Foam-like materials produced from abundant natural resources

Low density polymer/clay aerogel composites were prepared using casein and sodium montmorillonite clay (Na+-MMT). The use of naturally occurring polymers allows for the creation of environmentally friendly/benign materials. Using a freeze drying process, composites were made that have densities in the range of 0.08–0.15 g cm−3 and exhibit properties similar to typical foamed polymers such as expanded polystyrene and rigid polyurethane foams. It was found that a minimum of at least 5wt% casein is required in the initial aqueous mixture in order to create a viable structure. The casein-containing materials created using this freeze drying process are similar to those previously produced with synthetic water soluble polymers such as poly(vinyl alcohol) but exhibit superior mechanical properties when compared to any synthetic polymer/clay aerogel composite tested to date.