Foamed Cores

Abstract

Foamed cores are widely employed in lightweight structures, in particular, sandwich structures where they are used in alternative to honeycombs. Among the advantages compared to honeycombs foams show higher thermal and acoustic insulation and higher resistance to humidity and barrier to vapor and gases. Foamed cores in sandwich structures are usually based on polymeric matrices. The cellular structure of these lightweight materials is usually obtained through a controlled nucleation and growth of gas bubbles within a polymeric melt, in the case of thermoplastics or during the polymerization reactions occurring in the case of thermosets. Metallic foams are employed in applications where very high impact energy is required or when service temperatures exceed 200–250°C. At service temperature above 500–600°C ceramic porous structures are preferred.