Aging behaviors of silicone rubber composite materials under outdoor environment

Abstract

We investigated the aging effect on the chemical structure of silicone rubber composite materials under outdoor environment. The variations of low molecular weight siloxanes in silicone rubber were probed by gas chromatography-mass spectrometry during the degradation process. The experimental results indicate that a series of cyclic siloxanes exist in both the virgin and aged silicone rubber samples, while the additional low molecular weight siloxanes (hexamethyl cyclotrisiloxane) only appear in the aged samples. Meanwhile, the total amounts of low molecular weight siloxanes in the aged samples are much less than those in the virgin ones. The loss of low molecular weight siloxanes is induced by the chain scission and depolymerization.

Keywords

silicone rubber / degradation / cyclic siloxane / aging behavior

References

[1] Charalampidis P, Albano M, Griffiths H, et al. Silicone Rubber Insulators for Polluted Environments Part 1: Enhanced Artificial Pollution Tests[J]. IEEE T. Dielect. El. In., 2014 740-748.

[2] Gustavsson TG, Gubanski SM, Hillborg H, et al. Aging of Silicone Rubber under ac or de Voltages in a Coastal Environment[J]. IEEE T. Dielect. El. In., 2001, 8: 1029-1039.

[3] Goudie JL, Owen MJ, Orbeck T. A Review of Possible Degradation Mechanisms of Silicone Elastomers in High voltage Insulation Application [C]. IEEE Conf. Elect. In. Dielect. Phenom., 1998, 1: 120-127.

[4] Hackam R. Outdoor hv Composite Polymeric Insulators[J]. IEEE T. Dielect. El. In., 1999, 6: 557-585.

[5] Zheng F, He CQ, Fang PF, et al. The Surface Structure of UV Exposed poly-dimethylsiloxane (PDMS) Insulator Studied by Slow Positron Beam[J]. Appl. Surf. Sci., 2013, 283: 327-331.

[6] Kim J, Chaudhury MK, Owen MJ. Hydrophobic Recovery of Polydimethylsiloxane Elastomer Exposed to Partial Electrical Discharge[J]. J. Colloid Interf. Sci., 2000, 226: 231-236.

[7] Krivda A, Hunt SM, Cash GA, et al. MALDI-TOF/MS Characterisation of LMW PDMS in High Voltage HTV Silicone Rubber Insulators[C]. IEEE Conf. Elect. In. Dielect. Phenom., 2000 703-708.

[8] Ali M, Hackam R. Recovery of Hydrophobicity of HTV Silicone Rubber after Accelerated Aging in Saline Solutions[J]. IEEE^T. Dielect. El. In., 2009, 16: 842-852.

[9] Hillborg H, Gedde UW. Hydrophobicity Changes in Silicone Rubbers[J]. IEEE^T. Dielect. El. In., 1999, 6: 703-717.

[10] Ehsani M, Borsi H, Gockenbach E. Modified Silicone Rubber for Use as High Voltage Outdoor Insulators[J]. Adv. Polym. Tech., 2005, 24: 51-61.

[11] Hillborg H, Gedde UW. Oxidative Surface Treatment of Silicone Rubber, Silicone Surface Science[M], 2012 New York: Springer. 299-318.

[12] Fritz JL, Owen MJ. Hydrophobic Recovery of Plasma-Treated Polydimethylsiloxane[J]. J. Adhesion, 1995, 54: 33-45.

[13] Tóth A, Bertóti I, Blazsó M. Oxidative Damage and Recovery of Silicone Rubber Surfaces. I. X-ray Photoelectron Spectroscopic Study[J]. J. Appli. Polym. Sci., 1994, 52: 1293-1307.

[14] Kim J, Chaudhury MK, Owen MJ, et al. The Mechanisms of Hydrophobic Recovery of Polydimethylsiloxane Elastomers Exposed to Partial Electrical Discharges[J]. J. Colloid Interf. Sci., 2001, 244: 200-207.

[15] Bodas D, Khan-Malek C. Hydrophilization and Hydrophobic Recovery of PDMS by Oxygen Plasma and Chemical Treatment-An SEM Investigation[J]. Sens. Actuators B Chem., 2007, 123: 368-373.