Dielectric non-destructive testing approach to cure monitoring of adhesives and composites

In the fabrication of many composite and adhesively bonded structures it is desirable to determine the extent to which complete cure is achieved. This review briefly discusses the fundamental issues which are involved in the monitoring of the cure process in thermoset resins. The application of the dielectric method is described as a non-destructive probe for the monitor of the cure process in thermoset resin systems. The principles of the technique are illustrated with reference to a simple epoxy-amine structural adhesive. Possible correlations between the changes in the dielectric properties with other physical property changes of a resin, e.g. viscosity, during cure are discussed.