To provide self-healing epoxy composite with adequate heat resistance for high-performance application, we developed a novel microencapsulated epoxy/mercaptan healing agent. The key measure lies in usage of diglycidyl ether of bisphenol A (EPON 828) as the polymerizable component and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) as the catalyst. Because of the higher thermal stability of EPON 828 and lower volatility of DMP-30, the healing agent and the self-healing composite not only survive high-temperature curing and thermal exposure, but also offer satisfactory capability of autonomous properties restoration, as characterized by both fracture mechanics and fatigue tests. Especially when the operation temperature is not higher than 200 °C, the performance of the healing system is nearly independent of thermal history.

Self-healing materials should take effect immediately following crack generation in principle, but the speed of autonomic recovery of mechanical properties through either extrinsic or intrinsic healing strategy reported so far is not that fast. Mostly, a couple of hours are taken for reaching steady state or maximum healing. To accelerate the healing process, the authors of this work make use of antimony pentafluoride as instant hardener of epoxy and successfully encapsulate the highly active antimony pentafluoride-ethanol complex in terms of hollow silica spheres. Accordingly, self-healing agent based on microencapsulated antimony pentafluoride-ethanol complex and epoxy monomer is developed. Epoxy material with the embedded healant capsules can thus be healed within a few seconds, as demonstrated by impact and fatigue tests. It is believed that the outcome presented here might help to move the self-healing technique closer to practical application, especially when the engineering significance of epoxy material is concerned.

By using epoxy silane as a modifier and stabilizer, ZnO quantum dots (QDs) were synthesized by a one-step precipitation approach. The ZnO QDs acquired showed satisfactory redispersibility and exhibited strong and stable photoluminescence in both solution and dry states. When the ZnO QDs content was as high as 8 wt%, the ZnO QDs-epoxy nanocomposite was still highly transparent and luminescent. Accordingly, the ZnO QDs can be used as a luminescent material, and a cool white light emitting diode (WLED) lamp was made by encapsulating a UV chip with the nanocomposite, without traditional tricolor rare earth phosphors. Additionally, the high loading nanocomposite possessed high ultraviolet resistance, which would help to improve the lifetime of the WLED.

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