Mechanochemical Engineered Sulfur Copolymers Onto Group 13 and Related Fillers Through Lewis Acid‐Base Pairing

ABSTRACT Group 13 and related fillers are cornerstone components for advanced composites, yet their severe interfacial incompatibility with organic matrices inherently limits their practical efficacy. Conventional surface modification strategies remain fundamentally constrained by a heavy reliance on hazardous solvents, matrix curing inhibition, and structural degradation of the fillers. Herein, we report a solvent‐free mechanochemical copolymerization strategy that establishes an universal, non‐destructive interfacial engineering paradigm for diverse Group 13 and related fillers (nano‐Al, B 4 C, and ZrB 2 ). By directly architecting sulfur‐containing polymer coatings on filler surfaces, this approach elegantly exploits intrinsic Lewis acid–base pairing between electron‐deficient metal/metalloid sites and electron‐rich sulfur moieties. Mechanistically, the resulting electronic configurations and coordination chemistry are systematically elucidated via a synergistic combination of XPS, solid‐state 11 B NMR, and DFT calculations, confirming the formation of robust S–Al and S–B coordinative networks. The extraordinary universality of this matrix‐agnostic platform is validated by incredible performance increments across three distinct frontiers, driving a staggering 666% surge in combustion enthalpy for nano‐Al fuels, a 33% ablation reduction for ZrB 2 thermal shields, and concurrent ∼270% elevations in both strength and toughness for B 4 C structural composites. Ultimately, this environmentally benign protocol paves a versatile avenue toward the green synthesis of high‐performance hybrids.