Study On The Flame Retardant Effect Of Metallic Phytate On Epoxy Resins

Epoxy resin(EP)is an important polymeric material which widely used in the engineering field.However,the high flammability of epoxy resin limits its application.In order to improve the flame retardancy of epoxy resin,the feasibility of metallic phytate as a flame retardant for epoxy resin was studied,and it was found that magnesium phytate(Mg-Phyt)is suitable to be a bio-based phosphorous flame retardant.To enhance the flame retardancy,Mg-Phyt and rice husk ash(RHS)were added together to achieve the phosphorus-silicon synergistic flame retardancy.In addition,the synergistic effect of different ratios of these two were investigated.The details were as follows:First,the metallic phytate(Mg-Phyt,Al-Phyt,Ca-Phyt,Sn-Phyt)were synthesized by the direct precipitation method.The influence of metallic phytate on the thermal stability and flame retardancy of epoxy resin was studied.The results show that the metallic phytate can slightly decrease the initial thermal decomposition temperature of epoxy resin,but slow down the decomposition rate.Compared with pure epoxy resin,the epoxy resin with 5wt%metallic phytate has better thermal stability,flame retardancy and smoke suppression.The flame retardancy is Mg-Phyt>Al-Phyt>Ca-Phyt>Sn-Phyt.The smoke suppression is Al-Phyt>Mg-Phyt>Ca-Phyt>Sn-Phyt.Considering the flame retardancy and smoke suppression of metallic phytate on epoxy resin,Mg-Phyt maybe an ideal additive.Then,to enhance the flame retardancy,the synergistic flame retardancy between Mg-Phyt and RHS was studied.The results show that Mg-phyt and RHS had synergistic effects on reducing the decomposition rate,heat release rate,total heat release,smoke production rate,total smoke release,toxic gas release and burning rate of epoxy resin.Mg-Phyt and RHS have a synergistic effect on char formation,which can form a silica-rich char layer containing Si-P and P-O-C structures with strong thermal stability to hinder the heat transfer into the epoxy resin substrate and reduce flammable gas emission.Therefore,the flame retardancy of epoxy resin can be further improved.Finally,the appropriate addition amount of Mg-Phyt as a flame retardant for epoxy resin was studied.The different ratios of Mg-Phyt and RHS were prepared,the flame retardancy and mechanical properties were investigated.The results show that when Mg-Phyt was added alone,10 wt%was the appropriate addition amount.When the total addition amount of Mg-Phyt and RHS was 10 wt%,the different ratios will affect the performance of epoxy resin.The ignition time,T5%,Tmax,char residues and LOI value increased with the increase of the proportion of RHS,and the damage to the mechanical properties decreased with the increase of the proportion of RHS.However,the mass ratio of the two was 1:1,the decomposition rate,heat release rate,total heat release,smoke production rate and burning rate of epoxy resin could be greatly reduced.