Crosslinking of Polybenzodioxane PIM-1 for Improving Its Stability in Aromatic Hydrocarbons

Crosslinking of polybenzodioxane PIM-1 with polyethylenimine and aluminum chloride to improve the polymer stability in aromatic hydrocarbons for its use in the processes of membrane separation of mixtures of arenes and polar solvents has been carried out and studied. Crosslinking with polyethylenimine has been realized with the use of two methods: by keeping PIM-1 films involving 4–20 wt % polyethylenimine in a poly(ethylene glycol glycidyl ether) solution or by heating. The obtained crosslinked samples have been examined using FTIR spectroscopy. It has been found that, in samples crosslinked thermally or with the use of aluminum chloride, amide crosslinks and noncovalent association are produced. The values of sorption and degree of swelling in toluene, triethylene glycol, and dimethylsulfoxide were determined for evaluating the promise of further separation of toluene–polar solvent mixtures. The optimum properties have been shown by thermally crosslinked PIM-1 films containing 16 wt % polyethylenimine and films crosslinked with aluminum chloride.