Valorized sheep wool biocomposites towards a more sustainable building sector: Thermal insulation, sound absorption, and resistance against insects

Abstract

In the search for sustainable and environmentally friendly alternatives for building insulation materials, biocomposites of sheep wool embedded in a polymer matrix were prepared by freeze-drying, combining soy protein with 7, 10, 15 and 20 wt % sheep wool. In addition, in order to protect these biocomposites against insects, coffee grounds were incorporated into the formulation. Thermal conductivity characterization revealed values in the order of other natural insulating materials. Additionally, coefficients of absorption at normal incidence, with values up to 0.96, showed a competitive performance of the biocomposites, in the same line of the samples without coffee grounds. Furthermore, the test of resistance against insects, with 2B classification according to ISO 3998, showed a good protection against keratophagous insects, especially against carpet beetle (Anthrenus flavipies). Consequently, biocomposites with an entirely renewable and eco-friendly composition, which valorize biowaste from different sources, were found to be functional as thermal and acoustic insulators towards more sustainable materials in the building sector. © 2025 The Authors