Effects of nano-sized boron nitride (BN) reinforcement in expandable graphite based in-tumescent fire retardant coating

Abstract

Abstract. The purpose of in-tumescent fire retardant coating (IFRC) is to protect substrate from fire attack by limiting heat transfer. A range of coating formulations have been prepared using Bisphenol A epoxy resin BE-188 and polyamide solidifier H-2310 as two-part binder, ammonium polyphosphate (APP) as acid source, melamine (MEL) as the blowing agent, expandable graphite (EG) as carbon source and nano-boron nitride (BN) as inorganic nano filler. The filler was used to improve the performances of the APP-EG-MEL coating. The effects of nano-BN on the char morphology and thermal degradation were investigated by fire test, thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Xray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FESEM). The results showed that by substituting or reinforcing of 4% weight percentage of nano-BN, residual weight of the char increases by 23.82% compared to APP-EG-MEL coating without filler. Higher carbon content was obtained in the char and a more compact char was produced. The results indicated that nano-BN could be used as a filler to improve thermal stability of the APP-EG-MEL coating.

The influence of ceramic additives on intumescence and thermal activity of epoxy coatings for steel

“…They are frequently used on steel structures. [5][6][7][8][9][10][11][12][13][14][15][16] In order to receive effective intumescent coatings, the selection of appropriate components is necessary. An intumescent coating consists of active components (an acid source-a dehydrating agent, a carbon source-a substance that forms a char layer, a blowing agent), 17,18 directly participating in the swelling process, and passive components, indirectly supporting foam formation, facilitating paint production, dispergation and application (e.g., resin) 7,[17][18][19][20][21][22][23] or fillersfor example, nano-boron nitride (BN), vermiculite (EV), clay, wollastonite or glass flake ameliorating the thermal stability of coating.…”

“…An intumescent coating consists of active components (an acid source-a dehydrating agent, a carbon source-a substance that forms a char layer, a blowing agent), 17,18 directly participating in the swelling process, and passive components, indirectly supporting foam formation, facilitating paint production, dispergation and application (e.g., resin) 7,[17][18][19][20][21][22][23] or fillersfor example, nano-boron nitride (BN), vermiculite (EV), clay, wollastonite or glass flake ameliorating the thermal stability of coating. 6,10,13,16 Now the most popular acid sources are phosphorus compounds (e.g., ammonium polyphosphate-APP). Boric acid and its salts are less popular, but have the same mechanism of action.…”

“…Boric acid and its salts are less popular, but have the same mechanism of action. 1,4,6,9,12,14,19,21,24,25 Pentaerythritol constitutes the most common carbon source. Alternatively, dipentaerythritol, expandable graphite or cyclodextrins are used.…”

“…Alternatively, dipentaerythritol, expandable graphite or cyclodextrins are used. 1,4,6,12,14,15,24 Melamine, melamine phosphate, guanidine, urea are the example of blowing agents. 1,4,6,12,14 In any selection of the auxiliary substances, which are then used in fireproof coating systems, a special attention should be paid to the thermal and insulation properties of these substances.…”

“…During decomposition, they release compounds impeding oxygen access (e.g., water) or radicals disturbing burning process. They can also provide rigid coatings to protect deeper material layers or form intumescent coatings which deserve special attention 4–28 …”