Ultrasonic absorption and relaxations in ABS composite polymers

We investigated ultrasonic attenuation, dynamic Youngʹs modulus, Izod impact strength, and dielectric relaxation of acrylonitrile–butadiene–styrene composite polymers (ABS) in which styrene-co-butadiene rubber particles are dispersed in styrene-co-acrylonitrile random copolymer. High ultrasonic attenuation was observed around 240 K and the intensity of attenuation increased with increasing rubber content. Temperature dependence curves of dielectric loss in the frequency range from 12 Hz to 200 kHz and temperature range from 80 to 420 K exhibited four relaxation processes designated as the α, β′, β, and γ. From the relaxation map produced for the mechanical and dielectric relaxations, the ultrasonic absorption was attributed to the β and β′ processes. It was deduced that inter-grain thermoelastic process, also contribute to the ultrasonic attenuation. Correlation was found between the ultrasonic absorption and the Izod impact strength indicating that the high impact strength of ABS is partly due to the effective absorption of impact energy through those relaxation processes.