NANO-MODIFIED EPOXY RESINS AS SPACE RADIATION SHIELDING MATERIALS

摘要

Space radiation has become one of the major factors for limiting space mission duration becausernof the effects of radiation exposure on astronauts, electronics and materials. A recent thrust tornminimize exposure to space radiation has made researchers turn to nanomaterial additives. Thesernnew nanomaterials propose an elegant solution to enhancing composites characterized andrnutilized in qualified space structures. In this paper we look at two distinct nanomaterials, BoronrnNitride Nanoparticles (BNPs) and Boron Nitride Nanotubes (BNNTs). Boron nitride materialsrnwere selected based on four properties: BNNTs are good structural materials; B~(10) has a largernneutron capture cross-section for radiation shielding; boron and nitrogen are lightweightrnelements; and finally, asymmetric charge distribution between nitrogen and boron promotes goodrninterfacial compatibility between the nanomaterial and resin system. Two phase composites,rnmade up of an Epon 862/”W” epoxy resin matrix and nanomaterials (BNPs or BNNTs), wererncreated containing three different percentages of additives, 0.15%, 0.0825%, and 0.015% byrnweight. These loading percentages were chosen to maintain a resin viscosity that allows for thernnano-modified resin to be applicable in conventional composite processing methods, such as,rnVacuum Assisted Resin Transfer Molding (VARTM) or Heated Vacuum Assisted ResinrnTransfer Molding (HVARTM). Also, these concentrations were chosen due to percolationrndensity limits of CNTs and to create a preliminary understanding of the interaction between thernBNNTs and Epon 862/W resin system. Thus, the focus of this study is to understand the effectsrnof the radiation shielding nanomaterial, BNNTs, on the mechanical and thermal properties of thernEpon 862/W resin system. Specifically, the mechanical and thermal properties, such as tensilernstrength and glass transition temperature, were examined for these nano-modified resins. Whilernit is expected that adding non-functionalized nanomaterials to polymeric composites leads tornmatrix mechanical properties degradation, the results showed no significant degradation inrnmechanical strength. These new nano-modified composites demonstrate good homogeneity andrnequivalent or improved mechanical and thermal properties.