Carbon-carbon composite foams with high specific strength from sucrose and milled carbon fiber

•Carbon composite foams were prepared from molten sucrose and milled carbon fiber.•The microstructure and mechanical properties depend on carbon fiber length.•The highest compressive strength is achieved at low fiber concentration of 2 wt.%.•Maximum of 125% improvement in the compressive strength was achieved.

Carbon composite foams prepared by the thermo-foaming of milled carbon fiber dispersions in molten sucrose were evaluated for microstructure and mechanical properties as a function of average fiber length and fiber concentration. The density and specific compressive strength of the carbon composite foams increased with a decrease of average fiber length and reached a maximum at an average fiber length of 33 μm. A maximum increase in compressive strength of 125% and specific compressive strength of 92% was obtained at a carbon fiber concentration of 2 wt.%.