Monitoring the moduli of polymers with ultrasound

Abstract

Two ultrasonic methods are presented for the measurement and monitoring of the elastic moduli of polymers and other liquids undergoing solidification. The methods are thought to be most sensitive to the buildup of the real component of the modulus of rigidity of the material. Ultrasonic traveling waves are used to interrogate a boundary between the solid body transmitting the wave and the sample under test. Data on epoxy resins are given. During the hardening process, the measured modulus includes contributions from viscoelastic and glass transition effects which are not separated from the total modulus by the measurement methods.