Generic representation of cure monitoring data using the time-temperature-transformation (TTT) diagram: Equivalence between dielectric and ultrasonic properties

Ultrasonic and dielectric cure monitoring techniques have been used to characterize the cure of a typical epoxy-amine adhesive over a range of different cure conditions. The time-temperature-transformation (TTT) diagram has been used as a generic representation of the data to facilitate comparison between the two techniques. This paper discusses the similarities between the evolving dielectric and ultrasonic properties of the thermoset by investigating the dielectric and ultrasonic loss tangents and the relaxation phenomena observed in each case. Both techniques are shown to be sensitive to variations in cure temperature although for a fixed test frequency the dielectric technique seems to be more sensitive to changes in the early stages of cure whereas at the same frequency the ultrasonic technique appears to be more sensitive to the final stages of the process.