Pine (P. pinaster) and quebracho (S. lorentzii) tannin-based foams as green acoustic absorbers
Résumé
Open cells structure tannin-furanic foams prepared using two different types of tannins have been shown to give good sound absorption/acoustic insulation characteristics at medium and high frequencies (1000-4000 Hz) with coefficients of acoustic absorption of 0.85-0.97. Their acoustic absorption coefficient was lower 0.40-0.60 at lower frequencies (250-500 Hz). Compared with commercial foams, tannin-furanic foams have the same typical behavior of light porous materials. The more open-cell is the material the better is its sound absorption. Thicker samples absorb better at medium frequencies for all types of porous material tested.