Fabrication of Reticulated Graphitic Foam

Carbon foams have applications where light weight and high temperature resistant materials are required. A 3D morphology can be obtained, forming an intricate network of interconnecting struts. These struts have the potential to simulate graphitic carbon fibers with a high specific strength, high specific stiffness, high thermal conductivity, and extreme high temperature stability. Potential applications of carbon foams include: fugitive phase for inverse metal foams, rapid thermal capacitors, catalyst substrates, 3D composite reinforcement, and caustic and biological filters. Carbon foams have been produced using blowing agents such as carbon dioxide and nitrogen, however these foams contain closed cells and have a microcellular morphology. The goal of the present work is to produce a graphitic carbon foam with open cells on the order of 10 to 18 ppi (pores per inch). A technique has been developed using polyurethane foam as a fugitive phase. The polyurethane foam is dipped into a solution of mesophase pitch (MP). Mesophase pitch is a carbon precursor, in the present case, derived from naphthalene. The advantage of MP is that it is easily graphitized. The flow of the MP over the struts gives some initial molecular orientation. The dipped foam is dried, leaving behind a the polyurethane foam coated with the pitch. The foam then goes through several heat treatments to stabilize the mesophase pitch, burn out the polyurethane, carbonize and finally graphitize the foam, all the while maintaining the same morphology as the initial polyurethane foam.Air Force Inst of Tech Wright-Patterson AFB OH is the author of 'Fabrication of Reticulated Graphitic Foam' with ISBN 9781423584575 and ISBN 1423584570.