Site Loader
Rock Street, San Francisco

A novel Polymer of Intrinsic Microporosity (PIM) was prepared from a diaminobenzotriptycene monomer using a polymerization reaction based on Tröger’s base formation. The polymer (PIM-BTrip-TB) demonstrated an apparent BET (Brunauer, Emmet and Teller) surface area of 870 m2 g?1, good solubility in chloroform, excellent molecular mass, high inherent viscosity, and provided robust thin films for gas permeability measurements. The polymer is highly permeable (e.g. PH2 = 9980; PO2 = 3290 Barrer) with moderate selectivity (e.g. PH2/PN2 = 11.0; PO2/PN2 = 3.6) so that its data lie over the 2008 Robeson upper bounds for the H2/N2, O2/N2 and H2/CH4, gas pairs and on the upper bound for CO2/CH4. On ageing, the polymer demonstrates a drop in permeability, which is typical for ultrapermeable polymers, but with a significant increase in gas selectivities, (e.g., PO2 = 1170 Barrer; PO2/PN2 = 5.4).The preparation of new polymeric membranes for gas separation is receiving increasing attention by both academia and industry,1 as a result of their potential for a number of important separations, including O2/N2,2 for the production of oxygen-enriched or depleted air, CO2/CH43 for natural gas enrichment, CO2/N24 for carbon capture and H2/N2 and H2/CO25 for the recovery and production of hydrogen6. The performance of membranes for gas separation is typically evaluated by measuring the permeability of single species (Px and Py) and calculating the ideal selectivity of one component of a gas pair towards the other (?xy = Px/Py). It was found that the vast majority of the polymers suffer a trade-off relationship between these two values so that highly selective polymers have low permeability and vice versa. This relationship was empirically quantified by Robeson7 and then theoretically explained by Freeman.8 Following these studies, it was suggested that, to surpass the Robeson upper bounds, it was necessary to prepare polymers with higher internal free volume, by increasing inter-chain distances, and enhanced backbone rigidity. Polymers of Intrinsic Microporosity (PIMs), first reported in 2004,9 in which a highly rigid and contorted macromolecular structure ensures high free volume, conform to this design strategy.10 Recently, we reported a new class of PIMs prepared using the efficient formation of the highly rigid and contorted bicyclic diamine called Tröger’s base (PIM-TB).11 When the polymerisation was performed using a diamine monomer containing a bridged bicyclic structure, such as 2,6(7)-diamino-9,10-dimethylethanoanthracene,12 a highly rigid polymer was prepared (PIM-EA-TB, 

Post Author: admin


I'm Dora!

Would you like to get a custom essay? How about receiving a customized one?

Check it out