{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/153404"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/153404","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Mixed-gas Transport in Microporous Polymer Derivatives for Energy-Efficient Gas Separations","abstract":"Over the past forty years, membrane-based gas separations have emerged as a promising alternative to energy-intensive separation processes such as amine absorption and cryogenic distillation. However, a trade-off between permeability and selectivity as well as issues of decreased performance at high pressures have hindered widespread membrane deployment. In response, there is a growing body of research aimed to developing materials formulations that address these polymer-specific disadvantages. Polymers of intrinsic microporosity (PIMs) were designed as ultrahigh-free-volume materials with inefficient chain packing and high surface areas, resulting in pure-gas performance beyond that of traditional glassy polymers. Hybrid systems such as mixed-matrix membranes (MMMs) also emerged as a means of increasing overall separation performance and reducing plasticization. Despite the surge in available material platforms for membrane-based separations, the performance and fundamental underpinnings of binary and ternary mixed-gas transport in these microporous polymers and MMMs remains underexplored. This thesis combines synthetic chemistry, materials science, and chemical engineering to develop a platform of functionalized PIM derivatives and to investigate their pure- and mixed-gas transport properties in industrially relevant conditions. Approaches to increase diffusion-based performance in PIMs are developed, including methods to functionalize PIMs with carboxylic acid and amine functionalities, template free volume elements through protection/de-protection chemistries, and fabricate MOF–polymer composites. The effects of polymer functionalization, free volume manipulation, and membrane hybridization on transport are investigated via pure-gas testing and sorption–diffusion analysis, to elucidate structure–property relationships between polymer packing structure and gas diffusion. Polymers with identical backbone structures and varying backbone functionality are subsequently used as a platform to investigate the effects of CO₂ sorption affinity on the binary and ternary mixed-gas transport. Among the PIMs considered, amine-functionalized PIM-1 shows a notable increase in mixed-gas selectivity compared to the pure-gas case. The generalizability of this approach is investigated through aminefunctionalization of a different family of polymers, poly(aryl ether)s (PAEs). Results indicate that amine-functionalization can serve as a promising route to increase mixed-gas transport performance while also reducing CO₂-based plasticization. The influence of CO₂ sorption affinity on transport is finally investigated through ternary mixed-gas tests in toxic gas mixtures containing H₂S. Taken together, this thesis derives connections between macromolecular chemistry and complex gas transport performance in PIMs. By developing these structure-property-performance relationships, this work provides context for the potential of PIMs in industrial applications and rational design handles for future development of high-performing membrane solutions.","abstract_html":"Over the past forty years, membrane-based gas separations have emerged as a promising alternative to energy-intensive separation processes such as amine absorption and cryogenic distillation. However, a trade-off between permeability and selectivity as well as issues of decreased performance at high pressures have hindered widespread membrane deployment. In response, there is a growing body of research aimed to developing materials formulations that address these polymer-specific disadvantages. Polymers of intrinsic microporosity (PIMs) were designed as ultrahigh-free-volume materials with inefficient chain packing and high surface areas, resulting in pure-gas performance beyond that of traditional glassy polymers. Hybrid systems such as mixed-matrix membranes (MMMs) also emerged as a means of increasing overall separation performance and reducing plasticization. Despite the surge in available material platforms for membrane-based separations, the performance and fundamental underpinnings of binary and ternary mixed-gas transport in these microporous polymers and MMMs remains underexplored. This thesis combines synthetic chemistry, materials science, and chemical engineering to develop a platform of functionalized PIM derivatives and to investigate their pure- and mixed-gas transport properties in industrially relevant conditions. Approaches to increase diffusion-based performance in PIMs are developed, including methods to functionalize PIMs with carboxylic acid and amine functionalities, template free volume elements through protection/de-protection chemistries, and fabricate MOF–polymer composites. The effects of polymer functionalization, free volume manipulation, and membrane hybridization on transport are investigated via pure-gas testing and sorption–diffusion analysis, to elucidate structure–property relationships between polymer packing structure and gas diffusion. Polymers with identical backbone structures and varying backbone functionality are subsequently used as a platform to investigate the effects of CO₂ sorption affinity on the binary and ternary mixed-gas transport. Among the PIMs considered, amine-functionalized PIM-1 shows a notable increase in mixed-gas selectivity compared to the pure-gas case. The generalizability of this approach is investigated through aminefunctionalization of a different family of polymers, poly(aryl ether)s (PAEs). Results indicate that amine-functionalization can serve as a promising route to increase mixed-gas transport performance while also reducing CO₂-based plasticization. The influence of CO₂ sorption affinity on transport is finally investigated through ternary mixed-gas tests in toxic gas mixtures containing H₂S. Taken together, this thesis derives connections between macromolecular chemistry and complex gas transport performance in PIMs. By developing these structure-property-performance relationships, this work provides context for the potential of PIMs in industrial applications and rational design handles for future development of high-performing membrane solutions.","abstract_has_math":false,"creators":["Mizrahi Rodriguez, Katherine"],"institution":"Massachusetts Institute of Technology","degree_name":"Doctoral","degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Materials Science and Engineering","school":null,"contributors":[],"advisors":["Smith, Zachary P."],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-05","date_published":"2022-05","updated_at":"2026-07-22T22:21:47Z","subjects":[],"languages":[],"rights":["In Copyright - Educational Use Permitted","Copyright MIT"],"rights_urls":["http://rightsstatements.org/page/InC-EDU/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1721.1/153404","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Smith, Zachary P."