Processing and properties of a lightweight fire resistant core material for sandwich structures

A process for syntactic foam made from fly ash, a waste product of coal combustion from thermal power plants, has been developed using phenolic resin binders at low levels. The fly ash consists of hollow glass or ceramic microspheres and needs to be treated to remove contaminants. The production process is easily scalable and can be tailored to produce foams of desired properties for specific applications. Complex shaped parts also are possible with appropriate compression mold tooling. Mechanical properties, compression, tension, shear and fracture toughness, have been determined in this preliminary investigation on this syntactic material and are found to be comparable or better than commercially available core materials. Initial testing for fire resistance has indicated very encouraging results. Further work is being continued to develop this core material with superior mechanical and fire resistance properties.