Dynamic Dielectric Analysis for Nondestructive Cure Monitoring and Process Control

A rapid, convenient and accurate experimental technique has been devel oped for evaluating continuously, in-situ and on-line, the cure process of thermoset resins. The technique is based on the development of a small inert sensor which is used to make continuous, uninterrupted measurements of the frequency dependence of the resin's im pedance in the Hz to 10 MHz region throughout the entire cure process. This technique is used to monitor the viscosity and the rate of cure of unsaturated polyester and epoxy resins both in a laboratory and a production environment. In particular, the effect of resin thickness and initiator concentration are discussed.