Enhancing the Gas Permeability of Tröger's Base Derived Polyimides of Intrinsic Microporosity

A series of four novel Tröger's base (TB) derived polyimides of intrinsic microporosity (PIM-TB-PI) is reported. The TB diamine monomer (4MTBDA) possesses four methyl groups in order to restrict rotation about the C-N imide bonds in the resulting polymers. The polymers possess apparent BET (Brunauer, Emmett, and Teller) surface areas between 584 and 739 m2 g-1, complete solubility in chloroform, excellent molecular mass, high inherent viscosity and good film-forming properties. Gas permeability measurements demonstrate enhanced performance over previously reported polyimide-based Tröger's base (TB) polymers confirming the benefit of the additional methyl groups within the TB diamine monomer. Notably, a polyimide derived from 4MTBDA and pyromellitic anhydride (PMDA) demonstrates gas permeability data above the 2008 upper bounds for important gas pairs such as O2/N2, H2/N2, and H2/CH4. © 2016 American Chemical Society.