Stabilization of Gas Transport Properties of Composite Membranes with a Thin PTMSP Selective Layer by Adding Porous Aromatic Framework Nanoparticles and Simultaneous Polymer Crosslinking

Abstract

Composite membranes with a thin selective layer based on poly[1-trimethylsilyl-1-propyne] (PTMSP) and crosslinked PTMSP containing 10 wt % of nanoparticles of porous aromatic frameworks (PAF-11) have been synthesized and studied. Monitoring of changes in the gas transport characteristics of the membranes under ambient conditions for 7500 h has revealed that for all the samples, the transport characteristics abruptly decrease within the first 1000–2000 h; after that, the mass transfer constants gradually change over time. In the case of a composite membrane with the selective layer based on crosslinked PTMSP and PAF-11 nanoparticles, stable permeability values after 7000 h are 2.1, 3.5, and 12.9 m³/(m² h atm) for N₂, O₂, and CO₂,respectively (at an ideal selectivity of α(O₂/N₂) = 1.6 and α(CO₂/N₂) = 6.1); to date, this is the best published result for thin-film composite membranes based on highly permeable glassy polymers.