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A scalable high-porosity wood for sound absorption and thermal insulation


The search for more-sustainable materials has motivated research on lightweight, porous structures for thermal insulation and noise reduction, such as for construction and cold-chain transportation. Wood, known as one of the most renewable materials on Earth, has been widely and long used in construction for its high strength/weight ratio, wide abundance, low cost and relative sustainability. However, natural wood is much less effective at reducing noise or preventing heat loss than conventional petroleum- and mineral-based porous structures (for example, expanded polystyrene foam and mineral wool). Here we report the extraordinary noise-reduction and thermal-insulation capabilities of a scalable, high-porosity wood structure, ‘insulwood’, fabricated by removing lignin and hemicelluloses from natural wood using a rapid (~1 h) high-temperature process followed by low-cost ambient drying. Insulwood demonstrates a high porosity of ~0.93, a high noise-reduction coefficient of 0.37 at a frequency range of 250–3,000 Hz (for 10-mm-thick wood), a low radial thermal conductivity of 0.038 W m–1 K–1 and a high compressive strength of ~1.5 MPa at 60% strain. Furthermore, this new wood-based material can be rapidly processed into a vacuum insulation panel (~0.01 W m–1 K–1) for thermal insulation applications with limited space (for example, refrigerators, cold-chain transportation and older buildings). The material is unique in its combination of renewable source materials, high porosity, high sound absorption, low thermal conductivity and high mechanical robustness, as well as in its efficient, cost-effective and scalable manufacturing. These attributes make insulwood promising as a sustainable construction material for improved noise and thermal regulation.

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Fig. 1: The fabrication and thermal performance of insulwood and insulwood-based VIPs.
Fig. 2: Morphology and structure of the natural wood starting material and insulwood.
Fig. 3: Sound absorption of the insulwood.
Fig. 4: Thermal and mechanical properties of insulwood.

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Data availability

The data that support the findings of this study are available within this article and its Supplementary Information. Source data are provided with this paper.


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L.H., X.Z., A.G., J.D., D.S. and J.Y.Z. acknowledge the support from the Department of Energy’s Building Technologies Office (BTO) through the Small Business Innovation Research Program under Contract DE-SC0018820. L.H., X.Z., A.P.S., A.G., J.D., J.K. and J.Y.Z. acknowledge the support from the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Building Technologies Office (BTO), Award Number DE-EE0009702. X.Z. also acknowledges the use and support of the Maryland NanoCenter and its AIMLab.

Author information

Authors and Affiliations



L.H. and X.Z. conceived the idea and designed the experiments. X.Z. and Y.L. contributed to the insulwood fabrication and characterization. Y.M. contributed wide-angle X-ray scattering measurement. A.P.S., S.J., H.X., Z.L., J.L. and B.C.C. contributed to collection of the SEM and digital images. J.D. and J.Y.Z. contributed to the large-scale sample fabrication. L.Z., A.Y. and M.Y. contributed to the sound-absorption measurement and simulation. X.Z. contributed to thermal measurements and simulations. G.S.C. and E.Q.W. contributed to characterization of moisture absorption and flammability. S.H. provided characterization via FTIR. A.O.D. validated the thermal measurements. D.S. and A.G. provided useful suggestions for raw woods selection and insulwood fabrication. J.K. contributed to the design of the VIP fiber core, provided useful suggestions for VIP fabrication, and performed thermal performance analysis. X.Z. and L.H. collaboratively analyzed the data and wrote the manuscript. All authors commented on the final manuscript.

Corresponding author

Correspondence to Liangbing Hu.

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Competing interests

The authors declare the following competing interests: Dr. Liangbing Hu co-founded a company, InventWood, to commercialize wood-based thermal/acoustic insulation materials. However, all results reported herein were performed under federal sponsorship. The remaining authors declare no competing interests.

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Nature Sustainability thanks Kai Zhang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–30, Table 1, Notes 1–6 and references.

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Source data

Source Data Fig. 2g

FTIR spectra of the natural wood and insulwood.

Source Data Fig. 3b

The sound-absorption coefficient of the natural wood and insulwood as a function of frequency.

Source Data Fig. 4e

Stress–strain curves of the insulwood under compression along the radial direction.

Source Data Fig. 4h

Comparison of the outgassing rate of the insulwood and EPS.

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Zhao, X., Liu, Y., Zhao, L. et al. A scalable high-porosity wood for sound absorption and thermal insulation. Nat Sustain 6, 306–315 (2023).

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