Synthesis of emulsion-templated porous polyacrylonitrile and its pyrolysis to porous carbon monoliths

PolyHIPEs are emulsion-templated polymers synthesized within high internal phase emulsions (HIPEs). The miscibility of acrylonitrile (AN) with water has made it difficult to synthesize PAN-based polyHIPEs. This paper describes the successful synthesis of PAN-based polyHIPEs by crosslinking through copolymerization with divinylbenzene (DVB), by stabilization with a polyglycerol polyricinoleate surfactant, and by initiation with both oil- and water-soluble initiators. The PAN-based polyHIPEs had porosities of over 86% and porous structures that were different from those of typical polyHIPEs. This paper also describes the production of porous carbon monoliths through the pyrolysis of these PAN-based polyHIPEs. Pyrolysis did not produce significant changes in the porous structures, which were quite similar to those of the original polyHIPEs. The porosities were around 95% and the carbon monoliths were largely macroporous and mesoporous, with some microporosity. These results indicate that PAN-based polyHIPE templates can be used for the a priori design of porous carbon monoliths.