New crosslinking method of polyamide-imide membranes for potential application in harsh polar aprotic solvents

We report for the first time successful crosslinking of polyamide–imide (Torlon®) based membranes using di-isocyanates. The crosslinked membranes are resistant to N-methyl pyrrolidone (which is solvent of the non-crosslinked membranes) and have very good mechanical properties. In contrast to the state-of-the-art polyimide crosslinked membranes, the created covalent bond is expected to be thermally stable enabling applications at elevated temperatures. The transport characteristics (permeance and molecular weight cut off – MWCO) of the crosslinked membranes are changed in comparison to non-crosslinked ones. This suggests that the crosslinking process could be used to tailor these characteristics