In the United States, approximately 50% of the total energy consumed annually by the chemicals industry (16 quadrillion BTUs) is for separation processes. Distillation uses about 53% of the energy consumed by separation processes. Replacing distillation with membrane-based separations could save $4B in energy costs and 100M tonnes of greenhouse emissions annually. Commercial membranes made of polymers like cellulose acetate perform industrial separations, but show instability in aggressive environments (e.g., plasticization) and suboptimal performance that prevents broader adoption of membrane technologies. To address these limitations, microporous polymers featuring rigid, pore-generating side chains on flexible backbones were synthesized through a reaction based on Ring Opening Metathesis Polymerization (ROMP). Macro-monomers formed by Diels-Alder reactions are converted into high molecular weight polymer with low polydispersity by ROMP. Compared to commercial membranes, poly(ladder) ROMP films demonstrate a ~10-fold increase in stability against CO2-induced plasticization and, for CF3-ROMP, record-breaking permeability for CO2, ideal for carbon capture applications. However, first-generation poly(ladder) ROMPs form brittle films--hindering their commercial implementation. Altering macro-monomer length and grafting density provides insight into polymer designs that result in improvements to mechanical elasticity, unprecedented plasticization resistance, and remarkable gas separation performance in poly(ladder) ROMPs. Co-polymerization with simple norbornenes alters grafting density and results in more elastic, easy-to-process films. To investigate sidechain length impact on mechanical elasticity, macro-monomers were separated via silica gel chromatography before undergoing ROMP to form poly(ladder) ROMPs with monodisperse sidechains. Increasing sidechain length decreases film fragility, improves gas separation performance, and boosts plasticization resistance.

Next generation poly(ladder) ROMPs: Altering grafting density and sidechain degree of polymerization for improved stability

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.