Siloxane and Silane-functionalized Polynorbornenes as Membranes for Passive Carbon Dioxide Separation

In 2012, carbon dioxide (CO₂) [carbon dioxide] accounted for approximately 82% [percent] of all U.S greenhouse gas emissions.¹ These excessive CO2 levels have been attributed to climate changes that have a range of negative effects on human health and welfare.1 In an effort to decrease these emissions, polymeric membranes consisting of silane- and siloxane-functionalized norbornene units have been targeted as a potential solution for the passive separation of CO2 from other non-greenhouse gases. These substituted norbornene-based polymers were synthesized via vinyl-addition polymerization. Through a series of catalyst trials, commercially available palladium and nickel catalysts were compared along with trans-[Ni(C₆F₅)₂(SbPh₃)₂] [transbis( pentafluorophenyl)bis(triphenylstibine)nickel] to determine the catalytic activity for various silane- and siloxane-functionalized norbornene derivatives. It was observed that trans-[Ni(C₆F₅)₂(SbPh₃)₂] overall had the highest activity for these types of monomers. Subsequently, free-standing films were formed from these functionalized norbornenebased polymers by utilization of a “dry/wet-phase inversion” technique. Through a collaboration with Oak Ridge National Laboratory, these novel membranes were analyzed and subsequently evaluated using Robeson Plots as a gauge of efficiency and real-world viability.