Acoustic & Mechanical Properties of Neoprene Rubber for Encapsulation of Underwater Transducers

Acoustical and mechanical properties of specially designed Neoprene rubber compounds were investigated. Three different hardness materials were developed with varied carbon black loading. Sound velocity and density of materials were measured. Acoustic impedance of the materials were evaluated and compared with the acoustic impedance of sea water. Insertion loss and echo reduction of the materials were measured in the frequency range 15 kHz to 85 kHz at room temperature. Insertion loss was less than 2 dB and echo reduction was more than 10 dB through out the frequency range which is suitable for underwater transducer encapsulation material.
Mechanical properties like tensile strength, elongation at break and hardness etc. were investigated which is important for encapsulation materials to withstand hydrostatic or hydrodynamic pressure exerted on it. Materials resistance to hot air ageing and sea water were also conducted in the present study.