Material enthalpy-the classifier of curing of dielectrics containing epoxy resins

Monitoring of the properties and applicability of high-voltage insulating systems containing epoxy resins require knowledge of curing degree of these resins. This curing degree is considered to be the key parameter for quality of materials used for these systems. Application of differential thermal analysis (DTA) for evaluation of curing degree of three-component composite materials (glass fabric, reconstructed mica, epoxy resin) is presented in the article. Used analysis enables to observe characteristic structural parameter-the concentration of reactive particles in organic component of this material. In our investigation, concept of curing reactions courses was obtained as well as the details for determination of optimal curing time of material. These conclusions have been confronted with the other methods such as thermomechanical analysis (TMA) or dissipation factor and permitivity determination. Based upon these results it is obvious, that the conclusions correspond to one another.