Investigation of neutron shielding performance of epoxy composites: showcasing the theoretical predictions of epoxy composites with graphene and hexagonal boron nitride fillers

Lightweight polymer matrix composites are attractive for neutron shielding since hydrogen-rich epoxy resins provide strong moderation of fast neutrons. This work evaluates theoretical neutron transport properties of epoxy composites with graphene (GNP) and hexagonal boron nitride (hBN) fillers. Rule-of-mixtures densities were calculated: neat epoxy is 1.15 gcm−3, epoxy plus 1–3 wt% GNP are ≈1.15–1.16 gcm−3, while hybrids with 9–27 wt% hBN (plus 1–3 wt% GNP) range ≈1.19–1.33 gcm−3. Fast neutron removal cross sections (ΣR) and moderation power (MP) both decrease slightly with GNP loading, indicating moderation than neat epoxy. Thermal neutron absorption (1/e depth) is essentially unchanged or slightly increased by pure GNP (163–165 cm vs 163 cm for epoxy), confirming carbon’s negligible capture ability. In contrast, hBN-GNP hybrids exhibit dramatically enhanced thermal absorption: 1/e depths drop to ≈0.17–0.55 cm and total cross sections rise to ∼2.5–6.7 cm−1 (neat epoxy ≈0.67 cm−1). These changes are dominated by 10B in hBN. These analyses show that epoxy plus GNP composites do not improve neutron shielding, whereas epoxy along with hBN plus GNP hybrids provide excellent thermal neutron attenuation (through 10B capture) along with modest density increases (up to ∼1.33 gcm−3). The results underscore GNP’s limited role in shielding and hBN’s key role as a neutron absorber.