Dielectric modelling of polymerization processes

The phenomena that accompany a polymerization reaction greatly affect the distribution and the mobility of electric charges; thus by analyzing the dielectric polarization of the system many aspects of its physical and chemical behaviour can be reconstructed. The effective extraction of the desired information depends strongly on the adequacy of the dielectric model assumed for representing the observed phenomena and on the accuracy of data treatment. In this paper the dielectric behavior of different polymerizing systems, such as epoxies, unsaturated polyesters and polyacrylates, is compared and a common modelling scheme, that gives a rationale of the changes of the dielectric parameters which is useful to monitor the evolution of the reacting systems, is proposed. Moreover, it is also shown that a simple and direct measure of the permittivity, at a suitable fixed frequency, leads to determine the conversion of the cure process of epoxy resins.