On the Dielectric Relaxation Characteristics of Epoxy Resin Cured by Co-anhydride Hardener

Anhydride cured epoxy resin is often used as an insulating material for power electronic equipment, and its common anhydride curing agents include Hexahydrophthalic anhydride (HHPA) molecule and Methylhexahydrophthalic Anhydride (MHHPA) molecule. For HHPA and MHHPA, to investigate their difference and the influence mechanism in dielectric relaxation properties, the mixed curing agents were made to observe the evolution of the dielectric relaxation process, the relative permittivity (ε’) and the dielectric loss tangent (tanδ). The molecular dynamics (MD) simulation was run to study the influence mechanism of dielectric relaxation properties from the view of the cross-linked network structure. The results indicated that the ε’ and the tanδ increase on the whole with the increase of the content of HHPA. Analysis of the dielectric relaxation process and the cross-linked network structural parameters allowed some insight into dipole movement and the relationship between dielectric properties and the cross-linked network.