Mechanical properties and liquid oxygen compatibility of nano-silica and graphene oxide modified phosphorus-containing epoxy resin

To develop an epoxy resin that can be used in composite liquid oxygen tanks, nano-silica (nano-SiO2) and graphene oxide (GO) were used to modify the physical properties of phosphorus-containing epoxy resins. The effects of nano-SiO2 and GO on the liquid-oxygen compatibility and mechanical properties of the modified resins were investigated by molecular dynamics methods, and the effects of nanoparticle size on the liquid oxygen compatibility were discussed. The simulation results show that the phosphorus-containing epoxy resin modified with 3% silica and 1% GO can effectively reduce the reaction intensity of the resins, which significantly enhance the flame retardancy and improve the liquid oxygen compatibility, and by comparing different sizes of nanoparticles, it was found that the liquid oxygen compatibility increased with their increase; Further, the modified epoxy resin maintains the original elastic modulus and yield strength, and can effectively absorb fracture energy and obtain higher fracture toughness.