Tailoring the pore size of hypercrosslinked polymer foams

Organic analogues to inorganic zeolites would be a significant step forward in engineered porous materials and would provide advantages in range, selectivity, tailorability and processing. Rigid molecular foams or ''organic zeolites'' would not be crystalline materials and could be tailored over a broader range of pore sizes and volumes. A novel process for preparing hypercrosslinked polymeric foams has been developed via a Friedel-Crafts polycondensation reaction. A series of rigid hypercrosslinked foams have been prepared using simple rigid polyaromatic hydrocarbons including benzene, biphenyl, m-terphenyl, diphenylmethane, and polystyrene, with p-dichloroxylene (DCX) or divinylbenzene (DVB) as the crosslinking agent. Transparent gels are formed suggesting avery small pore size. After drying the foams are robust and rigid. Densities of the resulting foams can range from 0.15 g/cc to 0.75 g/cc. Nitrogen adsorption studies have shown that by judiciously selecting monomers and crosslinking agent along with the level of crosslinking and the cure time of the resulting gel, the pore size, pore size distribution, and the total surface area of the foam can be tailored. Surface areas range from 160 to 1,200 m(2)/g with pore sizes ranging from 6 Angstrom to 2,000 Angstrom. Further evidence of the uniformity of the foams and their pore sizes has been confirmed by high resolution TEM.