Ultra-high mechanical property and interface enhancement of PBX energetic composites based on hydrogen bond cross-linked network

The poor bonding of fluoropolymers had indeed affected the mechanical performance of explosive composite. Herein, two types of polythiourea (PT) binders with lined and crosslinking structures were utilized in polymer bonded explosives (PBXs). PT binders were uniformly coated on 2,4,6-trinitrobenzene-1,3,5-triamine (TATB), confirmed by the homogeneous distribution of sulfur (S) element in the molding powder. For creep resistance, PBX-PT-4 exhibited strain below 0.0006 at 60 °C and storage modulus of 6295 MPa at room temperature. Moreover, the mechanical properties showed that PBX-PT-2 possessed the maximum tensile strength of 10.49 MPa, which was about 54.7% enhancement than that of PBX-0. PBX-PT-2 and PBX-PT-4, owning entangled polymer chains, reached the maximum fracture energy with values of W b and W c increased by 205.3% and 93.8%, respectively. Meanwhile, structural characterization and simulation for PT-4 and PBX-PT-4 presented the fracture resistance and enhanced interfacial adhesion with TATB via intermolecular hydrogen bond, which effectively contributed to the remarkable improvement in mechanical properties. By using cross-linked PT as binders demonstrated in this study provided a important strategy for the design of PBXs and facilitated the achievement of ultra-high mechanical properties in composites.