Influence of interface/interphase on the dielectric properties of composites

摘要

Thermally stimulated current spectroscopy (TSC) has been applied to the study of interfaces/interphases in composites. Three DGEBA-DDA matrix model samples have been considered: matrix, matrix plus elastomer-coated glass beads, and matrix plus silane-treated glass beads. Below room temperature, the gamma and beta relaxations have been observed together with the mode associated with the glass transition of the elastomeric interphase that only represents less than 1% in weight of the composite. Above room temperature, a complex TSC alpha peak has been found with the same characteristics regardless of the nature of the interface/interphase in composites. However, the analysis of the fine structure of the alpha mode shows the existence of a compensation phenomenon characteristic of the matrix-filler interface/interphase. Surface treatment by silane decreases the number of accessible sites while the elastomeric coating increases the number of accessible configurations.