Temperature-Responsive Clay Aerogel−Polymer Composites

Abstract

Polymer composites reinforced by hydrophilic clay aerogels were produced and found to possess interpenetrating cocontinuous structures, not the exfoliated structure often observed in clay nanocomposites. An efficient process for producing these clay aerogels was recently reported; in-situ polymerization of N-isopropylacrylamide within the clay aerogels was readily accomplished. The resulting composites have low densities, are stable, and exhibit a new synergistic effect of interpenetrating organic−inorganic phases in which the organic polymer prevents loss of aerogel structure in water by encapsulation, while the inorganic filler increases the structural integrity of the polymer. The composites undergo phase transition and show LCST behavior similar to unmodified poly(N-isopropylacrylamide) despite the presence of reinforcing clay aerogels. Reversible changes in morphology of the aerogel hydrogel composites are observed with varying degrees of hydration.

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

“…casein [21], pectin [22], chitosan [22] and cellulose materials [23][24][25], have been attempted to improve the mechanical property of clay aerogel through bonding neighbouring clays together, which makes the solid in the ice front stable and form bridges between laminar, and such providing the aerogel elasticity through the flexible polymer chain. Among these polymers, poly (vinyl alcohol) (PVA) is widely used for the strong hydrogen bonding between hydroxyl groups and the clay surface [26].…”

Cold Climate Building Enclosure Solutions

“…We estimated and compared the total cost 15 to deep energy wall retrofitting of a baseline house 16 using conventional foam insulations [11]. 17 The conventional foam insulations include rigid board (XPS, EPS, and PIC foams) and spray-applied (closed-cell PU foam) options.…”

“…15 The total cost is the sum of the bare material cost, the bare labor cost, the bare equipment cost plus 10% for profit. 16 The baseline house is a two-story average class residential house with 2,000 ft 2 floor surface area and 2,700 ft Although retrofit applications can apply combined cavity and exterior insulations to reach R-35 thermal resistance, this study considers only exterior installation as compared to VIPs. This is because for the cases considered in this study, the installed cost of combined cavity and exterior installation is higher than the installed cost of just exterior insulation.…”

“…Clay is another less costly and more plentiful substitute. Clay aerogel is produced using a freeze-drying process [16] and consists of stacked sheets of clay with occasional struts connecting these sheets. The thermal resistivity values have been reported to vary between R-4 and R-6/in.…”

Synthesis and characterization of innovative insulation materials

“…During freezing the growing ice fronts cause alignment/shearing of the Na-MMT particles along the ice crystal faces. After high vacuum sublimation, air is trapped in the place of ice crystals, forming a lightweight material with lamellar structure [10,12,14,16]. The formed clay aerogel is a material with low density, low thermal conductivity and low mechanical strength, which can be improved by the use of a reinforcement agent [17][18][19][20][21].…”