Influence of confined phase transition on the dielectric relaxation characteristics of thermochromic epoxy insulating materials

The dielectric relaxation characteristics and mechanism of thermochromic microcapsule-epoxy insulating materials are investigated. Results show that exhibit nonmonotonic characteristics, namely the time gradually increase with raised temperature between about 58℃—66℃, which cannot be depicted by conventional Arrhenius equation or Vogel-Fulcher-Tammann equation. It is proposed characteristic derived from free volume variation induced confined phase transition in microcapsules. With temperature, solid-liquid occurs limited space microcapsules, decreasing inside could restrict reorientation dipoles external electric field lead to time. epoxy specimens fitted based on model, obtaining activation energy relaxation. different microcapsule contents within same order magnitude, indicating relaxations occur verifying role characteristics.