Open Access

ARTICLE

Structure-Thermal Conductivity Tentative Correlation for Hybrid Aerogels Based on Nanofibrillated Cellulose-Mesoporous Silica Nanocomposite

Dounia Bendahou^1,2, Abdelkader Bendahou¹, Bastien Seantier¹, Bénédicte Lebeau³, Yves Grohens^1,*, Hamid Kaddami^2,*

1 University of Southern Brittany, Dupuy de Lôme Research Institute, FRE-CNRS 3744, BP 92116, 56321 Lorient Cedex, France
2 Cadi Ayyad University, Faculty of Sciences and Technologies, Avenue Abdelkrim Elkhattabi, B.P. 549, Marrakech, Morocco
3 University of Upper Alsace, Institute of Materials Science of Mulhouse (IS2M), 68057 Mulhouse Cedex, France

*Corresponding authors: ;

Journal of Renewable Materials 2018, 6(3), 299-313. https://doi.org/10.7569/JRM.2017.634185

Abstract

Hybrid aerogels have been prepared by freeze-drying technique after mixing water dispersions of cellulose microfibers or cellulose nanofibers and silica (SiO2) of type SBA-15 (2D-hexagonal). The prepared composites were characterized by different analysis techniques such as SEM, hot-filament, DMA, etc. These composites are compared to those previously prepared using nanozeolites (NZs) as mineral charge. The morphology studied by SEM indicated that both systems have different structures, i.e., individual fibers for cellulose microfibers WP-based aerogels and films for nanofibrillated cellulose NFC-based ones.... These differences seem to be driven by the charge of the particles, their aspect ratio and concentrations. These hybrid materials exhibit tunable thermal conductivity and mechanical properties. The thermal conductivity values range between ~18 to 28 mW. m–1. K–1and confirm the superinsulation ability of these fibrous aerogels. Synergism on the thermal insulation properties and mechanical properties was shown by adjunction of mineral particles to both cellulose-based aerogels by reaching pore size lower than 100 nm. It significantly reduces the thermal conductivity of the hybrid aerogels as predicted by Knudsen et al. Furthermore, the addition of mineral fillers to aerogels based on cellulose microfibers induced a significant increase in stiffness.

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