(381ak) Thermal Cross-Linking and Cyclodehydration Modifications of PI Membranes for Pervaporation Applications

Membrane is one of the critical factors for the separation efficiency of the pervaporation technology. A desirable pervaporation membrane should possess high flux, superior separation factor, and long-term chemical and mechanical stability. Common hydrophilic polymeric membrane materials have been widely used for pervaporation dehydration because of their high selectivity towards water, but they generally suffer severe swelling in the aqueous solution, leading to a poor operation stability. Alternatively, polyimide membranes have drawn more and more attentions for pervaporation applications in recent years, with their superior mechanical strength and chemical stability. Here we mainly introduce our research works on the polyimide membranes for the pervaporation dehydration in recent years, including the molecular design of membrane materials and various chemical modifications to improve their separation performance and operation stability, mainly including thermal cross-linking, chemical crosslinking and thermal cyclodehydration. Among then, thermal cyclodehydration is introduced into the hydrazide-crosslinked polyimide membranes for the first time, which incorporates aromatic oxadiazole rings into PI matrix and endows the polyimide membrane with larger d-spacing and improved solvent resistance, leading to the greatly improved separation performance and operation stability.

References

1. J. Membr. Sci. 2018, 549, 184–191.
2. Sep. Purif. Technol. 2017, 185, 215–226.
3. J. Membr. Sci. 2015, 496, 142–155.