Nano-modified epoxy resins as space radiation shielding materials

Abstract

Space radiation has become one of the major factors for limiting space mission duration because of the effects of radiation exposure on astronauts, electronics and materials. A recent thrust to minimize exposure to space radiation has made researchers turn to nanomaterial additives. These new nanomaterials propose an elegant solution to enhancing composites characterized and utilized in qualified space structures. In this paper we look at two distinct nanomaterials, Boron Nitride Nanoparticles (BNPs) and Boron Nitride Nanotubes (BNNTs). Boron nitride materials were selected based on four properties: BNNTs are good structural materials; B10has a large neutron capture cross-section for radiation shielding; boron and nitrogen are lightweight elements; and finally, asymmetric charge distribution between nitrogen and boron promotes good interfacial compatibility between the nanomaterial and resin system. Two phase composites, made up of an Epon 862/"W" epoxy resin matrix and nanomaterials (BNPs or BNNTs), were created containing three different percentages of additives, 0.15%, 0.0825%, and 0.015% by weight. These loading percentages were chosen to maintain a resin viscosity that allows for the nano-modified resin to be applicable in conventional composite processing methods, such as, Vacuum Assisted Resin Transfer Molding (VARTM) or Heated Vacuum Assisted Resin Transfer Molding (HVARTM). Also, these concentrations were chosen due to percolation density limits of CNTs and to create a preliminary understanding of the interaction between the BNNTs and Epon 862/W resin system. Thus, the focus of this study is to understand the effects of the radiation shielding nanomaterial, BNNTs, on the mechanical and thermal properties of the Epon 862/W resin system. Specifically, the mechanical and thermal properties, such as tensile strength and glass transition temperature, were examined for these nano-modified resins. While it is expected that adding non-functionalized nanomaterials to polymeric composites leads to matrix mechanical properties degradation, the results showed no significant degradation in mechanical strength. These new nano-modified composites demonstrate good homogeneity and equivalent or improved mechanical and thermal properties. Copyright 2014. Used by the Society of the Advancement of Material and Process Engineering with permission.