Nanoclay-modified microcapsules as a latent curing agent in epoxy

Abstract

Application of microcapsules as a latent curing agent has been attracted a lot of attention, recently. However, in this type of latent curing agent, the leakage of core material from the microcapsule shell is a major problem. In this study, nanoclay particles were used as a promising approach to prevent the flow out of core materials from the microcapsules’ shell. To this end, nanoclay particles were dispersed in a solution of solid epoxy resin in acetone under sonication process and then were used for microencapsulation of 1-methylimidazole (1-MI) via solvent evaporation method. Scanning electron microscopy was used to study the shape and morphology of the prepared microcapsules. 1-MI content of microcapsules was measured using thermal gravimetry analysis. Curing behavior of microcapsule-embedded epoxy resin was investigated using differential scanning calorimetry and rheometry measurement. In comparison with the neat microcapsules, nanocomposite microcapsules showed better barrier property and longer gel time at high temperature, which can be attributed to the presence of platelet nanoclay particles throughout the microcapsules’ shell.