Influence of the Prepolymer Type and Synthesis Parameters on Self-Healing Anticorrosion Properties of Composite Coatings Containing Isophorone Diisocyanate-Loaded Polyurethane Microcapsules

Abstract

Self-healing anticorrosion composite coatings containing isophorone diisocyanate-loaded polyurethane microcapsules were developed, and comprehensive research on prepolymer and microcapsules synthesis, as well as functional composite coatings preparation and characterization, was performed. The influence of the prepolymer type and the concentration of the stabilizing agent used in the synthesis procedure on the properties of the microcapsules was studied in detail. For this purpose, three different prepolymers were prepared from toluene-2,4-diisocyanate (TDI) and either glycerol, 1,4-butanediol, or 1,6-hexanediol, and their chemical properties were investigated. Microcapsules were synthesized from the obtained prepolymers, according to the oil-in-water polymerization method, where 1,6-hexanediol was used as a chain extender, while the concentration of the stabilizing agent in the synthesis procedure was varied. Microcapsules prepared from TDI-glycerol prepolymer, synthesized in the presence of 10 wt% of the stabilizing agent, showed superior chemical, morphological, and thermo-gravimetrical properties; thus, they were incorporated into the coating in the concentration of 20 wt%. The prepared composite coatings demonstrated self-healing and anticorrosion properties, and thus the developed microcapsules show great potential for the incorporation into the composite anticorrosion coatings at critical points where damage can easily occur, providing longer and more efficient anticorrosion protection.

Investigation of Alumina-Doped Prunus domestica Gum Grafted Polyaniline Epoxy Resin for Corrosion Protection Coatings for Mild Steel and Stainless Steel

“…The damage is difficult to detect and repair, and thus provides opportunities for oxygen and water to penetrate through cracks and cause corrosion [ 3 ]. The development of self-healing coatings is key to repairing damaged surfaces spontaneously and thus protecting metal surfaces [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Currently, two types of self-healing coatings are used: First, coatings in which self-healing is achieved by reversible formation of hydrogen bonds with other functional groups.…”

Encapsulation of Cerium Nitrate within Poly(urea-formaldehyde) Microcapsules for the Development of Self-Healing Epoxy-Based Coating

“…Therefore, any defects caused by chemical and mechanical factors may provide direct access to corrosive agents to the metal surface. − However, one of the key challenges of the coating technology is how the organic coatings can be formulated for a high-performance anticorrosive system on metal structures. Self-healing systems have been introduced to address the aforementioned shortcomings, while the release of healing agents showed a long-term protective effect. − The incorporation of self-healing agents in organic coatings leads to a high-performance system with excellent protective properties against mechanical damages and corrosive agents. − In these systems, after creating environmental damage, they have the ability to recover their initial properties. − White et al achieved the first practical demonstration in the field of self-healing materials. Self-healing capabilities were demonstrated by embedding encapsulated dicyclopentadiene as a liquid healing agent into a polymer matrix containing dispersed catalysts.…”