The unfilled polyester--epoxy resin system exhibits a simple TSD profile indicative of a combination of space charge and dipole relaxation processes.
g] peaks correspond to the onset of dipole relaxation in the less restricted and more restricted regions.
1], which is consistent with the dipole relaxation being associated with a cooperative relaxation of the polymer chain designated the [T.
A study with the resin modified with Modaflow, an ester copolymer dispersion agent, shows that the dipole relaxation is more ideal and the activation energy for dipole relaxation is reduced compared with that observed in the pure resin.
13) Dielectric measurements probe the dipole relaxation and reflect the chain dynamics as well as being sensitive to the mobility of ionic species within the matrix.
The omission of Modaflow moves the dipole relaxation to higher frequencies and produces a broadening of the relaxation reflected in an increase in the distribution parameter (Table 4).
4c, 4d) show clearly the space charge and dipole relaxation features.
A shift of the dipole relaxation to lower frequency is indicative of the dipole reorientation process being slowed down and the [T.