Phenolic syntactic foams: Low-density composites for structural and thermostructural applications

Syntactic foams, low density composites consisting of hollow microballoons or microspheres dispersed in a matrix, find application in various fields. The properties of these light weight composites can be easily tuned by suitably selecting the matrix and the hollow microsphere filler and their composition. Among the various matrices employed in syntactic foams, phenolic resins have enticed the researchers owing to their salient features viz. high thermal stability, high char yield, structural integrity etc. This review gives an overview of phenolic syntactic foams with a focus on various phenolic resin based syntactic foams and modified syntactic foams. Finally, applications of phenolic syntactic foams are also covered.