Preparation and characterization of ethylenediamine-polyurea microcapsule epoxy self-healing coating

Abstract

Polyurea microcapsules with Ethylenediamine (EDA) as the core material were synthesized.A set of characterization methods, including optical and scanning electron microscopy (OM andSEM), the Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA)were used to confirm the microcapsule morphology and chemical structures. The influence ofemulsifier content and stirring rate on size and morphology of the microcapsules was investigated,and the self-healing performance of EDA-Polyurea microcapsule/epoxy coatings was evaluatedby electrochemical impedance spectroscopy (EIS) measurements. The results showed that themicrocapsules obtained had good spherical shape with a mean diameter of 0.54-0.70 μm. Comparedwith pure core material, the microcapsule showed excellent thermostability, and the content of corematerials was up to 56.00 wt%. The epoxy coating with 5.0 wt% EDA-Polyurea microcapsulesachieved average corrosion resistance efficiencies of 90.00%, significantly enhancing the capability ofthe scratched coating to resist external corrosion.