Exploration of Aloe Vera Gel Extract as a Bio-based Additive for Self-healing and Anti-corrosive Performance in Alkyd Resin Coatings

Abstract

The effectiveness of Aloe Vera (AV) gum extract as a corrosion-inhibiting and self-healing agent in alkyd-based coatings was investigated in the present study with the aim of developing environmentally friendly protective coatings. To identify the active chemical constituents responsible for corrosion inhibition, phytochemical screening of the AV gum extract was carried out and revealed the presence of bioactive compounds capable of enhancing coating performance. In this work, both urea-formaldehyde (UF) and melamine-formaldehyde (MF) resins were employed as wall materials for the encapsulation of the AV gum extract through microencapsulation techniques. The prepared microcapsules were characterized using Fourier Transform Infrared Spectroscopy (FTIR) to confirm successful encapsulation and the presence of functional groups associated with the extract and polymer matrices. In addition, the surface morphology and dispersion of the microcapsules within the alkyd coating matrix were examined using Scanning Electron Microscopy (SEM). Experimental design analysis and outdoor immersion tests demonstrated that the AV gum extract exhibited remarkable anticorrosion efficiency, improved barrier performance, and effective self-healing capability on damaged or scribed coating surfaces. The coatings containing AV-loaded UF microcapsules showed superior performance compared to MF-based systems. Overall, the study established that Aloe Vera gum extract can serve as an effective, sustainable, and low-cost additive for producing eco-friendly self-healing alkyd-based anticorrosive coatings without reliance on expensive synthetic co-reactants.