| The flame retardant was prepared by ammonium polyphosphate as the catalyst, pentaerythritol as the charring agent, and melamine as the foaming agent, then the important order of catalyst, charring agent and foaming agent on foaming expansion of flame retardant was studied through a group of orthogonal test. The results show that the factor order is: melamine, ammonium polyphosphate then pentaerythritol, and it shows the best fire resistant property when the proportion of ammonium polyphosphate, pentaerythritol and melamine is 1: 0.63: 0.68.The fire resistive coating for steel structure was prepared by flame retardant and titanium dioxide as the pigment and filler, water as the solvent, styrene acrylic emulsion, acrylic emulsion or polyvinyl acetate emulsion as the resin binder. The fire resistant test results show that the coating which used polyvinyl acetate emulsion as resin binder show the best property.The effect of the polyvinyl acetate emulsion, flame retardant and expandable graphite on the property of fire resistive coating was studied respectivly. The coating show the best property when the content of polyvinyl acetate emulsion is 32 %, flame retardant is 35 %, expandable graphite is 4 %, and titanium dioxide is 5 %.The coating was modified by added aluminum hydroxide or magnesium hydroxide. The TG DTA results show that aluminum hydroxide and magnesium hydroxide decomposed at 234 343 °C and 311 423 °C respectively, these reactions would absorb heat and form stable oxide.The XRF results show that the expandable graphite could improve the content of carbon in char layer. The SEM results show that the coating formed honeycomb carbon layer after the test of fire resistant. The TG DTA result shows that the thermal decomposition of fire resistive coating can be divided to four stages, the weightless rate is 4.43 %, 15.07 %, 37.8 % and 5.9 % respectively, and the most important factor of foaming expansion is the decomposition of flame retardant in the second and third stage. |
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