Preparation and property of epoxy resins-penetrated aligned carbon nanotube bundle hybrid microcapsules for self-healing polymers

The epoxy resins-penetrated aligned carbon nanotube bundle (ACNTsB) hybrid system (epoxy@ACNTsB) was prepared by soaking ACNTsB in the acetone solution of epoxy resins. Epoxy@ACNTsB was encapsulated in aqueous solution containing an amine curing agent to prepare hybrid microcapsules (MCs). The structure and morphology of MCs were characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, and laser scanning confocal microscopy. The thermal properties of MCs were carried out by differential scanning calorimetry and thermogravimetric analysis. The solvent resistance of MCs in acetone was also investigated. The results show that MCs exhibit high initial decomposition of temperatures (266 degrees C). The content of epoxy resin in MCs is about 74% and the polymer film thickness of MCs is from 1 to 2 m. MCs show high thermal and chemical stability below 200 degrees C and excellent solvent resistance. MCs embedded in cyanate ester (CE) resins can significantly toughen the matrix. The fracture MCs can release the epoxy resins under heating condition, and the released epoxy resins can react with the reactive -OCN group/triazine rings in the CE matrix to rebond the crack surfaces. When the temperature schedule of 100 degrees C/1 h + 200 degrees C/2 h is applied, 10-15 wt% MCs can recover from 82.7% to 99.8% of the original fracture toughness of CE matrix.