Development Of A New Bio-based Phosphorus-nitrogen Synergistic Flame Retardant And Research On The Flame Retardant And Smoke Suppression Performance Of Polymer Materials

In modern society,a variety of polymer materials are increasingly used in construction,transportation,electronics,packaging,industrial machinery,aerospace and other fields.The use of organic polymers in such materials increases the risk of fire,as most of these materials are flammable.Therefore,it is not only of research value,but also of practical value to formulate effective flame retardant schemes for different kinds of polymers.Based on this point of view,three flame retardant systems were designed and applied to expandable polystyrene(EPS),cotton fabric,natural rubber(NR)and ethylene propylene diene monomer(EPDM),respectively.The first part designed a phytic acid(PA)/urea(U)flame retardant coating PACU:PA can undergo a complex reaction with U in the liquid phase to form a new phosphorus-nitrogen synergistic flame retardant coating PACU.It is applied to the surface of EPS foam(300?m)to achieve flame retardancy.The results show that PACU has obvious flame retardant and smoke suppression effect on EPS.In the vertical combustion(UL-94)test,the EPS foam board coated with PACU coating can finally reach V-0 level,and the limiting oxygen index(LOI)is increased to 31.5%;in the cone calorimetry(CCT)test,Compared with pure EPS,the ignition time(TTI)was extended from 3s to 14 s,the peak heat release rate(PHRR)was reduced by 35.1%,and the total smoke release(TSP)was reduced by 58.1%,showing excellent after-burning smoke suppression performance..In the second part,sodium phytate(PA-Na)and U were used to synthesize new flame retardant U@PA-Na.In this part,LBL technology was used to assemble PA-Na solution with negative charge and U solution with positive charge on the surface of cotton fabric by electrostatic force to achieve flame retardant.The results show that compared with pure cotton fabric,the flame-retardant cotton fabric can pass the UL-94 test and reach B1 level.LOI has reached 34.6%,which has doubled;According to CCT data,compared with pure cotton fabric,the PHRR and total heat release(THR)of the flame-retardant composite decreased by 45.6% and 15.2% respectively,the Mass loss rate decreased by 15.9%,and the TTI was greatly prolonged,from 14 s to 44 s,with an increase of 214.2%.In the third part,PA,Melamine(MEL),Modified Sepiolite(OSEP)and Prolifera(EP)Cellulose were used to synthesize a new phosphorus nitrogen synergistic expansion flame retardant and smoke suppressor(PMO): In this part of the experiment,PA reacted with MEL in the liquid phase to produce intermediate PM,and sepiolite(SEP)was surface modified under the action of silane coupling agent(KH550),so that PM can be loaded on the surface of OSEP,and PMO can be synthesized after compounding with EP.PMO system was added into natural rubber(NR)and ethylenepropylene-diene monomer(EPDM)by ontology,and its flame retardant and smoke suppression effects on rubber materials were investigated.The experimental results show that in the UL-94 test,compared with pure NR and EPDM,the NR after adding50 phr PMO reached V-1 level,the LOI was increased to 29.7%,the TTI was prolonged from 6s to 22 s,and the PHRR decreased by 42.8%.THR decreased by 44.5%,TSP also decreased by nearly 40%;EPDM after adding 50 phr PMO reached V-0 level,LOI increased to 31.1%,TTI extended from 6s to 29 s,PHRR decreased by 55.8%,THR decreased 69.4%,TSP and especially TSP dropped by more than 73%.