Electrosprayed PMMA microcapsules containing green soybean oil-based acrylated epoxy and a thiol: a novel resin for smart self-healing coatings

Abstract

For the first time, the binary components of a self-healing epoxy system was developed comprising of a green acrylated epoxy resin and its thiol-based curing agent encapsulated in a poly (methyl methacrylate) (PMMA) shell by electrospraying technique. The field emission scanning electron microscopy images revealed that the two microcapsules formed were almost spherical with rough and irregular surfaces. The average diameter of microcapsules ranged from 1.165 to 1.418 µm for the two microcapsules. FTIR spectra and thermal analysis were used to investigate the encapsulation of acrylated epoxy resin and thiol curing agent in PMMA as well as the kinetics of crosslinking reaction between the two components. Based on FTIR spectra, the thiol curing agent was involved in the crosslinking reaction with the epoxy group (810 cm −1 ) and the C = C segment (1634 and 1613 cm −1 ) of acrylated epoxy resin. The DSC results indicated an exothermic peak (at 65 • C) proving that this system is efficient in self-healing epoxy resins for coating applications. Furthermore, the ability of epoxy coatings to protect the scratched coating substrate from corrosion media (the healing performance) without microcapsule, with dual microcapsules, single healing agent-containing microcapsule and single curing agent-containing microcapsule were also evaluated using potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS). The results were in line with the potentiodynamic polarization and the EIS. The highest self-healing efficiency (78%) was obtained for binary capsule concentration of 1%, indicating presence of sufficient amount of material to heal the cracks.

Self‐healing polymers for aviation applications and their impact on circular economy

“…These are used for all places where transparency is required. Shahla Ataei et al 82 reported extrinsic self‐healing in PMMA shell by dual microencapsulation using a phase separation technique using epoxidized soyabean oil (AESO) as healing agent and trimethyolpropane tris(3‐mercaptopropionate) (TMPMP) as curing agent. The healing mechanism was reported due to crosslinking reaction between the reactive epoxy and acrylate functional group in AESO and thiol functional group in TMPMP.…”

Repeatable Self-Healing of a Protective Coating Based on Vegetable-Oil-Loaded Microcapsules

“…Drying (or semi-drying) oils have been used in industrial applications, such as coatings and paints. In particular, several studies have been reported on the application of drying oils (for example, linseed oil, soybean oil, or tung oil) to microcapsule-type self-healing protective coatings [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ].…”

Cobalt (II) used as a catalyst to drying properties of healing agents for self-healing coatings / Cobalto (II) utilizado como catalisador de propriedades de secagem de agentes de cura para revestimentos auto-regenerativos

“…Once the crack occurs, the oil flows into the damaged area where, through reactions between its unsaturated bonds with the atmospheric oxygen, called the oxidative polymerization process [2][3][4][5] , it is capable of forming a solid film, preventing the exposure of the metal to corrosion agents. Linseed oil (LO) is currently reported in many works as one of the most used drying vegetable oils for self-healing purposes [2,5] , although other studies related to the use of soybean [6,7] and sunflower [8] oils are also found. Chia seed oil (CO) is known as Brazilian Journal of Development, Curitiba, v.8, n.2, p. 9723-9740 feb. 2022. the vegetable oil with the highest content of poly(unsaturated) bonds in its fatty acids chains [9] and its applications are no longer restricted to the food industry, due to its increasing crops even in non-Latin American countries [10] .…”