CO2 induced plasticization in glassy polymeric membranes for gas separation
| Autor: | Stefano Oradei, Matteo Minelli, Maurizio Fiorini, Giulio Cesare Sarti |
|---|---|
| Přispěvatelé: | Minelli, M.,Oradei, S., Fiorini, M., Sarti, G.C. |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
gas permeability Dynamic Mechanical Analysi Materials science Relaxation (NMR) gas separation membrane Polymer Thermal diffusivity Glassy polymers Membrane chemistry Permeability (electromagnetism) CO2 plasticization Gas separation Composite material Glass transition Elastic modulus |
| Popis: | In gas separation membrane processes, CO2 may induce the plasticization of glassy polymer, lowering its the mechanical rigidity and reducing the glass transition, with a loss of separation performances. Such mechanism is often associated to gas permeability behavior in glassy membranes vs. upstream p, and increasing trends are considered as the footprint of the plasticization onset. However, there is no clear correlation between gas permeability and the effects of CO2 on mechanical behavior. The CO2 induced plasticization in glassy membranes is investigated by direct DMA analysis of polymers saturated at different CO2 pressures. Matrimid polyimide is considered, as it shows a non-monotonous CO2 permeability behavior, and compared to PS (decreasing behavior) and PMMA (increasing).CO2 lowed the elastic modulus of all materials investigated, while the relaxation dynamics revealed a strong enhancement of tan δ, even in absence of a second order transition. The same qualitative behaviors are observed for all glassy systems investigated, and in Matrimid, no apparent change is identified around the pressure value corresponding to the minimum in CO2 permeability, excluding the presence of a new phenomenon onset. Results suggest that increasing permeability behaviors and non-monotonous trends, are not directly related to softening effect induced by CO2 in the polymer matrix, and such features have to be ascribed to the combination of solubility and diffusivity coefficients.In gas separation membrane processes, CO2 may induce the plasticization of glassy polymer, lowering its the mechanical rigidity and reducing the glass transition, with a loss of separation performances. Such mechanism is often associated to gas permeability behavior in glassy membranes vs. upstream p, and increasing trends are considered as the footprint of the plasticization onset. However, there is no clear correlation between gas permeability and the effects of CO2 on mechanical behavior. The CO2 induced plasticization in glassy membranes is investigated by direct DMA analysis of polymers saturated at different CO2 pressures. Matrimid polyimide is considered, as it shows a non-monotonous CO2 permeability behavior, and compared to PS (decreasing behavior) and PMMA (increasing).CO2 lowed the elastic modulus of all materials investigated, while the relaxation dynamics revealed a strong enhancement of tan δ, even in absence of a second order transition. The same qualitative behaviors are observed for all g... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|