Improve the gas-barrier and mechanical performance of epoxy resin by Co-modification from montmorillonite and polyethylene glycol

Type V linerless vessel can be used to store liquid hydrogen, which is made up of all-composites. But the epoxy resin matrix at this low temperature still has some issues in gas-barrier and mechanical performance. In this work, co-modification by the gas-barrier modifier of montmorillonite (MMT) and the mechanical modifier of polyethylene glycol (PEG) was performed. The experimental data demonstrated that adding 25 wt.% MMT could decrease the permeability coefficient to 0.974 × 10−15 mol/(m·s·Pa), which meets the requirements of hydrogen liner. However, adding MMT resulted in the decrease of mechanical strength at cryogenic temperature. Then, PEG was selected to improve the cryogenic toughening. Adding 10 wt.% PEG could increase the cryogenic tensile strength by 98.12%. In the meantime, it has slightly influence on the gas permeability. Compared with purely MMT modified, the permeability coefficient of samples co-modified by 25 wt.% MMT and 10 wt.% PEG was increased by 3.59%. After this co-modification, the epoxy resin was more qualified for the manufacturing of liquid hydrogen storage.