Facilitated olefin transport through membranes consisting of partially polarized silver nanoparticles and PEMA-g-PPG graft copolymer

We report the preparation of solid-state facilitated olefin transport membranes based on a low-cost, one-pot, room-temperature synthesized graft copolymer, i.e., poly(ethylene-alt-maleic anhydride)-g-O-(2-aminopropyl)-O'-(2-methoxyethyl) polypropylene glycol (PEMA-g-PPG). An electron acceptor, 7,7,8,8-tetracyanoquinodimethane (TCNQ), was employed to activate the surface of the silver nanoparticles (AgNPs), leading to partial polarization. The AgNPs interacted with TCNQ as well as the PEMA-g-PPG graft copolymer to form facilitated olefin transport membranes, as characterized by Fourier transform infrared spectroscopy, UV-vis spectroscopy, and X-ray photoelectron spectroscopy. The PEMA-g-PPG/AgNP membrane activated by TCNQ showed long-term stability (with a mixed gas permeance of 7.8 GPU and propylene/propane selectivity of 17.5) of up to 100 h, while that without TCNQ showed poor stability. The membrane based on PEMA-g-PPG showed better performance than those based on conventional matrices of poly(ethylene oxide) (PEO), poly(vinyl pyrrolidone) (PVP), or poly(ether-block-amide) (PEBAX).