Unveiling the distribution and molecular interactions of gases in membranes of PPO and PC with porous biphenyl-based knitting aryl polymer (K2Ph) and their influence on gas transport with NMR

NMR spectroscopy combined with pulsed gradient spin-echo (PGSE) NMR are used to study, at the molecular scale, the interactions and transport of pure and mixed CO 2 and CH 4 in mixed matrix membranes (MMMs) of poly(2,6-dimethyl-p-phenylene oxide) (PPO) and poly[bisphenol A carbonate- co -4,4’-(3,3,5-trimethylcyclohexylidene) diphenol carbonate] (PC) with porous biphenyl-based knitting aryl polymer (K2Ph) as filler. The results of T 1 s relaxation times and chemical shifts measurements of the sorbed gases show two populations in the MMMs associated with the polymer and filler phases. Similarly, the analysis of the gases diffusion measurements leads to two components, fast and slow tentatively assigned to the filler and polymer phases in the MMMs, respectively. The comparison of NMR results with independent measurements of total gas permeability contributes to unveil the mechanisms of gas transport in membranes of glassy PPO and PC with porous K2Ph. • Homogenous MMMs with fractions of porous K2Ph below the percolation threshold have been prepared. • The filler in the MMMs increases the gases total solubility but their permeability remains unchanged. • Multinuclear NMR spectroscopy and PGSE enable the separation and quantitation of gas transport coefficients in each phase of MMMs. • Contrasting independent measurements of transport coefficients facilitates understanding of gas transport in MMMs.