Gel Point Determination in Curing Polydimethylsiloxane Polymer Networks by Longitudinal Ultrasonic Waves

Abstract

The formation of well characterized poly-dimethylsiloxane networks has been studied by means of an acoustic interferometer. The hydrosilation reaction used to form these networks was followed by infra red spectroscopy. The relative changes in velocity of the ultrasonic longitudinal waves propagating through the system are found to be very sensitive to gelation and to the density of crosslinks. Due to our simultaneous kinetic and ultrasonic studies it was possible to relate the changes in acoustic properties of the curing system directly to the cure state.