Development of biodegradable foamlike materials based on casein and sodium montmorillonite clay.

Biodegradable foamlike materials based on a naturally occurring polymer (casein protein) and sodium montmorillonite clay (Na+ -MMT) were produced through a simple freeze-drying process. By utilizing DL-glyceraldehyde (GC) as a chemical cross-linking agent, the structural integrity of these new aerogels were remarkably improved when compared to those of the control system (without GC), with a minimal increase in the density from 0.11 to 0.12 g cm⁻³. The degree of perfection of the foamlike structures was another parameter that had a significant influence on the physical and thermal performances of the low density composites. The biodegradability of the aerogels was investigated in terms of the carbon dioxide (CO₂) evolution for up to 8 weeks in compost media under controlled conditions.