Highly attenuative rubber modified epoxy for ultrasonic transducer backing applications

Backing materials used for ultrasonic transducer applications need to exhibit a very high attenuation coefficient and variable acoustic impedances according to the transducer bandwidth required by the application. Such materials are generally manufactured by mixing a polymer material and particles of metals or glass, which produces high acoustic impedance materials. However, the attenuation in this kind of material remains relatively low. Here, we investigate the use of two polymers blended in such a way to obtain very high attenuation coefficients. Reactive liquid rubbers are added to epoxy to obtain a heterogeneous polymer. This structure allows us to increase wave attenuation by both scattering and absorption.