Boron carbide reinforced electrospun nanocomposite fiber mats for radiation shielding

In this study, 1 wt% boron carbide (B₄C) reinforced PVA nanofibers were fabricated by the electrospinning technique as a new generation of ultra-thin, lightweight, and flexible neutron shielding nanocomposites. The influence of B₄C particles' size and morphology on the fiber formation and radiation shielding performance of fiber mats was investigated. The results indicate that the particle characteristics have a dramatic influence on the formation and properties of nanocomposites. The thicknesses of individual fibers reinforced with sol–gel synthesized nano-sized boron carbide particles were in the range of 50–250 nm, while those containing commercial B₄C powder were produced in the thickness range of 1–2 μm. In contrast to the commercial particles, the sol–gel synthesized nano B₄C particles enhanced the fiber mat's density and the roundness of individual fibers. Both theoretical and experimental radiation shielding studies showed that B₄C reinforcement successfully improved the neutron and gamma attenuation of the neat PVA matrix. Furthermore, it was found that a 6.5 mm thick PVA nanofiber mat, reinforced with only 1 wt% B₄C nanoparticles shielded up to about 7.4% of the initial neutron flux. Compared to the neat PVA fiber mat, reinforcement of PVA fibers with 1 wt% sol–gel synthesized nano-sized boron carbide particles enhanced the neutron shielding by 50.31%. Moreover, even though B₄C is not an effective gamma shielding reinforcement, the amplified density of nanocomposite fiber mats also enhanced gamma attenuation.