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Description
This work investigates analytical models for the thermoacoustic performance of sustainable fibrous materials. Among the analytical formulations considered, porosity is identified as the key parameter linking the semi-phenomenological acoustic formulations of the Johnson-Champoux-Allard (JCA) model to the effective thermal conductivity k_eff modelling. The primary objective is to propose an integrated theoretical framework to balance thermal and acoustic insulation performance in sustainable insulating systems. The methodology consists of correlating the transport parameters of the JCA model with analytical formulations of the effective thermal conductivity, followed by validation through experimental measurements conducted on Posidonia oceanica fibres. The results indicate that increasing porosity enhances thermal insulation, reducing the effective thermal conductivity to values as low as 0.03 W·m⁻¹·K⁻¹. However, this increase leads to a pronounced decrease in the average sound absorption coefficient, which drops from 0.6 to 0.1. Based on this initial analysis, a first attempt at establishing a multifunctional correlation is proposed, identifying porosity as a governing parameter in the maximization of thermal efficiency, which is, in turn, intrinsically linked to acoustic energy dissipation through viscous mechanisms. Overall, this study represents an initial step toward integrating a thermoacoustic perspective into the development of sustainable bio-based materials.