Epoxy resin composite coatings enhanced with CNTs-DA/ silica aerogel for superior heat insulation and flame retardancy

This study developed a novel carbon-based nanofiller CNTs-DA via a bridging method, which was then combined with thermally insulating filler silica aerogel (SA) and epoxy resin (EP) binder to fabricate a multifunctional coating with both thermal insulation and flame-retardant properties. The results show that with the addition of CNTs-DA, the flame-retardant efficiency of the coating first increases and then decreases. When the loading of CNTs-DA is 5 wt%, a uniform three-dimensional network structure of SA and CNTs-DA forms in the coating. Compared with the sample without CNTs-DA, the peak heat release rate (pHRR) and total heat release (THR) are reduced by 36.69% and 26.48%, respectively. The EP coating with the highest thermal insulation performance is the sample containing 5 wt% CNTs-DA at 200°C, which exhibits an insulation temperature of 64.8°C. In comparison, the EP coating with only SA shows an insulation temperature of 59.6°C. The synergistic interaction between SA and CNTs-DA results in the thermal insulation performance of the composite coatings. The CNTs-DA contribute to thermal insulation by effectively extending the pathway for heat conduction. This work demonstrates that uniformly dispersed SA and CNTs-DA can synergistically endow the EP coating with excellent thermal insulation and flame-retardant performance.