Study On Preparation Of Phosphorus,Phosphorus-Nitrogen Compound Modified Acrylate Emulsion And Its Flame Retardant Properties

Acrylate emulsion has been widely used in the coating industry as one of the most important film-forming substances due to its excellent weather resistance,film-forming property,environmental protection and no pollution.However,polyacrylate is a flammable polymer,which brings huge safety hazards to people’s production and life.Therefore,people put forward higher requirements for the flame retardant property of acrylate emulsion.In this study,phosphorus-containing acrylate emulsion was synthesized by free radical polymerization with the monomers of PAM-100,MMA,BA and AA.Meanwhile,DNS-86,KPS and NaHCO3 were respectively used as emulsifier,initiator and pH buffer.In addition,in order to further improve the flame retardant property of latex film,phosphorus-nitrogen composite emulsion was synthesized by physical blending with waterborne polyimide(PI)emulsion and phosphorus-containing acrylate emulsion(20 wt%PAM-100).The main research contents of this thesis are as follows:1.The effects of DNS-86,KPS,NaHCO3 and AA content on monomer conversion,monomer aggregation rate,water absorption of latex films,emulsion stability,latex particle size and Zeta potential were systematically studied.The results showed that when the content of DNS-86,KPS,NaHCO3 and AA were 4 wt%,0.4 wt%,1 wt%and 2 wt%,respectively,the comprehensive properties of phosphorus-containing acrylate emulsion were best.FT-IR results showed that PAM-100 was successfully introduced into the polyacrylate chain.The flame retardant properties of the latex films were characterized by TGA,LOI,MCC and SEM.The initial decomposition temperature of the latex films were decreased,and the peak heat release rate and total heat release of the latex films were decreased significantly,but the carbon residue rate at 700℃ and the LOI values of the latex films were increased with the increase of content of PAM-100.When the content of PAM-100 was 20 wt%,the maximum LOI value of latex film was 23.5%,and the peak heat release rate and total heat release of the latex films were 215.4 W/g and 14.2 kJ/g,respectively.In addition,the number of pores on the surface of the carbon layer decreased,and a denser carbon layer was formed on the surface of the material with the increase of phosphorus content.It is proved that the introduction of PAM-100 can significantly improve the flame retardant property of pure acrylic latex film.2.Phosphorus-nitrogen composite emulsion was prepared by physical blending with phosphorus-containing acrylate emulsion(20 wt%PAM-100)and waterborne PI emulsion.When the content of deionized water was 70 g,the waterborne PI emulsion had the best stability.TGA and MCC results showed that the initial decomposition temperature of phosphorusnitrogen composite latex films were roughly equal.When phosphorus-nitrogen mass ratio of the latex film was 1:3,the sample had the minimum pHRR and THR,which were 67.67 W/g and 11.4 kJ/g,respectively.It is proved that this sample has the most excellent flame retardant performance,and the introduction of polyimide can further improve the flame retardant performance of the pure acrylic latex film.