Diatomaceous Earth/Polyvinylidene Fluoride Piezoelectric Composite Foam for Enhancing Sound Absorption Performance

Noise has become a major potential problem in modern society, with a profound impact on human health. There is an urgent need to develop more effective sound-absorbing materials to control noise. In this study, composite foams were prepared by the sacrificial template method combined with non-solvent-induced phase separation using polyvinylidene fluoride (PVDF) as matrix and diatomaceous earth (DE) as filler. The result shows the addition of DE can act as a crystallization site to induce the formation of β phase in the PVDF matrix, thus enhancing the piezoelectricity of the foam. Due to the local piezoelectric effect of PVDF promoted by DE and the high porosity of DE itself, the sound absorption performance of DE/PVDF composite foam was better than that of pure PVDF foam. When the DE was 5 wt%, the noise reduction coefficient of DE/PVDF-2 composite foam was 50% higher than that of pure PVDF foam, and the average sound absorption coefficient (500–6400 Hz) was 38.5% higher. This work successfully prepared a moistureproof, flame-retardant, compression-resistant, and lightweight PVDF composite sound-absorbing foam, which is expected to be a commercial sound-absorbing material.

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