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. 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However, a trade-off between permeability and selectivity as well as issues of decreased performance at high pressures have hindered widespread membrane deployment. In response, there is a growing body of research aimed to developing materials formulations that address these polymer-specific disadvantages. Polymers of intrinsic microporosity (PIMs) were designed as ultrahigh-free-volume materials with inefficient chain packing and high surface areas, resulting in pure-gas performance beyond that of traditional glassy polymers. Hybrid systems such as mixed-matrix membranes (MMMs) also emerged as a means of increasing overall separation performance and reducing plasticization. Despite the surge in available material platforms for membrane-based separations, the performance and fundamental underpinnings of binary and ternary mixed-gas transport in these microporous polymers and MMMs remains underexplored. This thesis combines synthetic chemistry, materials science, and chemical engineering to develop a platform of functionalized PIM derivatives and to investigate their pure- and mixed-gas transport properties in industrially relevant conditions. Approaches to increase diffusion-based performance in PIMs are developed, including methods to functionalize PIMs with carboxylic acid and amine functionalities, template free volume elements through protection/de-protection chemistries, and fabricate MOF–polymer composites. The effects of polymer functionalization, free volume manipulation, and membrane hybridization on transport are investigated via pure-gas testing and sorption–diffusion analysis, to elucidate structure–property relationships between polymer packing structure and gas diffusion. Polymers with identical backbone structures and varying backbone functionality are subsequently used as a platform to investigate the effects of CO₂ sorption affinity on the binary and ternary mixed-gas transport. Among the PIMs considered, amine-functionalized PIM-1 shows a notable increase in mixed-gas selectivity compared to the pure-gas case. The generalizability of this approach is investigated through aminefunctionalization of a different family of polymers, poly(aryl ether)s (PAEs). Results indicate that amine-functionalization can serve as a promising route to increase mixed-gas transport performance while also reducing CO₂-based plasticization. The influence of CO₂ sorption affinity on transport is finally investigated through ternary mixed-gas tests in toxic gas mixtures containing H₂S. Taken together, this thesis derives connections between macromolecular chemistry and complex gas transport performance in PIMs. By developing these structure-property-performance relationships, this work provides context for the potential of PIMs in industrial applications and rational design handles for future development of high-performing membrane solutions."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph.D."]},{"key":"dc:title","label":"Title","values":["Mixed-gas Transport in Microporous Polymer Derivatives for Energy-Efficient Gas Separations"]}]}],"canonical_facts":{"dc:contributor.advisor":["Smith, Zachary P."],"dc:contributor.department":["Massachusetts Institute of Technology. Department of Materials Science and Engineering"],"dc:creator":["Mizrahi Rodriguez, Katherine"],"dc:date.accessioned":["2024-01-24T19:28:52Z"],"dc:date.available":["2024-01-24T19:28:52Z"],"dc:date.issued":["2022-05"],"dc:description.abstract":["Over the past forty years, membrane-based gas separations have emerged as a promising alternative to energy-intensive separation processes such as amine absorption and cryogenic distillation. However, a trade-off between permeability and selectivity as well as issues of decreased performance at high pressures have hindered widespread membrane deployment. In response, there is a growing body of research aimed to developing materials formulations that address these polymer-specific disadvantages. Polymers of intrinsic microporosity (PIMs) were designed as ultrahigh-free-volume materials with inefficient chain packing and high surface areas, resulting in pure-gas performance beyond that of traditional glassy polymers. Hybrid systems such as mixed-matrix membranes (MMMs) also emerged as a means of increasing overall separation performance and reducing plasticization. Despite the surge in available material platforms for membrane-based separations, the performance and fundamental underpinnings of binary and ternary mixed-gas transport in these microporous polymers and MMMs remains underexplored. This thesis combines synthetic chemistry, materials science, and chemical engineering to develop a platform of functionalized PIM derivatives and to investigate their pure- and mixed-gas transport properties in industrially relevant conditions. Approaches to increase diffusion-based performance in PIMs are developed, including methods to functionalize PIMs with carboxylic acid and amine functionalities, template free volume elements through protection/de-protection chemistries, and fabricate MOF–polymer composites. The effects of polymer functionalization, free volume manipulation, and membrane hybridization on transport are investigated via pure-gas testing and sorption–diffusion analysis, to elucidate structure–property relationships between polymer packing structure and gas diffusion. Polymers with identical backbone structures and varying backbone functionality are subsequently used as a platform to investigate the effects of CO₂ sorption affinity on the binary and ternary mixed-gas transport. Among the PIMs considered, amine-functionalized PIM-1 shows a notable increase in mixed-gas selectivity compared to the pure-gas case. The generalizability of this approach is investigated through aminefunctionalization of a different family of polymers, poly(aryl ether)s (PAEs). Results indicate that amine-functionalization can serve as a promising route to increase mixed-gas transport performance while also reducing CO₂-based plasticization. The influence of CO₂ sorption affinity on transport is finally investigated through ternary mixed-gas tests in toxic gas mixtures containing H₂S. Taken together, this thesis derives connections between macromolecular chemistry and complex gas transport performance in PIMs. By developing these structure-property-performance relationships, this work provides context for the potential of PIMs in industrial applications and rational design handles for future development of high-performing membrane solutions."],"dc:description.degree":["Ph.D."],"dc:identifier.uri":["https://hdl.handle.net/1721.1/153404"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["In Copyright - Educational Use Permitted","Copyright MIT"],"dc:rights.uri":["http://rightsstatements.org/page/InC-EDU/1.0/"],"dc:title":["Mixed-gas Transport in Microporous Polymer Derivatives for Energy-Efficient Gas Separations"],"dc:type":["Thesis"],"thesis:degree_name":["Doctoral","Doctor of Philosophy"]},"updated_at":"2026-07-22T22:21:47Z"}