Polyurethane/poly(vinylidene fluoride)/MWCNT composite foam for broadband airborne sound absorption

Abstract

ABSTRACTA polyurethane/poly(vinylidene fluoride)/multi‐walled carbon nanotubes (PU/PVDF/MWCNT) (83/15/2) composite foam was designed and fabricated. The foam exhibited high airborne sound absorption performance in a wide‐frequency range. The sound absorption coefficient reached the value of 0.85 at 1 kHz, which is a significant improvement over PU foam. It was found that PVDF formed a separate immiscible phase and part of it was crystallized in a polar phase in the PU scaffold in the PU/PVDF/MWCNT composite, which could benefit the sound absorption performance by introducing interfacial damping and local piezoelectric damping effects. The introduction of the conductive MWCNT filament in the composite foam further improved sound absorption, possibly by facilitating the dissipation of the electrical charges generated from local piezoelectric effect and enhancing both the interfacial damping effect and local piezoelectric damping effect. With PU as the main ingredient, the fabrication scalability of the foam can be improved with significantly reduced material and production cost in comparison with PVDF foam. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47868.