Research Of Fire Performance And Smoke Suppression Of Intumescent Flame Retardant Coating

With the increasing trend of more stringent fire safety regulations, demands for reduction of the fire hazard posed by highly combustible materials such as wood, plastics, textiles, etc., have gained importance in recent years. A suitable flame retardant (FR) treatment might be able to retard the ignition of these materials and/or decrease flame spread, thereby obviating fire hazards and loss of life and destruction of property. The use of flame retardant coatings has become one of the most convenient, economical and most efficient way to protect the substrates against fire. Some of its advantages are given as follows:FR coatings allow the concentration of fireproof properties at the surface of the substrate along with preserving the bulk properties of the material (e.g. mechanical properties), and can generally be combined with an attractive aesthetic feature.IFR systems have attracted great attention because of halogen-free and environmental friendly, are usually composed of three elements, an acid source, a blowing agent and a carbonic source. Compared with halogen-containing flame retardant, it also has some drawbacks, such as low-thermal stability and low-fire performance. The intumescent char produced from the synergistic interaction among these elements protected the wood or steel from heat and oxygen. Some fireproof fillers have proved that they can significantly improve the flame properties.In this paper, flame-retardant coatings have been prepared by adding anatase-TiO2/rutile-TiO2to ammonium polyphosphate-pentaerythritol-melamine (APP-PER-MEL) coating. The effect of TiO2on the improvement in fire-resistant properties of the APP-PER-MEL coating is investigated using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Thermogravimetry (TG) and Big panel method. When rutile-TiO2is30phr, the fire resistant time of coating can reach up to73min, is much longer than that of the sample containing30phr anatase-type TiO2(34min.) The TG data shows that TiO2is helpful to the char formation of the APP-PER-MEL system at300-440℃. The SEM date shows that "honeycomb" char structure can form to block heat transferring to the substrate and protect the substrate from fire. XRD date shows it can be concluded that anatase-type TiO2has converted into rutile-type TiO2at high temperature (above912℃). The results of XRD analysis and FTIR spectra show that during the thermal decomposition of the intumescent coating, TiO2is separated from the matrix and transfers to the surface of the coating immediately, meanwhile the char is generated due to complicated reaction also transfer to the outer surface. Smoke density meter date shows that when anatase-TiO2is60phr, SDR can reach up to19.4, effective to smoke suppression of intumescent flame retardant coating, the reason is maybe that the specific surface area of anatase-TiO2is larger than rutile-TiO2.Secondly, flame-retardant coatings have been prepared by adding MoO3/APM to ammonium polyphosphate-pentaerythritol-melamine (APP-PER-MEL) coating. The fire resistant time of coating can reach up to60min When MoO3is2phr, is much longer than that of the sample containing2phr APM (65min.). The TG data shows that MoO3/APM is helpful to the char formation of the APP-PER-MEL system, can enhance the thermal ability, the residual mass of coating containing2phr MoO3and APM respectively is up to35%and25%, superior to the blank coating. The SEM date shows that "bubble and honeycomb" char structure can form to block heat transferring to the substrate and protects the substrate from fire. FTIR spectra shows that the inner char is abundant compared with the outer char because of the protection of the outer char layer when heated. Smoke density meter date shows that the smoke density of mixture of APM and MoO3(SDR-8.7) is littler compared with the single one of APM (SDR=21.3) and MoO3(SDR=22.2), all superior to the blank coating (SDR=29.3), conclude that they are effective to smoke suppression of intumescent flame retardant coating.Lastly, flame-retardant coatings have been prepared by adding ZB/ZnO to ammonium polyphosphate-pentaerythritol-melamine-titanium dioxide (APP-PER-MEL-TiO2) coating. The fire resistant time of coating can reach up to126min When ZB is18.75phr, is much longer than that of the sample containing18.75phr ZnO(110min). The TG and CONE data shows that ZB/ZnO can enhance the thermal ability, the residual mass of coating containing ZnO is up to50%. The SEM date shows that bubble char structure can form to block heat transferring to the substrate and protects the substrate from fire. The CONE date shows that the peak of smoke produce rate(SPR) of coating containing ZB is only0.013m2/s, littler than the blanking coating(0.018m2/s) and the coating containing ZnO(0.021m2/s). Smoke density meter date also shows that the effect of ZB is superior to ZnO on smoke suppression of intumescent flame retardant coating.