Gas Transport Properties of Hydrogenated and Fluorinated Polynorbornene Dicarboximides

The synthesis and further hydrogenation of fluorinated polynorbornene dicarboximides is reported, using p‐toluenesulfonyl hydrazide and Wilkinson's catalysts, respectively. Despite improving the resistance to thermo‐oxidative degradation, it is observed that the hydrogenation of the backbone double bonds in the polymer also decreases the thermomechanical properties. Afterward, a comparative study of gas transport in membranes based on these hydrogenated polynorbornenes, as well as in their unsaturated analogues, is carried out. The gases studied are hydrogen, oxygen, nitrogen, carbon dioxide, methane, ethane, ethylene, and propylene. After hydrogenation, the gas permselectivity of the membranes is enhanced as a consequence of the decrease of both the gas solubility and the gas diffusion. A series of unsaturated fluorinated polynorbornene dicarboximides prepared by ring‐opening metathesis polymerization (ROMP) is successfully hydrogenated yielding new saturated materials. A comparison of the gas transport properties in membranes prepared from hydrogenated polynorbornenes, as well as from their unsaturated analogues, shows an enhancement of the gas permselectivity after the hydrogenation step.