RELEVANCE OF ELASTIC ENERGIES DURING SORPTION OF CO2 MOLECULES IN GLASSY-POLYMERS DEMONSTRATED FOR 2 VERY SIMILAR POLYIMIDES

Data on CO2-sorption in and corresponding volume changes of three poly imides are evaluated in the framework of a recent model where elastic distortion of glassy polymers during dissolution of small molecules is taken into account. Due to the chemical identity and structural simil arity of the polymers, differences in the behavior of CO2 can be attri buted solely to differences in the distribution of the intermolecular space (holes). Thus the polyimide with the lowest volume change has th e smallest elastic energy and, therefore, the largest solubility of CO 2. The evaluation yields values of the average free energy of sorption and the width and average volume of the distribution of holes.