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Nat Nanotechnol. 2015 Mar;10(3):277-83. doi: 10.1038/nnano.2014.248. Epub 2014 Nov 2.

Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide.

Author information

1
Department of Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden.
2
Engineering Ceramics Department, Jožef Stefan Institute, 1000 Ljubljana, Slovenia.
3
1] Department of Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden [2] Wallenberg Wood Science Centre, Royal Institute of Technology, KTH, 100 44 Stockholm, Sweden.
4
Politecnico di Torino, Corso Duca degli Abruzzi, 24 10129 Torino, Italy.
5
Max Planck Institute for Colloids and Interfaces, Potsdam-Golm Science Park, Am Mühlenberg 1, 14476 Potsdam, Germany.

Abstract

High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m(-1) K(-1), which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

PMID:
25362476
DOI:
10.1038/nnano.2014.248

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