The Effect Of Intercalating Modified Hydrotalcite On The Fire Performance Of Intumescent Flame Retardant Coating

Steel structure intumescent flame retardant coating have drawn enormous attention in recent years due to its good flame retardancy.Intumescent flame retardant (IFR) formulations, which has attracted great attention because of its halogen-free and environmental friendly, is usually composed of three elements:an acid source, a blowing agent and a carbonic source. A suitable IFR formulation could provide good fire resistance and smoke suppression to coating during combustion.Layered double hydroxides (LDH) have gained much attention in recent years for they have shown good flame retardany and smoke suppression due to their unique chemical composition and layered structure. Two novel hydroxide was prepared and introduced to epoxy coating which containing an IFR system in order to improve the thermal stability, flame retardancy and smoke suppression properties. This paper contains three part:1?The effect of LDH on the flame retardancy, thermos stability and smoke suppression properties of the flame retardant coating was investigated by big panel method, smoke density box (NBS), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results revealed that LDH could improve the three properties of the flame retardant coating, when LDH is 9 phr, the equilibrium temperature of backside of iron plate is 186?, swelling height of the char is 3.8 mm, the rate of the residue char is 44.4%, and the smoke density rate is 36%.2?Sulfamic acid was intercalated into layered double hydroxide to prepare a novel sulfamic acid-intercalated MgAl-LDH (SA-LDH) through ion-exchange reaction. Fourier transform infrared (FT-IR) analysis confirmed the carbonate ions peak was disappeared and the presence of sulfamic acid in SA-LDH. X-ray diffraction (XRD) results revealed that the interlayer space of LDH had been enlarged from 0.76 to 0.92 nm. SA-LDH was prepared and introduced into epoxy coating containing an IFR system. The equilibrium temperature was 158? and the swelling height of the residue char was 10.2 mm at the presence of 9 phr SA-LDH. The residue char weight of SA-LDH/9phr flame retardant coating is 47.7% which is increased by 7.5% compared with that of LDH/9phr flame retardant coating. There was no obvious change between 9 phr SA-LDH (SDR=35.9%) and 9 phr LDH (SDR=36%) flame retardant coating in SDR analysis.3?Phosphaphenanthrene based carboxylic acid (DOPOMA) was synthesized byreacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) with maleic acid (MA). Then the DOPOMA was intercalated into layered double hydroxide (LDH) through ion-exchange reaction to prepare DOPOMA-LDH. Fourier transform infrared (FT-IR) analysis confirmed the carbonate ions peak was disappeared and the mainly characteristic bands of DOPOMA were observed in DOPOMA-LDH. X-ray diffraction (XRD) data shown that the interlayer space of DOPOMA-LDH had been enlarged from 0.76 to 2.11 nm. DOPOMA-LDH was prepared and introduced into intumescent coating. The smoke suppression, fire-resistant and thermal stability properties of epoxy flame retardant coating was investigated by SDR, Big panel method, SEM, and TG analysis. The SDR decreased to 27.5%, the equilibrium temperature decreased to 166? and the swelling height gained to 18.7mm at the presence of 6 phr DOPOMA-LDH. The results demonstrated that the thermal stability, fire-resistance properties and smoke suppression properties of epoxy intumescent flame retardant coating could be significantly improved by the presence of DOPOMA-LDH.