Results are reported of research on intumescent composites based on epoxy resin cross-linked with polyethylene polyamine and containing ammonium polyphosphate and such modifying additives as calcium borate, manganese dioxide, nickel, and chromium, containing tubulenes as gas-formers and carbonization stimulators. The changes in composition and physicochemical properties of modified compositions under conditions of heat and fire were investigated by X-ray photo-electron spectroscopy, atomic force microscopy, and local force spectroscopy. Ammonium polyphosphate mainly stimulates carbonization processes on the inner surface of a bubble being formed during foam coke formation. The introduction of metal-containing tubulenes leads to the formation of fire-retardant and low flammability-compositions with high coke and carbon structures content. The use of calcium borate in the compositions considerably increases the strength of foam coke being formed.