Reinforcing effect of trifluoromethyl/amino-modified neutral polymeric bonding agents on interfacial bonding of fluoropolymer/nitramine energetic composites-based high-energy polymer bonded explosives

Abstract The interfacial de-wetting problem of fluoropolymer/nitramine energetic composites such as F2313/RDX severely restricts their potentially extensive application as high-energy polymer bonded explosives (PBXs). The matched neutral polymeric bonding agents (NPBAs) can bridge the gap between the composite components and play a critical role in strengthening the composite interface to inhibit de-wetting. In this contribution, following the typical NBPA design strategy, two novel NPBAs with trifluoromethyl and amino pendants were prepared from methyl acrylate (MA), hydroxyethyl acrylate (HEA), trifluoroethyl methacrylate (TFEMA) and acrylamide (AM) as raw materials, under the action of initiator AIBN, named NPBA-2 and NPBA-3, respectively. The structure, interfacial characteristics, and bonding properties of the synthesized NPBAs were investigated. The results showed that the additional functional groups reduced the surface tension for interface wetting and effectively enhanced the bonding effect of NPBAs on F2313/RDX according to the “like-dissolves-like” rule and the formation of hydrogen bonds. The bonding properties of both novel NPBAs out-performed the control NPBA-1 and provided at least 184% interfacial reinforcement for F2313/RDX. The NPBA-2 bonded F2313/RDX energetic composite exhibited the best mechanical properties with a maximum Brazilian strength of 6.88 ± 0.02 MPa and the corresponding modulus of 10.71 ± 0.02 GPa. We believe that these NPBAs will have great application potential in high-energy PBXs. Graphical abstract