Preparation and performance analysis of organic polyborosilazane-modified epoxy resin-based intumescent flame-retardant thermal insulation coatings

Abstract

To improve the thermal insulation and flame retardancy properties of epoxy resin-based intumescent coatings, this study served epoxy resin (EP) as the base material, melamine (MEL), pentaerythritol (PER), and ammonium polyphosphate (APP) as the blowing agents, char-forming agents, and dehydration catalysts, palgorskite and sepiolite as fillers, and PSNB as the modifying agent to prepare the high-performance modified coatings by using the straightforward blending modification technique. With the introduction of PSNB, the coating achieves an in-situ vitrification/ceramisation effect in the char structure when exposed to fire, thus fully enhancing its fire protection capability Compared to the blank sample (EPC), the modified coating (EPC-PSNB-3) exhibited optimal performance when the PSNB content reached 30 wt%. In a 2 h thermal insulation performance test, the substrate backside temperature of EPC-PSNB-3 was only 165.99 °C. The Limiting Oxygen Index (LOI) value increased by 33.20 %. In cone calorimetry tests, EPC-PSNB-3 showed reductions of 63.56 %, 64.98 %, 21.37 %, and 24.35 % in peak heat release rate (PHRR), peak smoke production rate (PSPR), total heat release rate (THR), and total smoke production (TSP), respectively, compared to EPC. The residual char mass increased by 45.19 % with PSNB incorporation. The introduction of PSNB not only promotes the increase of residual char but also densifies its internal porous structure, enhancing its thermal barrier capability.