SBIR-STTR Award

While often touted as the best solution to high temperature thermal protection systems, decades of funding have yielded only incremental improvements and very few applications for carbon aerogels. A.W. Cain & Company incorporated in 2019 to implement a new approach to solid gel manufacturing patented by Southern Research (SR). The water-based chemistry results in gels that can be air-dried immediately and can then be cyclically wet and dried without significant degradation. Experimentation has shown that both inorganic salt solutions and organic polymers will distribute through the solid structure of the gel. A.W. Cain & Company is proposing to fully transfer the technology from Southern Research during Phase I, while demonstrating the ability to make two different organic gels that can be pyrolized to form carbon structures and further modified to form low density ceramics with open porosity. Combined with ceramic forming polymer technology, the SR gels can be used as low cost preforms for ultrahigh temperature ceramics without the need for chemical vapor infiltration to fully densify, or the open porosity can be utilized in heat pipes, molten electrode batteries, or other high-temperature phase change systems.

The Phase I demonstrated the ability to make continuous nanophase carbon/silicon carbide (C/SiC) composites with open porosity by chemical modification of nanoporous organic solid gels. We expect the resulting Gel-derived Trabecular Solid (GTS) to demonstrate good electromagnetic (EM) shielding properties, as a consequence of combined conductive and dielectric domains. These materials have a continuous, highly branched C-strut and C-wall substructure with open pores, whose entire surface, internal and exterior, is well coated with “SiC” (i.e., an amorphous Si-C-O-N ceramic glass containing nano-sized SiC crystals) which is derived from pyrolysis of Si-based polymers containing alkyl side-groups. This kind of microstructure, where the conductive phase is a continuous ensemble of interconnected small, thin walls, beams, and struts, rather than isolated domains, is similar to that of some of the best reported EM shielding composites made from distribution of carbon nanotubes in a polymer matrix to form a network of conductive elements. The EM shielding properties these new C-core/SiC-shell materials should be quite good and will be measured in the microwave portion of the EM spectrum for varied core-shell compositio