Synthesis and properties of stretched polytetrafluoroethylene–sulfonated polystyrene nanocomposite membranes

•Novel PEMs based on the stretched PTFE films and sulfonated PS were obtained.•High specific proton conductivity of the membranes up to 0.25 S cm− 1 was reached.•Methanol permeability of the composite PEMs is 1.5 times lower than that for water.•Performance of PEMFC based on the PEMs is 1.5-fold higher than that on Nafion.

Nanostructured stretched polytetrafluoroethylene–sulfonated polystyrene (strPTFE–sPS) ion-exchange membranes have been synthesized by sulfonation of the nanocomposite strPTFE-implanted PS films. The implantation of the PS (17–76 wt.%) was implemented by the thermal polymerization of styrene, which was absorbed from a styrene–divinylbenzene–toluene solution in the stretched PTFE film at 90 °C. The exchange capacity of the strPTFE–sPS membranes reaches 2.3 mmol g− 1. The proton conductivity of the water-saturated samples was 2–2.5 times higher than that of Nafion-115 and MF-4SC. It is found that the synthesized membranes have a methanol diffusion coefficient and permeability that are 1.5 times lower than those for water. Comparative laboratory tests in a hydrogen-air fuel cell at room temperature showed that the current–voltage and power characteristics of the cell with the strPTFE–sPS membrane substantially exceed those with the Nafion-115 membrane.