Effect of expandable graphite and ammonium polyphosphate on the thermal degradation and weathering of intumescent fire‐retardant coating

Abstract

This research aims to study the effect of ammonium polyphosphate and expandable graphite on the intumescent coating formulations (ICF). The coating presented in this research article is based on carbon source expandable graphite (EG), blowing agent melamine, acid source ammonium polyphosphate (APP), epoxy resin as a binder with polyamide amine. The stability of the developed coating was verified at 950°C for 1‐hour fire test. The results showed that the coating is stable and well bond with the steel substrate. The char was characterized by using FESEM, XRD, FTIR, DTA, TGA, XPS, Py‐GCMS and Weathering Test. The morphology of the char was studied by SEM of the coating after furnace fire test. XRD and FTIR show the presence of graphite, borophosphate; boron oxide and sassolite in the residual char. TGA and DTG disclosed that EG improved the residual mass of coating. XPS analysis showed the char residue of IF5‐APP‐EG contains carbon and oxygen contents 47.50 and 40.70, respectively. Py‐GCMS analysis described that the IF5‐APP‐EG released less gaseous compounds. The weathering test illustrated that's the char expansion of coatings samples was decreased due to the presence of a humid environment and UV light. The IF5‐APP‐EG showed the maximum char expansion, lower substrate temperature and high residual weight among the studied formulations.

Effects of expandable graphite on char morphology and pyrolysis of epoxy based intumescent fire‐retardant coating

“…(a) IF3 showing smooth surface (b) holes and bubbles due to release of gases (c) IF3 showing the inner surface of char with holes due to dehydration and release of gases, (d) a spherical bubble which might be consists of carbon, oxygen, and phosphorus 45 [Color figure can be viewed at wileyonlinelibrary.com]…”

Preparation of melamine borate coated red phosphorus microcapsules and use of zinc borate as synergistic flame retardant in polyethylene

“…[9][10][11][12][13] Halogen-free flame retardants mainly include phosphorus, nitrogen, boron and metal hydroxide. [14][15][16][17][18][19][20] Red phosphorus (RP) is a common and practical inorganic flame retardant due to its high efficiency, and phosphorous content as well as low cost. [21,22] Furthermore, RP forms free radicals in burning to capture the active radicals and plays the role of flame retardant in the gas phase.…”

Bio-based arginine surface-modified ammonium polyphosphate: an efficient intumescent flame retardant for epoxy resin

“…14,15 In some cases, the blowing agents are also requested to further expand the char residuals. 16,17 Owing to the synergistic effects of the components, the APP-based IFR systems possess better ame retardance performance compared with pristine APP. To overcome the aforementioned drawbacks and improve the practical performance of pristine APP simultaneously, the microencapsulation technology is widely used to modify APP before it can function as an applicable ame retardant.…”