Biobased porous acoustical absorber made from polyurethane and waste tires particles.

G. SOTO; N. VIACHETTI; N. E. MARCOVICH; F. IASI; M. A. MOSIEWICKI; A. ARMAS

Buenos Aires

Congreso; 22nd International Congress on Acoustics. ICA2016; 2016

The production of flexible polyurethane foams (FPU) incorporating bio/recycled raw materials is aninteresting alternative to conventional acoustic absorbent materials. In this sense, bio-based polyols like glycerol (GLY) orhydroxylated methyl esters derived from tung oil (HMETO) as multifunctional polyols, and waste tires particles (WTP) asfillers of low thermal conductivity and capability for acoustical absorption, are prospective feedstocks for FPU preparation.In this work, FPU were prepared by adding different amounts of these components to a formulation based on acommercial polyether polyol. Results of scanning electron microscopy (SEM) analysis, compression tests and normalsound absorption coefficient measurements at different frequencies are presented and discussed. The addition of WTPor GLY to the commercial formulation enhanced both the modulus and yield stress of the obtained FPU and in all thecases, a high recovery of the strain (>90%) applied in compression tests was attained after 24 hours. On the other hand,the obtained FPU presented good performance as acoustic absorbers from 500 Hz, with NRC and SAA values near andabove 50%. Moreover, the absorption coefficient reaches high values mostly at the highest evaluated frequencies (~62-89% at 2000 Hz and ~70-91% at 5000 Hz), for 30 mm thickness samples. SEM micrographs revealed that the obtainedfoams present a combination of open and closed cell structures and both, the modifiers and particles, tend to decreasethe cell size. Based on morphological analysis and acoustical and mechanical performance, the results show that thesenew kind of materials could be innovative sound absorbers, cheaper and environmentally more convenient in comparisonwith other available materials.