RT info:eu-repo/semantics/article T1 Gas permeability through polyimides: Unraveling the Influence of free volume, intersegmental distance and glass transition temperature A1 Torres, Alba A1 Soto Guzmán, Marvelia Cenit A1 Carmona, Francisco Javier A1 Comesaña Gándara, Bibiana A1 Viuda, Mónica de la A1 Palacio Martínez, Laura A1 Prádanos del Pico, Pedro Lourdes A1 Simorte, María Teresa A1 Sanz, Inmaculada A1 Muñoz Torre, Raúl A1 Tena Matías, Alberto A1 Hernández Giménez, Antonio K1 Gas separation membranes K1 Membrane separation K1 Gases - Separation K1 Membranas (Tecnología) K1 Polymers K1 Polimeros y polimerización K1 Glass transition temperature K1 Glass K1 2204.05 Gases K1 2210.19 Fenómenos de Membrana K1 2206.10 Polímeros K1 3312.06 Vidrio AB The relationships between gas permeability and free volume fraction, intersegmental distance, and glass transition temperature, are investigated. They are analyzed for He, CO2, O2, CH4, and N2 gases and for five similar polyimides with a wide range of permeabilities, from very low to extremely high ones. It has been established here that there is an exponential relationship between permeability and the free volume fraction, and between permeability and the most probable intersegmental distance as measured by WAXS; in both cases, with an exponential coefficient that depends on the kinetic gas diameter as a quadratic polynomial and with a preexponential positive constant. Moreover, it has been proven that the intersegmental distance increases linearly with the free volume fraction. Finally, it has been established that the free volume fraction increases with the glass transition temperature for the polymers tested, and that they depend on each other in an approximate linear way. PB MDPI SN 2073-4360 YR 2023 FD 2023 LK https://uvadoc.uva.es/handle/10324/67189 UL https://uvadoc.uva.es/handle/10324/67189 LA eng NO Polymers, 2024, Vol. 16, Nº. 1, 13 NO Producción Científica DS UVaDOC RD 17-may-2024