High-Performance Self-Cross-Linked PGP–POEM Comb Copolymer Membranes for CO2 Capture

5 years ago

High-Performance Self-Cross-Linked PGP–POEM Comb Copolymer Membranes for CO2 Capture

Na Un Kim, Jong Hak Kim, Yeji Choi, Byeong Ju Park, Ki Bong Lee

We report a high performance CO₂ capture membrane based on the copolymerization and self-cross-linking of poly(glycidyl methacrylate-g-poly(propylene glycol))-co-poly(oxyethylene methacrylate) (PGP–POEM) comb copolymer. The epoxide–amine reaction is responsible for the self-cross-linking reaction, which takes place under mild conditions without any additional cross-linkers or catalysts. The effects of self-cross-linking on the membrane properties are investigated by comparing the copolymers with those containing a low PPG grafting density (l-PGP–POEM). Furthermore, the gas separation performance of the membranes is systematically investigated as a function of POEM content in the comb copolymer. Both the permeance and selectivity of the PGP–POEM membranes are enhanced simultaneously with increase in the POEM content up to 51.2 wt % (PGP–POEM13), at which the best performance was achieved among the membranes. The high performance results from the reduced diffusion of N₂ due to the self-cross-linked structure as well as the increased CO₂ solubility due to the high content of ether oxygen groups in the comb copolymer. By optimizing the membrane thickness, the performance is further improved up to a CO₂ permeance of 500 GPU (1 GPU = 10^–6 cm³ (STP)/(s cm² cmHg)) and CO₂/N₂ selectivity of 22.4, which is close to the commercialization target area of CO₂ capture membranes. This work suggests a simple and economical cross-linking method to fabricate the membranes with excellent gas separation performance.

Publisher URL: http://dx.doi.org/10.1021/acs.macromol.7b02024

DOI: 10.1021/acs.macromol.7b02024