Practicable self‐healing polyurethane binder for energetic composites combining thermo‐reversible DA action and shape‐memory effect

Abstract

A novel thermally mendable polyurethane binder for energetic composites was designed and prepared via the Diels‐Alder (DA) cycloaddition reaction between a furan functionalized polycaprolactone (PCL) prepolymer and a bismaleimide compound. The structures and properties of synthesized PCL‐DA‐PU were fully characterized via Proton Nuclear Magnetic Resonance (1H‐NMR) and Fourier Transform Infrared spectroscopy (FT‐IR), Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) measurements. As‐prepared material showed good self‐healing ability of scratches by virtue of combining the shape recovery effect of PCL segments favoring scratch closure with the re‐crosslinking of the cleaved DA bonds, which was evidenced by optical microscopy and tensile analysis. A scratch healing efficiency determined by tensile tests of about 89% was achieved. Moreover, with the contribution of DA bonds in PCL‐DA‐PU binder, the microcracks and other damages in the TATB based energetic composites were almost mended and the mechanical strength can recovery above 78%.

Enhanced Shape Memory Metal-Coordinated Poly(aryl ether ketone)s with Tunable Gradient-Deformation Behaviors as well as Self-Healing and Reprocessing Abilities

“…Rigid regions, composed of rigid segments, chain entanglements, crystalline phases, and crosslinking points, are involved in the structural stability and recovery of permanent shape. − Programable deformation ability allows SMPs to be widely used in fields, such as biomedical tissues, smart actuators, electronic devices, and aerospace structures, − which could be triggered by diverse external stimuli, including heat, light, electricity, magnetic field, and solvent . Nevertheless, SMPs, such as polylactic acid, − polyurethane, − and polycaprolactone, − with excellent self-deformation ability, usually exhibit the weak mechanical performances and poor thermal stability, which restrict their applications in engineering structures. Therefore, a SMP with both good mechanical properties and outstanding shape memory ability has attracted much attention and increasingly become the research hotspot.…”

Self‐Healing Polybutadienes Formed through Sigmatropic Rearrangement and Stratified H‐Bonding for Use in Polymer‐Bonded Explosives

“…Self‐healing in polymer bonded explosive systems are investigated widely and has been accomplished by various intrinsic healing mechanisms. Diels‐Alder reaction based self‐healing in polyurethane based explosive formulations were reported by Yubin Li et al and Min Xia et al separately [36–38] . Self‐healing enabled by dynamic disulphide bonds in PBX binder matrices were reported in polycaprolactone polyurethanes and in energetic thermoplastic elastomers [39,40] .…”

Thermoplastic vulcanizates dynamically cross‐linked by a tailored small molecule

“…5 On the other hand, inspired by nature, some new bionic structures and materials are gradually developed. 6,7 Intense effort has been devoted to incorporating elegant dynamic reversible bonds into cross-linked polymer networks, such as with Diels-Alder bonds, 8,9 metal-ligand coordination, 10 disulfides, 11,12 hydrogen bonds, 13 imine bonds, 14,15 π-π stacking, 16 boronic ester bonds, [17][18][19] and so on. When changing environment, such as temperature, 20,21 light, 22,23 electrical current injection, 24 and other factors, these types of supramolecular chemical bonds can be reversibly broken and reorganized, thus the material is expected to become repairable and plasticizable.…”