Polyvinylnorbornene Gas Separation Membranes

Substituted polynorbornene membranes: a modular template for targeted gas separations

This perspective focuses on substituted polynorbornenes as a promising modular platform to access advanced gas separation membranes, and highlights their synthetic versatility and robust performance.

Synthesis and Gas Transport Properties of Addition Polynorbornene with Perfluorophenyl Side Groups

Polynorbornenes represent a fruitful class of polymers for structure–property study. Recently, vinyl-addition polynorbornenes bearing side groups of different natures were observed to exhibit excellent gas permeation ability, along with attractive C₄H₁₀/CH₄ and CO₂/N₂ separation selectivities. However, to date, the gas transport properties of fluorinated addition polynorbornenes have not been reported. Herein, we synthesized addition polynorbornene with fluoroorganic substituents and executed a study on the gas transport properties of the polymer for the first time. A norbornene-type monomer with a C₆F₅ group, 3-pentafluorophenyl-exo-tricyclononene-7, was successfully involved in addition polymerization, resulting in soluble, high-molecular-weight products obtained in good or high yields. By varying the monomer concentration and monomer/catalyst ratio, it was possible to reach M_w values of (2.93–4.35) × 10⁵. The molecular structure was confirmed by NMR and FTIR analysis. The contact angle with distilled water revealed the hydrophobic nature of the synthesized polymer as expected due to the presence of fluoroorganic side groups. A study of the permeability of various gases (He, H₂, O₂, N₂, CO₂, and CH₄) through the prepared polymer disclosed a synergetic effect, which was achieved by the presence of both bulky perfluorinated side groups and rigid saturated main chains. Addition poly(3-pentafluorophenyl-exo-tricyclononene-7) was more permeable than its metathesis analogue by a factor of 7–21, or the similar polymer with flexible main chains, poly(pentafluorostyrene), in relation to the gases tested. Therefore, this investigation opens the door to fluorinated addition polynorbornenes as new potential polymeric materials for membrane gas separation.

Recent developments on polymeric membranes for CO2 capture from flue gas

Polymeric membranes have been widely considered as one of the next-generation technologies for CO2 capture from fossil fuel-derived flue gases. This separation modality requires novel polymeric materials that possess efficient CO2/N2 separation properties, as well as chemical and mechanical stability for a multiyear membrane lifetime. In this paper, recent developments in polymeric membranes tailored for post-combustion carbon capture are reviewed. The selected polymeric materials encompass ether oxygen-rich polymers, polynorbornenes, ionic liquid membranes, and facilitated transport membranes. In each of the selected materials, noteworthy research efforts for material design and membrane formation are highlighted. The performances of the selected materials are compared in the CO2/N2 selectivity-CO2 permeance plot. As the only class of materials reviewed herein that have demonstrated the fabrication of thin-film composite membranes in scale, facilitated transport membranes have shown both high selectivity and permeance at relevant conditions for post-combustion carbon capture. However, comprehensive field tests are needed to resolve the technical gap between the material development and the commercial application.

Microporous Organic Polymers: Synthesis, Characterization, and Applications

The presence of a certain degree of porosity in polymers is a feature that provides them with unique properties and with opportunities to be exploited in a number of technologically important applications [...].