BIOBASED POLYURETHANE FILLED WITH WASTE TIRE PARTICLES AS POROUS ACOUSTICAL ABSORBERS

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

Rio de Janeiro

Conferencia; Fifth International Conference on Natural Polymers, Bio-Polymers, Bio-Materials, their Composites, Nanocomposites, Blends, IPNs, Polyelectrolytes and Gels: Macro to Nano Scales (ICNP 2017 Rio),; 2017

Noise pollution is one of the worst environmental problems that continues to get worse due to fast developments of modern industries and transportation [1, 2]. One of the key solutions for reducing this problem is to improve sound absorption efficiency in houses and buildings by increasing damping capacity and optimizing pore structure of construction materials [1-3]. Flexible polyurethane foams (FPFs) offer the possibility to be useful in acoustic absorption because they are able to absorb the sound energy. When a porous material is exposed to incident sound waves, the air molecules at the surface and moving through the material within the pores are forced to vibrate and lose some of their original energy. This is because part of the energy of the air molecules is converted into heat due to thermal and viscous losses at the walls of the internal pores and tunnels within the material [4]. On the other hand, recycled rubber particles have excellent sound energy absorbency properties and their addition to a foam could contribute to develop a composite material with improved sound attenuation.In this work, hydroxylated methyl esters and glycerol were obtained, respectively, as main and by-product of the chemical modification of tung oil, following a two-step procedure. First, fatty acid methyl esters and glycerol (GLY) were obtained by means of alkaline transesterification. Then, the resultant fatty acid methyl esters were modified by hydroxylation with performic acid generated in situ. In this way, hydroxyl groups (-OH) were added to the carbon chain, resulting in hydroxylated methyl esters derived from tung oil (HMETO). Both (HMETO and GLY) are multi-functional polyols that can be used to tailor the cross-linking density and, consequently, the morphological, physical, mechanical and acoustic properties of the FPFs [5]. Thus, the aim of this work was to modify a FPF formulation based on a commercial polyether polyol and a polyisocyanate by replacing part of the former constituent by tung oil derived polyols. Furthermore, the foams were modified by the addition of waste tire particles (WTP) as filler of poor thermal and acoustic conduction. The effects of these changes on the physical, mechanical and acoustic properties of the resulting foams were evaluated.