Novel copolyimides containing adamantyl pendant groups. Synthesis and gas permeation properties

摘要

Three novel copolyimides bearing adamantane pendant groups have been prepared by chemical modification of a copolyimide precursor containing carboxylic acid groups. Thermal analyses indicated that, depending on the adamantyl substitution site, the polymer thermal decomposition followed a different path, showing various stages and at different temperatures.rnThe permeability coefficients of all the adamantane-containing copolyimides were higher than that of the carboxy-containing copolyimide precursor, up to seven times higher, depending on the gas tested. The increase on permeability was associated to the increase on the diffusion parameter brought about by the bulkiness of the adamantane pendant groups.