(666b) Adsorption in TB-Polymers of Intrinsic Microporosity

Polymers of Intrinsic Microporosity (PIMs) display some features from traditional rigid adsorbents and polymeric materials. They are formed from monomers that contain contortion sites and prevents the polymer from packing efficiently, creating a microporous volume accessible for adsorbents. Due to the rigidity of the polymer chain, often formed by a series of fused aromatic rings, their swelling is significantly smaller than conventional polymeric materials. Some properties in PIMs can be tuned by functionalising the monomers to create specific interactions between the framework and adsorbed molecules. For example, the incorporation of amino groups is expected to increase the affinity of the polymers towards polar molecules such as carbon dioxide. In this work, we present the adsorption properties of a family of PIMs that contain Troger base (TB) units as part of their monomers. TB units are expected to provide basic adsorption sites where carbon dioxide can adsorb preferentially.  We have analysed the effect of TB in a series of PIMs with different structures (linear chains, branched and networks) and have demonstrated that the presence of TB units favours adsorption of CO2 at low pressures, but reduces the capacity of the material at high pressures. The reduction in the capacity of the material at high pressures is related in some cases to a smaller initial microporous volume or to a smaller capacity of the polymer to swell, which depends on the structure of the polymer rather than on the details of its chemistry.