Acoustic behaviors of polymer microspheres with tailored chain or matrix structures

Abstract

Utilizing the viscoelastic property of a polymer network to attenuate sound waves is an important technology leading to a noise-free living environment. For this purpose, three types of novel polymer microspheres have been synthesized: they are Ni-P coated acrylic polymer network, mesoporous styrenic polymer modified by deposition of Ni nanoparticles or incorporation of linear PEA chain. The sound damping performance in the audio band of 0.4-5kHz was studied by using the thick membranes made of microspheres, placed in the middle of a Perspex tube in which a speaker and a microphone were fastened at two ends. In addition, the ultrasonic wave (~35 kHz) absorption feature of the first type of microspheres was also appraised by a chemical means, namely the chemisorption extent of copper ions on a biomass adsorbent. The pertinent sound attenuation is accounted by intrinsic viscoelastic absorption, dissipative mechanism in air-polymer interface and assisted by metal scattering effect.