Preparation of Isophorone Diisocyanate-loaded Microcapsules and Their Application to Self-healing Protective Coating

Abstract

The object of this study is to prepare microcapsules containing a diisocyanate compound, apply them to selfhealing protective coating, and evaluate the self-healing capability of the coating by atmospheric moisture. Isophorone diisocyanate (IPDI) polymerized under humid atmosphere, indicating that IPDI can be used as a healing agent. Microencapsulations of IPDI were conducted via interfacial polymerization of a polyurethane prepolymer with diol compounds. The formation of microcapsules was confirmed by Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The mean diameter, size distribution, morphology and shell wall thickness of microcapsules were investigated by optical microscopy and scanning electron microscopy (SEM). The properties of microcapsules were studied by varying agitation rates and diol structure. The self-healing coatings were prepared on test pieces of CRC board. When scratch was generated in the coatings, the core material flew out of the microcapsules and filled the scratch. The self-healing coatings were damaged and healed under atmosphere with 68~89% relative humidity for 48 h, and SEM and impermeability test for the specimens showed that the scratch could be healed by atmospheric moisture.Keywords: microencapsulation, isophorone diisocyanate, self-healing by atmospheric moisture.

Microcapsule-Type Self-Healing Protective Coating for Cementitious Composites with Secondary Crack Preventing Ability

“…Self-healing technology would provide improved public safety and reduced maintenance cost [ 1 , 2 , 3 , 4 , 5 ]. Although many studies of self-healing anticorrosive coatings for metal protection have appeared [ 6 , 7 , 8 , 9 ], reports on self-healing coatings for cementitious composites are very rare [ 10 , 11 ].…”