Preparation of light-resistant and flame-retardant microcapsule and its application to enhance the flame retardancy of epoxy resin

Epoxy resin (EP) coating is widely used in the construction field due to its excellent performance. Microcapsules are prepared by self-assembly of TiO 2 on the surface of azodicarbonamide (ADC) to enhance the flame-retardancy and smoke suppression of epoxy resin, and to address the ultraviolet failure of azodicarbonamide in practical applications. By adding 5 wt% of azodicarbonamide microcapsules to the epoxy resin, the limiting oxygen index (LOI) of the composite EP was increased from 20 % to 31 % compared with the pure EP, reaching the level of flame-retardant material. Through cone calorimeter test (CCT), the total heat release (THR), peak heat release rate (pHRR) and total smoke production (TSP) of composite EP were reduced by 62.09 %, 54.88 % and 46.98 %, respectively, and the epoxy resin was equipped with a very good charring effect, which improved the flame retardancy. In addition, SEM images showed that the ADC was successfully coated by TiO 2 , which avoided the ADC from being exposed to UV leading to failure and enhanced its effectiveness in practical applications.