene–octene elastomer , 2006 .

[4]  A. Bulinski,et al.  Polymer oxidation and water treeing , 1998 .

[5]  K. Suh,et al.  Electrical properties of chemically modified polyethylenes , 1997 .

[6]  Zhijian Jin,et al.  Investigation on water treeing behaviors of thermally aged XLPE cable insulation , 2007 .

[7]  J.-P. Crine,et al.  A water treeing model , 2005, IEEE Transactions on Dielectrics and Electrical Insulation.

[8]  T. Hjertberg,et al.  Crosslinking reactions in an unsaturated low density polyethylene , 1997 .

[9]  Robert J. Ross,et al.  Inception and propagation mechanisms of water treeing , 1998 .

[10]  Xingyi Huang,et al.  Nonisothermal crystallization behavior and nucleation of LDPE/Al nano‐ and microcomposites , 2007 .

[11]  J. Filippini,et al.  The morphology and behavior of the water tree , 1993 .

[12]  Xingyi Huang,et al.  Influence of Ethylene Ionomers on the Electrical Properties of Crosslinked Polyethylene , 2006 .

[13]  Xingyi Huang,et al.  Thermal, mechanical, and dielectric behaviors of crosslinked linear low density polyethylene/polyolefin elastomers blends , 2007 .

[14]  P. J. Phillips,et al.  Peroxide crosslinking of linear low‐density polyethylenes with homogeneous distribution of short chain branching , 1995 .

[15]  J.-P. Crine,et al.  Electrical, chemical and mechanical processes in water treeing , 1998 .

[16]  Zensuke Iwata,et al.  Investigations of Water Effects on Degradation of Crosslinked Polyethylene Insulated Conductors , 1972 .

[17]  Jun-Ho Lee,et al.  Water tree retardation and electrical properties of EVA blended XLPE , 1992, [1992] Proceedings of the 4th International Conference on Conduction and Breakdown in Solid Dielectrics.

[18]  Xingyi Huang,et al.  Atomic force microscopy analysis of morphology of low density polyethylene influenced by Al nano‐ and microparticles , 2008 .

[19]  Yeong-Tarng Shieh,et al.  Thermal fractionation and crystallization enhancement of silane‐grafted water‐crosslinked low‐density polyethylene , 2001 .

[20]  N. Yoshimura,et al.  The influence of crystalline morphology on the growth of water trees in PE , 1996 .