Abstract
An innovative powder-foaming process able to produce thermal and acoustic insulating foams obtained by sol-gel and a subsequent freeze-drying process was developed. Gel containing glass powder was formed using alginate, a polysaccharide composed of 1-4linked α-L-guluronic acid and β-D-mannuronic acid, capable to form stable gels in presence of calcium cations. In order to obtain a porous foam, gels were frozen and then freeze-dried. Foam properties strongly depend on production parameters, particle dimension and different binder concentrations, their influence was investigated. The resulting glass foams were characterized in order to evaluate structure, density, mechanical and acoustic properties. The results pointed out an improved acoustic insulating performance respect to rock wool. Foams were also subjected to a thermal process to better fix powders into the final glass structure.