Forest-Based Biodegradable Foam for Thermal Insulation

Foams are versatile and commercially attractive materials widely used in numerous applications, from regular furniture and automotive parts to complex sensors and biomedical devices. However, most of the foams currently available in the market are fossil-based, non-biodegradable, and rarely reused or recycled, representing a significant share of the non-treated residues that end up in landfills and oceans that contribute to the continuous degradation of our ecosystems[i],[ii].
Accordingly, we present the use of cost-effective micro-fibrillated cellulose (MFC) produced from unbleached eucalyptus industrial pulp fibers as a bio-based raw material to design a novel sustainable and high-performance insulation foam as an alternative to the fossil-based (polystyrene or polyurethane) foams applied in the building construction. MFCs perform similarly to other cellulosic materials, such as bacterial cellulose or nano-fibrillated cellulose, and present valuable chemical and mechanical properties, which can act alone or in combination with other natural and renewable materials to form strong networks. Moreover, plant-based unbleached MFCs are widely available, do not require any extra chemicals during their manufacturing, present a significantly lower production energy consumption when compared to other materials with parallel performances, and their production line can be easily adaptable to any industrial pulp mills.
Here, unbleached MFCs were combined with other biomaterials to form an insulating and humidity-resistant crosslinked aerogel produced by freeze-drying. Our foams present low density (30kg/m³), high porosity (53%), a compression force of 10N under 25% of strain, thermal stability up to 210 degree Celsius, thermal conductivity of 44 mW/m.K (~ 34 and 36 mW/m.K for polyurethane and polystyrene foams, respectively) and 95% compostable in 12 weeks (ISO 23517:2021).
Overall, this tailored design foam represents a commercially viable alternative to fossil-based products, with excellent mechanical, thermal, and insulation properties aligned with the requirements of the packaging/building construction industry. Further, and most importantly, it shows a sustainable profile from its conception, using responsible, renewable, and abundant raw materials, to its end-of-life, due to its biodegradable/compostable behavior, essential for the continuous development of a sustainable and profitable circular economy where our ecosystems remain undamaged, and the future of the next generations is secured.


[i] Raquel Silva, Ana Barros-Timmons, Paula Quinteiro, Life cycle assessment of fossil- and bio-based polyurethane foams: a review, Journal of Cleaner Production, Volume 430, 2023, 139697, ISSN 959-6526, https://doi.org/10.1016/j.jclepro.2023.139697.

[ii] https://europur.org/flexible-pu-foam/sustainability/