Fabrication of epoxy resin reinforced polyimide (PI) nanofibrous membrane

•A pathway to fabricate epoxy resin reinforced e-spun PI membrane was suggested.•The strength of the reinforced membrane was 4 times that of the pristine one.•It kept the excellent filtration without significant increase of pressure drop.•It was not fuzzing and had strong adhesion with substrate. Electrospinning is an emerging technique to fabricate nanofibrous nonwoven membranes, but the weak mechanical strength of electrospun products is blocking their applications. In this research, the PI nanofibrous nonwoven membranes were afforded via electrospinning and reinforced by facilely dipping into a diluted epoxy resin solution. There was fusion of fibers at the points of contact or cross among them, which provided about 4 times stronger strength than that of pristine PI ones and higher elongation at break. Furthermore, the epoxy reinforced PI membrane was not fuzzing and had strong adhesion to substrates. They exhibited good filtration efficiency and did not increase pressure-drop overwhelmingly although the average pore size reduced. This research suggested a feasible strategy to fabricate epoxy resin reinforced nanofibrous membranes, which would be promising applications in air filtration, battery’s separator, water treatment etc.