Interfacial control of B4C-filled boron geopolymers for enhanced neutron shielding

Abstract

Metakaolin-based geopolymers incorporating boron carbide (B4C) as a neutron-absorbing filler show promise for radioactive waste remediation. However, B4C’s weakly polar, negatively charged surface causes poor interfacial bonding, leading to reduced mechanical and chemical stability. In this study, cetyltrimethylammonium bromide (CTAB) was introduced to modify the B4C surface, reversing its charge and improving dispersion. Although CTAB slightly hindered metakaolin dissolution, it preferentially interacted with B4C, mitigating negative effects on geopolymerisation. CTAB also promoted gel formation in the interfacial transition zone, forming a dense, stable microstructure. The synergistic effect of B4C and CTAB enhanced interfacial bonding, mechanical strength, and neutron shielding performance, offering a viable pathway to develop multifunctional geopolymer composites for nuclear applications.