Mechanical and thermal insulation properties of elium acrylic resin/cellulose nanofiber based composite aerogels

Abstract

For the first time, recyclable Elium® resin was used to dip-coat freeze-dried cellulose nanofibers (CNF) aerogel to obtain recyclable composite materials. TGA allows showing that the obtained material is less hydrophilic than the neat aerogels. The SEM analysis revealed that the CNF aerogel porosity was reduced after adding Elium® resin. It has a direct impact on the material mechanical and thermal properties. For the mechanical point of view, the results confirm that Elium® resin drastically improve the new material flexural properties. The Elium® resin, via crosslinking with the CNF aerogel, increases the composite flexural modulus and strength by at least one order of magnitude compare to the CNF aerogels. Concerning thermal properties, the degradation temperature of the Elium/CNF composite materials is about 90 °C above that of neat CNF aerogels improving the resistance of the composite material against high temperatures. The effective thermal conductivity increases as the pores are filled with the resin, inducing an increase of the solid conductivity contribution. Starting from CNF aerogels having a thermal conductivity around that of air (λ=0.025 W/(m.K)), the final composite thermal conductivity increased up to 0.1 W/(m.K). However, it can still be considered as a thermal insulator according to French regulations (λ≤ 0.1 W/m.K). Overall, this study showed how to produce materials with great potential for insulation in the building area. This new class of recyclable composite material, less hydrophilic than the CNF aerogels, have good mechanical properties, thermal stability and thermal insulation properties.