Change in the electrical properties due to modification of the epoxy network structure using reactive diluents

There is a wide range of commercial applications that utilize epoxy resin as a main insulation material. Recent studies revealed that changing the molecular structure in epoxy/anhydride systems, by the introduction of a reactive diluent, can significantly improve the electrical properties. This research is of interest for high voltage applications, because the introduction of these reactive modifiers may provide a means of tailoring the dielectric properties of epoxy resins, such as permittivity and conductivity. The results reported in this work reveal that the addition of a reactive diluents greatly affects the glass transition temperature, T
_g
, the permittivity, the DC conductivity and the breakdown strength. This can be explained through the reactive diluent leading to a significant modification of the epoxy network, whereby changed free volume caused by the presence of small branches alters the properties of the system. Therefore, the concept described, in principle, may be used to varying material properties in a controlled manner to tailor the properties of epoxy resins.