(566b) Synthesis and Gas Separation Performances for Substituted Polynorbornene

In recent decades, significant attention has been given to designing polymeric membranes for energy-efficient gas separation. A major challenge in membrane designing is to overcome the trade-off between gas permeability and selectivity, thereby improving membrane performance. Within this framework, polynorbornene has emerged as a promising material due to its thermal stability, and highly tunable and rigid chemical structure. Recent studies have shown that polynorbornene synthesized through Ring Opening Metathesis Polymerization (ROMP) and Vinyl-addition Polymerization (VAP) with varying side groups, can be used to form membranes with improved gas separation performance and selectivity. This study focuses on the synthesis of polynorbornene from ROMP and VAP using commercially available 5-phenyl-2-norbornene, with variations in the position of the arene R group. Gas transport properties are assessed through gas permeation studies, aiming to analyze the gas diffusivity mechanism and selectivity for these tunable materials. Membranes were fabricated by solution casting. Gas sorption was used to directly measure solubility, while single and mixed gas permeation studies were used to investigate the permeability and competitive sorption for gases including CO₂, N₂, O₂, and He. These results provide valuable insights into the structure-property relationships of polynorbornene for advanced gas separation applications.