coating compositions for blocking heat from hyperthermal sources are reinforced with high - temperature , high emissivity , open weave fabrics . the coating compositions contain materials which actively respond to excessively high temperatures by undergoing endothermic processes or by swelling , preferably by both . the preferred fabrics are made of graphite or cardo - polymer yarns . the reinforced compositions may be applied directly to a substrate , or they may be molded into self - supporting shapes which are applied to the substrate or are themselves structural units .