Synthesis And Properties Of Intumescent Transparent Fire Retardant Coating

A series of novel epoxy/PEPA phosphate(EPP)flame retardants were synthesized by1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane(PEPA),polyphos phoric acid(PPA),and epoxies of bisphenol A epoxy resin E51(EP)and 1,4-butanediol diglycidyl ether(BDE)with different proportions.The structure of EPP was characterized by ~1H nuclear magnetic resonance(~1H NMR)and Fourier transform infrared spectroscopy(FTIR).Then EPPs as flame retardants were blended with amino resin to prepare the transparent intumescent fire resistant coatings.The fire protection test showed that the best fire protection was obtained when the ratio of EP/BDE was 1/2.The results demonstrated that incorporation of EP could enhance the thermal stability and residual weight of fire resistant coating as well as the thermo-oxidation resistance of the char layers.The real-time FTIR proved that the decomposition process of fire resistant coatings included three stages bellow 550?.A cyclic phosphate ester acid(PEA)was synthesized by the reaction of phosphoric acid(PA),pentaerythritol(PER)and n-butyl alcohol(BA).Then nano-silica was successfully introduced into the structure of PEA to obtain SPEAs with different nano-silica contents.The influence of nano-silica on the thermal stability,flame retardancy and smoke suppression properties of coatings were investigated in details by cabinet method test,tunnel method test,cone calorimeter test,smoke density test,thermo-gravimetric analysis(TG),FTIR,SEM and EDS.The introduction of nano-silica could promote the formation of a more compact and intumescent char layer and then effectively reduces the heat and smoke release,thereby enhancing the flame retardancy and smoke suppression properties of coatings.