Optimization of Preparation Process for Chitosan-Coated Pomelo Peel Flavonoid Microcapsules and Its Effect on Waterborne Paint Film Properties

Abstract

In order to prepare chitosan-coated pomelo peel flavonoid microcapsules with antibacterial properties, chitosan was used as the wall material for the purpose of coating the core material, pomelo peel flavonoids. The pH of the microcapsule crosslinking reaction was 7.5, the mass ratio of the microcapsule core material to the wall material was 1:1, and the concentration of the emulsifier was 1%. The microcapsules obtained under these preparation conditions exhibited superior performance, morphology, and dispersion. Additionally, the yield and coating rates were recorded at 22% and 50%, respectively. To prepare the paint film, the microcapsules were added into the coatings at varying concentrations of 0%, 3.0%, 6.0%, 9.0%, 12.0%, and 15.0%. The antibacterial efficacy of the paint film for both bacteria was progressively enhanced with the incorporation of microcapsules. The antibacterial efficacy against Staphylococcus aureus was observed to be higher than that against Escherichia coli. As the content of microcapsules increased, the color difference in the paint film increased, the gloss loss rate increased, and the light transmission rate reduced. The tensile property and elongation at break reduced, and the roughness increased. At a microcapsule content of 6.0%, the paint film exhibited superior overall performance, with an antibacterial efficacy against Escherichia coli and Staphylococcus aureus of 46.3% and 56.7%, respectively. The color difference was 38.58. The gloss loss rate was 41.0%, the light transmission rate was 90.4%, and the paint film exhibited a large elastic region, with an elongation at break of 21.5% and a roughness of 1.46 μm.