Sound absorption behavior of multiporous hollow polymer micro-spheres

Multiporous polymer micro-spheres with interconnected cavities have been prepared by a simple modified emulsion polymerization of acrylate monomers and polymerizable emulsifier. The morphology of micro-spheres was characterized by a scanning electron micrographs (SEM) and the sound absorption behavior of the micro-spheres materials was tested in an impedance tube. It is shown that the porous structures and low density allow the micro-spheres to embrace more diversified modes to attenuate sound wave energy. Besides the sound energy being dissipated at the interface of the air and the solid structures of micro-spheres, high absorption coefficient are given rise to by the vibration of the micro-spheres at the resonant frequencies.