Advances in the design of co-poly(ether-imide) membranes for CO2 separations. Influence of aromatic rigidity on crystallinity, phase segregation and gas transport

Abstract

SummaryIn our previous works, it was observed a clear relationship between the structure and the properties for different copoly(ether-imide)s, besides a good relation was found between SAXS characterization and permeability results. Here, a series of aliphatic aromatic copoly(ether-imide)s, based on an aromatic diamine (ODA), a diamine terminated poly(ethylene oxide) (PEO2000) of a molecular weight of 2000 g/mol and different aromatic dianhydrides (BPDA, BKDA (or BTDA) and PMDA )has been synthesized and characterized.The permeability for O2, N2, CO2 and CH4, increased with the rigidity of the monomers (BKDA < BPDA < PMDA), with the amount of PEO2000 in the copolymers, as well as with the increase in the temperature of treatment of the films. In this case, it was observed that when the proportion of PEO in the copolymer exceeded 50%, the permeability was similar for all samples, and the aromatic portion had no significant influence.Attending to glass transition temperature, Tg, of the aliphatic part, to its melting temperature, Tm, and to its crystallinity, segregation was better for more rigid dianhydrides at lower temperatures of treatment. Higher dianhydride rigidity produced better mechanical properties that were good but decreased a little bit when the percentage of PEO in the samples increased.Good permeselectivity compromises were attained for the CO2/N2 separation .This work gives light to design advanced materials for this separation with the increasing possibilities of controled structure and properties.

Highly cross-linked polyether-based 1,2,3-triazolium ion conducting membranes with enhanced gas separation properties

“…PEG-based polymeric membranes present potentials for CO 2 separation as they have high affinity towards CO 2 due to the ether segments. [30][31][32][33][34][35][36][37][38][39][40] However, they suffer from high crystallinity and weak mechanical strength. [41] PTMEG is a commercially available starting material derived from renewable resources that is more hydrophobic than PEG.…”

Advances in high carbon dioxide separation performance of poly (ethylene oxide)-based membranes

“…Among glassy polymers, aromatic polyimides (PIs) are appealing materials in the view of fabricating gas separation membranes, due to their excellent gas permeability and good selectivity, and their good physico-chemical properties [11 , 58-62] . For example, PEO/polyimide has a high permeability and a high selectivity for CO 2 separation [63][64][65] . Copolyimides containing ethylene oxide have a higher diffusivity for CO 2 and N 2 than pure polyimides.…”

Elimination of the Crystallinity of Long Polyethylene Oxide‐Based Copolymers for Gas Separation Membranes by Using Electron Beam Irradiation

“…The combination of PEO chains with poly(propylene oxide), poly(dimethyl siloxane),or other alkyl groups have proved to reduce crystallinity and increase permeability in the polymers. When PEO is copolymerized with other monomers that react to form rigid segments (aromatic polyimide segments, for example), a high selectivity is obtained, almost regardless of the composition of the rigid segments . With respect to the permeability, several parameters have been studied, and it was found that the main parameters were the content and the chain length of the PEO segments in the polymer .…”