Empirical modelling of the acoustic behavior of sheep wool/soy protein biocomposites

Abstract

Many synthetic materials used as sound absorbers in building industry require many resources in their manufacturing process; therefore, searching for sustainable and eco-friendly alternatives, such as biocomposites with natural fibers embedded in a polymer matrix, is a promising option. In this work, soy protein was combined with 10, 15 and 20 wt % sheep wool by freeze-drying in order to develop porous biocomposites for sound absorption applications. Sound absorption coefficients at normal incidence were close to 1 at medium and high frequencies and, thus, competitive values were yielded. Additionally, airflow resistivity values were determined, obtaining values above 5 kPa s m−2, adequate values for building materials. Furthermore, an empirical model was developed to predict the sound absorption behavior of the biocomposites. Comparison of the estimated values for sound absorption with their experimental counterparts showed good agreement and provided a practical prediction tool to facilitate the design of acoustic solutions.