Mechanical characterization of cellulose aerogels

Abstract

Due to dwindling fossil resources, biobased cellulose aerogels, whose three-dimensionally structured networks are characterized by nanoscale fibrils, have been of particular interest in recent years. They can be produced by bringing the polymer chains into solution and subsequent regeneration processes and offer the low density and thermal conductivity typical of aerogels. Their bulk properties depend on their nano and microstructure, which is influenced by their manufacturing process [1]. For practical applications of cellulose aerogels, insights into their elastic and inelastic mechanical properties are desired. To the best of our knowledge, the reports in the literature merely describe the stress-strain curves under monotonic uniaxial compressive loading [2] without exploring the inelastic features. This work aims at extending the state of the art knowhow on mechanical characterization of cellulose aerogels within this context. For this purpose, cellulose aerogels having different cellulose concentrations synthesized using ZnCl2 as solvent, salt hydrate routine [3] were subjected to an intensive mechanical characterization. This included quasi static compression and tensile tests, which for the first time allow a detailed characterization of their strain dependent elastic as well as inelastic properties. Furthermore, the results will be illustrated in the context of computational design of their microstructure with already established approaches [4] to better investigate structure property relations in the future. REFERENCES [1] Rege A, Schestakow M, Karadagli I, Ratke L, Itskov M, Micro mechanical modelling of cellulose aerogels from molten salt hydrates, Soft Matter. 12(34),7079-88, 2016. [2] Buchtova N, Pradille C, Bouvard JL, Budtova T, Mechanical properties of cellulose aerogels and cryogels, Soft Matter, 15, 7901-8, 2019. [3] Schestakow M, Karadagli I, Ratke L, Cellulose aerogels prepared from an aqueous zinc chloride salt hydrate melt, Carbohydrate Polymers, 137, 642-9, 2016. [4] Aney S, Rege A, The effect of pore sizes on the elastic behaviour of open porous cellular materials, Mathematics and Mechanics of Solids, 0(0), 2022.