Carbon fibres have fundamentally different electric properties from the common thermoset resins used in composites. Carbon fibres are quite conductive whereas thermoset resins are good insulation materials, so any attempt to measure the dielectric properties of the resin in a carbon-fibre composite part is technically not feasible. It's not a matter of using advanced dielectric analysis tools because it's the physics that cannot be beaten. The existence of the carbon-fibres just short-circuit any electric field unless someone manages to separate (at least locally) the resin from the carbon-fibres.
Furthremore, there are in the literature some studies in which the electrical resistance of the carbon-fibre laminate is being measured for process monitoring. Evidently, what is being measured is the electrical resistance of the carbon fibre preform between the electrodes, which, in any case, is not relevant for monitoring the state of the resin.
At Synthesites, we have developed special sensors (the CF series) which separates locally a very small amount of resin which is used to measure its dielectric properties, either only arrival or also the full range of curing.
