AM-FM and Loss Tangent on Polymer Sandwich

Images of a Viton®/epoxy/EPDM (left to right) sandwich. The quantitative Loss Tangent data shown in (a) clearly indicates the higher Loss Tangent of the Viton. The stiffness is measured by tracking the resonance frequency of the second mode (b), clearly resolving the difference in the elastic moduli of the Viton (Shore A 78) and the EPDM (Shore A 58). The AM-FM dissipation, related to the loss modulus is shown in (c). Finally, the Force Modulation Amplitude image (d) also shows the stiffness measured with a second technique, at much higher penetration depth, providing complementary information to the AM-FM results in (b).