Synthesis and characterization of an intumescent halloysite based fire-retardant epoxy system

Abstract

In this research, a halloysite-based nitrogen-phosphorous fire retardant epoxy system was evaluated. The synthesized melamine phosphate in combination with pentaerythritol as an intumescent fire retardant which was effective in previous studies was introduced. To achieve a strong and thermally stable char residue a tubular high aspect ratio halloysite nanotube to make bridgeable network and reducing flame spread as a promising reinforcing nanoclay was proposed. The present study focuses on investigating the fire retardant capabilities of partially cured melamine formaldehyde resin that has been used to cover fire retardant additives. The synthesized fire retardant additives were characterized by spectroscopic, microscopic analysis, etc. The synthesized fire retardant additives had an excellent effect on fire retardancy of epoxy resin and the strength of residual char. Thermogravimetric analysis data showed that suitable amount of halloysite had positive effect on the char residue to protect the substrate at high temperatures. Cone calorimetery test showed that the epoxy based fire retardant sample was successful to release heat slowly, and slow down the burning process by the formation of an efficient char on the surface of the substrate. The total smoke released by epoxy based fire retardant sample was 1469.1 m2/m2 while that of neat epoxy was 5589.6 m2/m2.