Study On Mechanism And Preparation Of Waterproof Wood Flame Retardant Coatings

In this article,the phosphorus-containing flame retardants,melamine phosphate(MP)and pentaerythritol phosphate(PEPA),were used to prepare the waterproof wood flame retardant coatings,and the properties of waterproof wood flame retardant coatings were performed.The MP and PEPA,as flame retardants,ethylene vinyl acetate copolymer(VAE)emulsion and waterborne polyurethane(WPU)emulsion,as matrix,were used to prepare the waterproof flame retardant coating of MP/VAE,PEPA/VAE and PEPA/PU,respectively.To investigate the properties of these waterproof flame retardant coatings,the permeability tester,scanning electron microscope(SEM),energy disperse spectroscopy(EDS),thermogravimetric analysis(TG),the limiting oxygen index(LOI),Fourier infrared(FTIR),calorimeter test(CONE)and mechanical properties were carried out.1.The thermal stability of both VAE emulsion and WPU emulsion is excellent.The initial decomposition temperature of VAE emulsion and WPU emulsion is about320℃and 284℃,respectively.Both PEPA and MP also have good thermal stability,which can form metaphosphate during PEPA and MP heating.The metaphosphate can result in dehydration of polymer to form residual char.Moreover,when the thermal decomposition temperature reached 550℃,the residual char of PEPA and MP was49.51% and 21.8%,respectively.2.Through the waterproof properties of these three kinds of waterproof flame retardant coatings analysis,results showed that the three waterproof flame retardant coatings exhibited outstanding waterproof performance.3.With the addition of flame retardant to coatings increasing,flame retardant properties of waterproof flame retardant coatings increase gradually.The addition of40% flame retardant resulted in 5.9% increase in LOI of wood coating MP/VAE,4.9% and 14.9% increase in LOI of wood coating MP/VAE and MP/VAE,respectively.Moreover,with the addition of flame retardant to coatings increasing,the residual char of these waterproof flame retardant coatings gradually increased,and the totalsmoke release(TSR)and the total heat release(THR)gradually decreased,in addition,the carbon monoxide release rate of treated wood with waterproof flame retardant coatings was lower than that of untreated wood.4.Through the flame retardant performance of three kinds of waterproof flame retardant coatings analysis,results showed the flame retardant behavior of waterproof flame retardant coating of PEPA/PU is the best.