Effects of coating solvent and thermal treatment on transport and morphological characteristics of PDMS/Torlon composite hollow fiber membrane

摘要

A new approach for formation of the polydimethylsiloxane (PDMS) layer on Torlon polyamide-imide hollow fiber (PAI-HF) support has been developed by directly after fiber spinning without the need to undergo the final conventional solvent exchange and drying step, thereby saving postspinning processing steps. The produced PDMS/PAI-HF composite membranes were found to have high CO2 permeance (i.e., 1100 GPU) and exhibited good CO2/N-2 selectivities of 8-10 which is close to 90% of that of a PDMS dense film. The effects of coating solution, rewetting and crosslinking temperature on the PAI-HF morphological features, that is, gas transport, skin thickness, skin integrity, and substructure resistance are investigated. The rewetting and thermal treatment of the PAI-HF caused the densification of the skin layer and reduced the pore sizes on the top layer. In addition, the potential use of the PAI-HF support with polymers that are insoluble in hexane is also considered. Effects of water, methanol, and hexane exposure of PAI-HF to these solvents are considered. This evaluation calls attention to issues that must be addressed in any eventual use of the PAI-HF with water-soluble or methanol-soluble selective layer polymers, rather than simple hexane-soluble polymers such as PDMS. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45418.