ENHANCEMENT THE PERFORMANCE OF THE INTUMESCENT COATING BY INCORPORATING TALC AS FLAME RETARDANT FILLER

Fire protection has become an important issue in construction industry. In fact, prevention for structural collapse is vital as to ensure the safety of the people from the building. Intumescent coatings are designed to prevent the heat, flames or fire from spreading. Talc has been used as a fire retardant filler in this study to enhance the performance of intumescent coating in order to protect the underlying substrate. The main reason of choosing talc as a filler is because it can withstand temperature above 1300°C due to the high silicate content. The aim of this work is to study the effects of incorporating talc in the formulation towards the physical, chemical and mechanical properties of intumescent coating. Five formulations were burned in a furnace at 800°C and the physical properties in terms of expansion and adhesion to steel substrate were observed. In order to study the effects of water permeability towards coating, chemical properties measurement of the coating was determined by performing the water immersion test according to ASTM D870-97 test method. The coating was immersed in a distilled water for 358 hours and the weight changes were then measured. Morphology of char before and after water immersion was analysed using Scanning Electron Microscopy (SEM). Lap shear test was performed according to ASTM 3163 test method to test its mechanical properties. The maximum shear strength was found to be 7.65 MPa for F5 formulation and 0.42 MPa for formulation without talc respectively. X-Ray Fluoresence (XRF) and X-Ray Diffraction (XRD) were used to analysed the chemical composition of char. Thermal stability of the coating was conducted using thermogravimetric analysis (TGA) while Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize the functional group in a char sample.
Heat insulation test was performed according to ASTM E119 standard test. The test was conducted for 100 minutes and the backside temperature of the steel was measured.
Result shows that heat insulation characteristic of the intumescent coating was improved due to the high content of talc which provides good heat insulation to the substrate as the char expand and exhibiting good cellular structure to protect the steel from fire exposure. After reaching an equilibrium, the temperature of the coating were 124°C for F1, 125°C for F2, 123°C for F3, 113°C for F4 and 69.6°C for F5, respectively.