Microencapsulated Diepoxy-Functionalized Ionic Liquids to the Design of Self-Healable Epoxy Networks

An extrinsic self-healing mechanism based on microencapsulated healing agents represents an original way to produce self-healable thermosetting materials without modifying the structural architecture of the co-monomers. In this work, self-healing was achieved through poly(melamine–formaldehyde) (PMF) microcapsules containing a polymerizable diepoxidized ionic liquid monomer denoted as ILEM. First, a synthetic route to design ILEM@PMF microcapsules via in situ polymerization was developed and optimized through the choice of surfactants, core/shell ratios, and stirring speeds. Then, the obtained microcapsules (10 wt %) were incorporated into three different epoxy–amine networks and their effects on the morphology, thermal behavior, i.e., glass transition temperature ( T g ) and degradation temperature ( T d ), as well as on the mechanical properties were investigated. In addition, a pre-crack was generated with a fresh razor blade into the center groove of the epoxy networks and their self-healing performances were observed by scanning electron microscopy before and after the curing process.