Search

The polymer of intrinsic microporosity PIM-1 was modified by reaction with ethanolamine and with diethanolamine, and the modified polymers characterized by infrared spectroscopy, solid-state NMR spectroscopy, elemental analysis, thermogravimetric analysis and nitrogen adsorption. Various possible reaction products were considered, and the results indicated that hydroxyalkylaminoalkylamide structures were obtained. Gas adsorption measurements showed that ethanolamine modification increased the ideal CO2/N2 selectivity. Studies of dye adsorption from aqueous solution demonstrated that the reaction products showed strong selectivity for the anionic dye Orange II, compared to the cationic dye Safranin O. Mass uptakes of the anionic dye by ethanolamine-modified PIM-1 samples were up to 2 orders of magnitude higher than for the parent polymer. [ABSTRACT FROM AUTHOR]

Nitrile groups in the polymer of intrinsic microporosity PIM-1 were reduced to primary amines using borane complexes. In adsorption experiments, the novel amine-PIM-1 showed higher CO 2 uptake and higher CO 2 /N 2 sorption selectivity than the parent polymer, with very evident dual-mode sorption behavior. In gas permeation with six light gases, the individual contributions of solubility and diffusion to the overall permeability was determined via time-lag analysis. The high CO 2 affinity drastically restricts diffusion at low pressures and lowers CO 2 permeability compared to the parent PIM-1. Furthermore, the size-sieving properties of the polymer are increased, which can be attributed to a higher stiffness of the system arising from hydrogen bonding of the amine groups. Thus, for the H 2 /CO 2 gas pair, whereas PIM-1 favors CO 2 , amine-PIM-1 shows permselectivity toward H 2 , breaking the Robeson 2008 upper bound.