• Andritsch, Thomas
• Salter, Daniel J.
• Saeedi, Istebreq A.
• Vaughan, Alun S.

Abstract

<p>Epoxy resins are used as the base insulating material in many electrical applications, including cast resin transformers, bushings and cable terminations. The performance of the resin-based insulation governs the efficiency of these applications. To understand the factors that determine the different properties of epoxy resin insulating materials, in this work, we studied the thermal and electrical properties of amine and anhydride cured epoxy resin systems. The glass transition temperature Tg, permittivity and breakdown strength of three resin systems were investigated. The results of differential scanning calorimetry indicated that the Tg of the tested system is related to the free volume in the system, which is affected by the degree of cross linking. The extent of reactions between the resin and the hardener (or the crosslinking) is ascribed to the reaction mechanisms between the active group of the hardener and the epoxide groups of the resin. Dielectric spectroscopy revealed a standard beta relaxation in the imaginary permittivity of all systems. The strength of the beta relaxation is related to the formation of hydroxyl groups and the local structure around the crosslinking which may constrain the movement of the -OH groups. This research provides insights concerning the relations between the curing mechanisms and the thermal and electrical properties; this, consequently, represents a potential mean of tailoring the overall performance of epoxy resin systems to suit particular applications.</p>

Topics

• impedance spectroscopy
• glass
• glass
• strength
• thermogravimetry
• glass transition temperature
• differential scanning calorimetry
• resin
• amine
• curing