UV irradiation-assisted cross-linking of high molecular weight poly (ethylene oxide) with poly (ethylene glycol) diacrylate to prepare CO2 selective membranes

In this work, the high molecular weight poly (ethylene oxide) (PEO) was cross-linked under UV irradiation to decrease its crystallinity in order to prepare a high-performance CO2-selective membrane. Poly (ethylene glycol) diacrylate (PEGDA) containing CO2-philic ether oxygen group was used as both photo-initiator and cross-linking agent. It was found that the crystallinity degree from 82.4% for the neat PEO membrane decreased to 65.4% for the cross-linked PEO membrane by the proposed cross-linking technique. The observations indicated that the structural and gas separation properties of the cross-linked PEO membranes strongly depend on the PEGDA concentration and UV irradiation time. When the PEGDA concentration was between 3 and 7 %wt and at UV irradiation time of 30 min, the prepared membrane overcame Robeson upper bound and indicated a fairly good separation performance in the case of CO2 separation from N2, compared to the similar cross-linked PEG-based membranes in the literature.