Encapsulation of trichloroacetic acid and trifluoroacetic acid for autonomous self healing coatings

Abstract

Microcapsules with TFA or TCA healing agents with an outer poly(melamine-urea-formaldehyde) (PMUF) were successfully synthesized for the first time, according to a review of published literature. The average sizes of the microcapsules obtained were measured to be 1.7 and 2 mu m for TFA/PMUF and TCA/PMUF, respectively. Both microcapsules were separately added to an epoxy-based coating formulation. To examine the self-healing properties, scanning electron microscopy images were examined at the moment that damage occurred and seven days later. A self-healing experiment showed that the more reactive PMUF/TFA microcapsules were more efficient than the PMUF/TCA microcapsules in repairing scratch damage in the coatings.