Soundproofing effect of polypropylene/inorganic particle composites

Two inorganic particle-filled polypropylene (PP) composites including PP/hollow glass bead (HGB) composite and PP/nanometer calcium carbonate (nano-CaCO3) composite were prepared by means of a twin-screw extruder in the present paper. The transmission loss was measured, to identify the effects of sound frequency and the filler content on the sound insulation properties of these filled systems. The results showed that the sound insulation effect of the PP/nano-CaCO3 obeyed roughly the law of mass, the transmission loss of the two composites increased nonlinearly with an increase of the filler volume fraction, and the value of the transmission loss for the PP/HGB system was higher than that of the PP/nano-CaCO3 system under the same level of sound frequency. The transmission loss increased roughly with an increase of sound frequency for the two composites except to individual sound frequency. The mechanisms of the sound insulation of these composites were discussed.