Development of facture free clay-based aerogel: Formulation and architectural mechanisms

Abstract

Clay aerogel could potentially be ideal insulation materials for many industrial sectors because of its natural resource, green and low cost production. However, there is a dilemma between thermal conductivity and integrity, which are also highly related to density and microstructure. These could be manipulated through formulation compositions and processing parameters. This paper employs cellulose nanowhisker (CNW) as the reinforcement to develop novel 3-component systems of aerogel by exploring optimum formulation and architectural microstructure systems. The results show that fracture free clay aerogel can be developed with solid content less than 4 wt%, enabling optimum thermal insulation performance of 0.034 W/mK; optimum micro-network and hence much more enhanced bonding systems can be built with strategical interactions within and between clay platelets, PVA and CNW; and an architecture of ‘CNW–clay (mechanically) + CNW–PVA (chemically) + CNW–clay’ 3-component clay aerogels could be established, achieving excellent mechanical property (e.g. compressive strength and shape recovery).