Phthalonitrile resin reinforced silane surface modified boron carbide: Efficient neutrons screening and exceptional thermal properties

Abstract

The design of lightweight neutron shields has been restricted for quite some time to the use of epoxy thermosets as the main building blocks. Meanwhile, the recent developments in the field of polymers suggest otherwise. Indeed, the phthalonitrile (PN) resins have taken the lead over traditional thermosets in many demanding applications. Therefore, in a vision to introduce newer matrices with better performances and to further expand the applications of the PN resins into the nuclear field, the neutron shielding efficiency along with the thermal resistance performances of the neat PN polymer and its subsequent silane surface-modified B₄C-reinforced composites were investigated. The neutron shielding measurements were performed using an optimized experimental setup at the NUR research reactor in Algiers. The neat PN polymer displayed better thermal neutron screening performances than the epoxy and benzoxazine, with a macroscopic cross-section (Σ) of a 1.936 cm⁻¹, equivalent to a mean free path (λ) of 0.358 cm. The effect of the particle amount was also studied to maximize the shielding ability of the developed materials. For instance, the PN composite containing 20 wt. % of B₄C displayed an outstanding screening ratio of about 99.8% for a sample thickness of 13 mm. Finally, the remarkable findings were put into context by providing multifaceted comparisons with the available shielding materials.