Studies on the sound absorption properties of wood-based pulp fibre foams

Acoustic behaviour of wood fibres depends on material properties on different hierarchical structural levels, including molecular, microscopic, and macroscopic. In this paper, we present comprehensive studies on the effect of the hierarchical structure of wood pulp fibres on acoustical properties. In the molecular level,
structural polymers of wood and their arrangement in the cell wall are crucial in determining the material properties of the fibres. In the microscopic level, wood fibres are characterised by an irregular morphology and present average fibre lengths and widths ranging from 0.4 – 6 mm and 10 – 50 µm, respectively. In the
macroscopic level, the porous structure of a 3D-fibre network formed by means of foam-forming technique depends on the raw fibres as well as on the foam forming procedure used. The studied pulp fibre foams achieve comparable sound absorption properties to those of conventional synthetic porous materials. Increasing use of wood based materials in buildings contribute to reduce CO2 from the atmosphere by binding CO2 into the building structure for decades.