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 showes 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).

A Novel and Facile Nanoclay Aerogel Masterbatch toward Exfoliated Polymer‐Clay Nanocomposites through a Melt‐Mixing Process

“…e lamellar structures and voids inside the nanoclay aerogel structures were created by the sublimation of ice. Similar results were reported in many studies based on preparing polymer/clay aerogels with various types of polymers [42,[51][52][53][54][55][56][57][58]. e denser lamellar morphology was observed with the increase of the nanoclay loadings due to the limitation of the expanded space between the adjacent lamellar at a high nanoclay content.…”

Facile preparation of attapulgite‐based aerogels with excellent flame retardancy and better thermal insulation properties

“…The development of a nanonetwork system and hence the integrity of the ATP‐based aerogel are due mainly to the synergistic effect among ATP, MACCN, and PVA. The negative charges on the surfaces both of ATP and MACCN do not allow them to bond with each other, so a special intermediate medium with double functionalities should be introduced into the mixture, and PVA was considered to be the most suitable material to play this role . Based on this concept, PVA is first adsorbed onto the surface of ATP, which leads to a decrease in surface charge and provides proper conditions.…”

“…The negative charges on the surfaces both of ATP and MACCN do not allow them to bond with each other, so a special intermediate medium with double functionalities should be introduced into the mixture, and PVA was considered to be the most suitable material to play this role. 30 Based on this concept, PVA is first adsorbed onto the surface of ATP, which leads to a decrease in surface charge and provides proper conditions. Then MACCN can be adsorbed on the outer surface of ATP crystals through hydrogen bonding, which is provided by the ATP and PVA, and the bridging connection between neighboring ATP crystals is thus generated.…”

Evaluation of crosslinking and surface coating on the moisture resistance of freeze‐dried clay aerogel

“…For cross‐linked aerogel, the number of bridges decreases, and bridges become thinner (Fig. b–d).The reason attributed to this is that the addition of GPTMS weakens the interaction between PVA and clay, and thus the hybrid of PVA/clay in ice front is easy to rearrange during ice growth, hindering the formation of bridges . In comparison, the surface‐coated aerogel preserves the original structure of PVA/clay aerogel (Fig.…”

“…The second stage starts around 350°C, consistent with the decomposition of GPTMS network in cross‐linked aerogel. This significant improvement of surface‐coated aerogel in thermal stability is ascribed to the formation of thermal stable silica layer on the surface of laminas and bridges, hindering the diffusion of volatile decomposition products within aerogel .…”