Investigation of atomic oxygen resistance improving mechanism for epoxy/silica nanocomposites

To improve the atomic oxygen (AO) resistance of the spacecraft resin matrix material, the inorganic silica nanoparticles are filled into the epoxy resin. Samples of the epoxy/silica nanocomposites are prepared and the AO exposure experiments are conducted in a ground-based AO effect simulation facility. The samples exhibites significantly less mass loss and erosion yield than the corresponding pristine epoxy resin. After AO exposure for 60 h, the erosion yield of the nanocomposite containing 15 phr nanoparticles decreases to 9.4% of that of the pristine epoxy resin. Analyses of the surface morphology, surface compositions and surface chemical structures show that after the AO exposure experiment some organic structures still resides on the nanocomposites surfaces besides the nanoparticles. The organic structures are nonreactive with AO. The silica nanoparticles and the organic structures can serve as a barrier to resist further erosion.