High-efficiency mechanical reinforcement of energetic polymer composites via synergistic modification of particle surface and binder components

Sufficient interfacial interactions and strength are crucial for ensuring the mechanical integrity of energetic polymer composites. However, weak interfacial interactions persistently restrict and weaken the mechanical performance, and efficiently enhancing these interactions still remains highly challenging. Herein, we reported a bidirectional enhancement strategy based on synergistic modifications of explosive particle surfaces and binder functionalization. First, rapid spontaneous polymerization coating of 4-aminostyrene (4-AS) was applied to 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) surfaces in an acidic polyanion aqueous solution initiated by zwitterions, achieving instantaneous robust adhesion with TATB. The abundant functional groups in the coating provided strong, multiple interfacial interactions with the binder. Second, concurrently, an inert fluoropolymer (FP) binder with excellent comprehensive properties was functionalized by grafting hydroxyl and ester groups onto its side chains, further enhancing binder-explosive interfacial interactions. The resultant interface with TATB coating and fluoropolymer functionalization exhibited robust, high-strength adhesion compared to pristine TATB/FP systems. Consequently, optimally modified composites demonstrated 80% and 66% enhancements in tensile and compressive strength, respectively, while fracture energies (representing toughness) increased significantly by 172% (tensile) and 294% (compressive). This work provides new insights for designing novel and universal interfacial structures in composites, demonstrating promising potential for high-performance polymer composites.