Microencapsulation of a Reactive Liquid-Phase Amine for Self-Healing Epoxy Composites

A method was developed for the preparation of microcapsules containing a reactive amine with potential applications in self-healing polymers. Airline core microcapsules were prepared by interfacial polymerization of an isocyanate and an amine stabilized by an inverse Pickering emulsion. Microcapsules were successfully isolated, dried, and redispersed in epoxy. Visualization of capsules in cured epoxy was carried out by the addition of fluorescent dye to the core material. Mass spectrometry of capsule core material indicated the presence of the desired starting material. Fill content was estimated at 55 wt% by thermogravimetric analysis, and titration of the capsule core material gave an amine equivalent weight of 254 g/mol NH2. Capsules released the core material upon rupture and were able to cure epoxy to form a polymer film.