Incorporating COFs into PDMS matrix for accelerated crosslinking and efficient ethanol recovery

Mixed matrix membranes are attracting increasing attention due to their potential to provide selective channels in the polymer matrix. However, the compatibility and dispersion of nanoparticles in organic polymers are still challenging in membrane preparation procedure. Covalent organic frameworks (COFs) are excellent nano-fillers due to their good compatibility with organic polymers. In this work, LZU8 particles were incorporated into polydimethylsiloxane (PDMS) membranes. SEM observations showed that the LZU8 particles were well dispersed in the PDMS matrix. Additionally, the viscosity changes of membrane solution and the LF-NMR result of the crosslinked membranes showed that the incorporation of LZU8 could accelerate the crosslinking of the PDMS solution. The LZU8-PDMS membrane was applied for the pervaporation of 5 wt% ethanol/water solution, which exhibited a high flux of 5 kg m2·h-1 and a separation factor of 11. Considering the compatibility of inorganic particles with polymer and the controlling of crosslinking could be critical factors in mixed matrix membranes fabrication procedure, this LZU8 can be a promising nano-filler for improving the performance of membranes.