Tailoring the molecular sieving properties and thermal stability of carbonized membranes containing polyhedral oligomeric silsesquioxane (POSS)-polyimide via the introduction of norbornene

摘要: Abstract Two types of POSS (polyhedral oligomeric silsesquioxane)-polymers, (POSS-polyimide-phenyl (POSS-PI-Ph) and POSS-polyimide-phenyl-norbornene (POSS-PI-Ph-Norbornene)), were utilized for the fabrication highly permeable gas-separation membranes. POSS-PI-Ph POSS-PI-Ph-Norbornene separation layer selective gas successfully formed on porous intermediate layer. A POSS-derived membrane calcined at 250–350 °C under N2 showed approximately same levels selectivity He/N2 CO2/N2 as conventional polyimide membranes, which shows there was no formation large pores that decreases selectivity. The introduction norbornene, forms a cross-linked structure by thermally inducing cross-linking 500 °C N2, improved permeance without decreasing gas-permeance ratio. heat treated increases in He ranged from 1.2 × 10−7 to 4.6 × 10−7 mol m−2 s−1 Pa−1 with He/N2, CO2/N2, He/CF4, He/SF6 ratios 38; 8; 2700; 14000, respectively. relationship between activation energy H2 permeation He/H2 ratio POSS-derived, organosilica, polymer (polyimide, polyamide, polysulfone) membranes suggests properties depend concentration organic groups (C/Si ratio) networks, because networks become more flexible when carbon dominates properties, corresponds solution-diffusion mechanism.