Abstract: The present invention provides a method for improving the performance of polyimide membranes as used in solvent-resistant nanofiltration. More specifically the method of the present invention allows to improve the solvent stability of the polyimide membranes to solvents or solvent mixtures that would dissolve polyimide under the conditions applied during the filtration, such as dimethylforrnamide (DMF), N-methylpyrrolidinone (NMP), dimethylacetamide (DMAC), tetrahydrofuran (THF), y-butyrolacton (GBL), dimethylsulphoxide (DMSO) and chlorinated solvents.

Abstract: The present invention provides a new composite material comprising a polymer matrix comprising dispersed molecular sieve porous particles of which at least part are hollow particles, meaning that the particles comprise a shell enclosing cavities, of which the volume is at least two times larger than the average volume of the pores comprised in the shell of such particle. The invention further relates to membranes comprising such materials as well as the use of such membranes.