Enhancing the Char Strength of Expandable Graphite Based Intumescent Fire Retardant Coatings by using Multi wall Carbon Nano Tubes for Structural Steel

In the intumescent fire retardant (IFR) coating char thickness and its strength play a vital role to protect the base steel structure from the fire attack. The IFR coating contains expandable graphite (EG), ammonium polyphosphate (APP), melamine, boric acid, bisphenol A epoxy resin BE-188 (BPA) was used as a binder with ACR Hardener H-2310 polyamide amine and multi wall carbon nano tubes (MWCNTs). A range of different formulations were prepared to study the heat shielding effect and char expansion after fire test. The Intumescent coating was tested at 800oC for one hour in the furnace and it was found very stable and well bonded with the steel substrate. The characterization was done by using Thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and the char morphology was studied by field emission scanning electron microscopy (FESEM) after fire test. The results confirmed that MWCNTs enhanced the char resistant of IFR coating on steel substrate after fire test.