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Foam-like polymer/clay aerogels which incorporate air bubbles



The structure/property relationships of polymer/clay aerogels interfused with uniformly distributed air bubbles were examined. Through the incorporation of a polyelectrolyte in a montmorillonite(MMT) clay solution, the viscosity was systematically changed by the addition of ions with different charges. The bubbles were achieved via high speed mixing and were stabilized through the use of the surfactant sodium dodecyl sulfate (SDS). As the charge of the ion increased from +1 (Na+ ions) to +2 (Ca2+ ions) to finally +3 (Al3+ ions), the modulus of the resultant aerogels increased. The foamed polymer/clay aerogels showed a reduction in thermal conductivity while retaining similar mechanical properties to unfoamed polymer/clay aerogels. The most promising composition was one which contained 5% MMT clay/5% poly(vinyl alcohol)/0.5% xanthum gum/0.5% SDS/0.2% Al2(SO4)3·6(H2O) possessing a density of 0.083 g/cm3, an average modulus of 3.0 MPa, and a thermal conductivity of 41 W/m·K. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39546.