(292d) Engineering Polymeric Hollow Fiber Contactors for Separation and Reaction Applications

There are three objectives regarding the advancement of composite polymer hollow fibers for separation and reaction: (i) fabrication of polyamide-imide hollow fiber (PAI-HF) support with engineered surface porosity. A new approach for formation of a thin selective layer of phosphazene (MEEP) and polydimethylsiloxane (PDMS) intermediate layers on PAI-HF support was developed on the as-spun fibers without the need to undergo the final conventional solvent exchange and drying steps, thereby saving post-spinning processing steps. The effect of coating solution, re-wetting and crosslinking temperature, physical aging, moisture and fouling on the MEEP/PDMS/PAI-HFs features e.g. gas transport, skin thickness, skin integrity, and substructure resistance were investigated. The produced MEEP/PDMS/PAI-HF composites were used for CO₂/N₂ separation. (ii) creation of polymeric hollow fiber sorbents consisting of PAI polymer and silica particles by an in-situ process. This approach resulted in silica/polymer composite fibers with good amine distribution and accessibility after infusion with aminosilane, as well as adequate porosity. Moreover, the in-situ formed particles appear to be firmly retained within the fibers and enable rapid mass transfer and adsorption kinetics. Therefore, this process offers a low-cost method of fabricating and engineering the amine/silica/polymer hollow fiber sorbents with high equilibrium capacity for postcombustion CO₂ capture. (iii) development of a proof-of-concept study for a new type of microfluidic reactors based on porous PAI composite hollow fibers. These novel hollow fiber microfluidic reactors consist of bifunctional groups in the fiber wall that make them bifunctional catalysts for cooperative interactions (i.e., acid-base catalysis). Based on the optimized conditions for aldol and nitroaldol condensations, Heck coupling and CO₂ cycloaddition reactions, we identified a robust process window to produce composite hollow fiber microfluidic reactors for sustainable C-H functionalization and CO₂ utilization system in flow.