Organosilica foams are commonly formed by a multistep process involving hydrolysis and condensation of organosilanes followed by solvent exchange and e.g. supercritical CO2 drying. Here, we propose a straightforward route to synthesize lightweight hybrid foams from aqueous dispersions of a surface-active aminosilane (AS) and TEMPO-oxidized cellulose nanofibrils (TCNFs). Air bubbles were introduced in the TCNF/AS dispersion by mechanical blending, and the foam was solidified by oven-drying. Evaporative drying at mild temperature (60 °C) resulted in dry foams with low densities (25-50 kg/m3), high porosities (96-99 %) and macropores of 150-300 μm in diameter. The foaming and foam stabilization were successful for a pH range of 10.4–10.8 for foams containing 55-65 wt% of organosilica in the dry state.<br/>The mechanisms of stabilization of the wet and solid foams will be discussed, and an overview of the properties of the thus-produced solid foams will be given for target applications.

Lightweight foams of amine-rich organosilica and cellulose nanofibrils: Processing, properties and potential applications

2019 Spring National Meeting

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