Ultrasonic and thermal cure monitor of an epoxy resin

The ultrasonic cure monitor technique was investigated to assess the mechanical property development during the cure of an epoxy resin system, EPON 815/V 140. The ultrasonic cure monitor is a nondestructive technique which can be adapted to on-line process monitor and control. The modulus extent is derived and presented as a characterization parameter similar to the degree of cure in thermal cure characterization. The modulus extent and degree of cure histories for five isothermal cures are compared. Results have shown that the degree of cure does not accurately reflect the mechanical property development during cure. Significant changes in the modulus extent occur during the later stages of cure when the degree of cure is fully developed.