Interfacial encapsulation of bio‐based benzoxazines in epoxy shells for temperature triggered healing

Successful application of interfacial engineering for the preparation of cross‐linked epoxy microspheres containing thermally polymerizable cardanol‐based benzoxazine (Bz‐C) monomer in the core is demonstrated. Bz‐C is facilely synthesized by Mannich type condensation of cardanol (a by‐product of cashew nut industry) and aniline with formaldehyde under solventless conditions. The encapsulation process relies on the preferential reaction of polydimethylsiloxane immiscible epoxy resin and amine‐based hardener to form a cross‐linked spherical shell at the interface. The microcapsule dimensions and core content could be tailored by modulating the operating parameters, particularly stirring speed and Bz‐C: epoxy ratio. Spherical microcapsules with a core content of ～37% were obtained when the reaction was carried out at 600 rpm, while maintaining the reaction medium at 70°C with Bz‐C: epoxy ratio of 2.3 : 1. The simplicity and versatility of the present methodology are the forte of this technique, which widens the scope for large‐scale application of benzoxazines in the field of temperature triggered healing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42832.