Polymer evaluation by using the thickness longitudinal and shear vibrations of piezoelectric ceramics: application to the monitoring of thermosetting resins' polymerization

This work deals with the analysis of the electric impedance of piezoelectric ceramics embedded in viscoelastic materials. By using a theoretical approach, we show that this parameter is a function of the viscoelastic properties of the medium surrounding the piezoelectric ceramic. Then a method for extracting the viscoelastic properties of the outside medium from the piezoelectric ceramic electric impedance is described. Finally, this technique is used for monitoring the polymerization of epoxy-amine resins.