Polymer materials modified with boron carbide B4C and mechanocomposite B4C/W for radiation protection in spacecraft

Composites based on ultra-high molecular weight polyethylene, modified by nanoparticles of boron carbide B4C and composite B4C/W, for protection materials against fast and slow (thermal) neutrons and γ-radiation, are formed by mechanochemical synthesis in a high-energy planetary ball mill. Their phase composition and microstructural characteristics were studied by X-ray phase analysis (D8 Advance diffractometer, Bruker), electron microscopy (scanning electron microscope CamScan 4) and infrared Fourier spectroscopy (Fourier spectrometer Nikolet iS10). The joint mechanical treatment of ultra-high molecular weight polyethylene and boron carbide B4C powders in the planetary ball mill leads to the formation of polymer composite particles of scaly shape with random distribution of boron carbide particles in them and nanocrystalline iron evenly distributed in the polymer matrix in an amount of ~ 9 wt. %. In addition, the structure of boron carbide with a lower carbon content (B6.5C) is formed, and there is a break in the molecular chains of polyethylene and its amorphization. The combined processing of ultra-high molecular weight polyethylene and mechanocomposite B4C/W in a planetary ball mill leads to the formation of polymer composite particles of flake shape with a uniform distribution of boron and tungsten carbide particles in the polymer matrix. Parameters of fine structure of boron carbide B4C are changed. As a result of the interaction between the polymer matrix and the dispersed powders of the modifier, cross-linked structures are formed and the polymer is destroyed with a decrease in its molecular weight.