(750d) Polymers with Intrinsic Micro Porosity (PIM-1) Based Compatible Blend Membranes for CO2 Separation Applications

Ali K. Sekizkardes^1,2, Samir Budhathoki,^1,2 Surendar Venna,^1,2 Victor Kusuma,^1,2 David Hopkinson ¹

¹ U.S. Department of Energy National Energy and Technology Laboratory,

Pittsburgh, Pennsylvania 15236, USA.

² Leidos Research Support Team, Pittsburgh, Pennsylvania 15236, USA.

Microporous polymers such as polymers with intrinsic microporosity (PIMs) have shown great potential in gas separation membrane applications due to their facile synthesis, easy processability and high gas permeability. However, the polymer structure of PIM-1 consists of non-polar and large micro pores (>1nm) resulting in lower CO₂ selectivity and weak mechanical properties when processed in membrane films. We address these drawbacks of PIM-1 by developing blend membranes fabricated with PIM-1 and polyphosphazenes. Characterization of these membranes showed an improvement in the brittle film properties of PIM-1 by greatly altering the strain to failure of PIM-1 from 1% to as high as 10.5%, which is indicative of a very flexible and durable film formation. In addition, very high CO₂ permeability (~2000 Barrer) and selectivity (~30) were recorded for the membranes. The membranes lie on the Robeson upper bound which is an empirical limit for the gas separation performance of polymer membranes. Here we also studied the structure property relationship between these two blending polymers, both experimentally and computationally, by altering the chemical structure of the polymers. Membrane fabrication, characterization and gas transport testing will be presented.

Reference

Sekizkardes, A. K.; Kusuma, V. A.; McNally, J. S.; Gidley, D. W.; Resnik, K.; Venna, S. V.; Hopkinson, D. “Microporous polymeric composite membranes with advanced film properties: pore intercalation yields excellent CO₂ separation performance” Journal of Materials Chemistry A 2018, 6, 22472-22477.