Tena A.,SMAP UA UVA CSIC |
Tena A.,CSIC - Institute of Polymer Science and Technology |
Marcos-Fernandez A.,SMAP UA UVA CSIC |
Marcos-Fernandez A.,CSIC - Institute of Polymer Science and Technology |
And 12 more authors.
Industrial and Engineering Chemistry Research
Copoly(ether-imide)s formed by the reaction of an aromatic dianhydride (BPDA), an aromatic diamine (ODA), and various aliphatic diamines (PEO-2000, PPO-2000, RT-1000, pTHF-1700, and pTHF-350) have been obtained. These copolymers underwent phase segregation processes, as confirmed by small-angle X-ray scattering (SAXS), when they were thermally treated. Gas permeabilities of these materials depended on the phase separation. Thus, a linear relationship between gas permeability and increasing percentage and size of the domains of the segregated phase has been obtained. The differences in the degree of segregation have been examined for the different aliphatic diamines used in the synthesis of the copolymers. The effect of polarity, length, and structure of the chain were examined in terms of permeability for the gases O 2, N 2, CO 2, and CH 4. It has been shown that long aliphatic chains with adequate polarity and the ability to interact with and enhance the condensation of a certain gas give better materials. Improved selectivities, approaching the Robeson limit, were seen as a consequence of the thermal treatment. Also, an interesting reverse selectivity has been observed for the mixture CH 4/N 2, probably due to a combined effect of a specific interaction and an increase in solubility of CH 4 in the soft segregated portions of the copolymer. © 2012 American Chemical Society. Source