Epoxy/polymercaptan microcapsules composite: Synthesis, mechanics, and self-healing behavior

Abstract

To enhance the longevity of materials, minimize maintenance expenses, and optimize material performance. The wall material employed in this study was urea-melamine-formaldehyde (UMF), and a dual microcapsule self-healing system was established by synthesizing two distinct microcapsules of epoxy resin and polymercaptan via an in situ polymerization technique. Moreover, the reaction conditions were optimized. The reaction parameters were as follows: core-shell ratio of 2:1, surfactant concentration of 0.6 g/L (sodium dodecyl benzene sulfonate (SDBS): Arabic gelatin (GA) = 2:1), polymerization pH = 3.5, stirring rate of 700r/min. Then, the two microcapsules (The mass ratio of the two microcapsules is 1:1) were added to the epoxy resin matrix at 0, 2.5, 5, 7.5, 10, and 12.5 wt% to prepare the resin matrix with self-healing properties. The conical double cantilever beam (TDCB) was used to test the mechanical properties of the matrix. The results showed that the matrix with microcapsule content of 10 wt% had relatively better comprehensive properties, and the self-healing rate was 49.87% at room temperature. These findings provide valuable insights and potential for advancing the development of self-healing materials.