Study Of Nanoparticles-phosphorus Hybrid Star Polymer/Polypropylene Composites:Preparation And Flame Retardant Property

This paper briefly discusses the combustion mechanism and flame retardant measures of polypropylene,and summarizes the research progress of element flame retardant mechanism,synergistic flame retardant polypropylene and bio-based flame retardants.The synthesis of double linked six arm star polymer?DLSASP?and preparation of its composites are studied.Meanwhile,the effect of phosphorus element and its compound system on the flame retardance,thermal stability and combustion properties of polypropylene composites is revealed.The essence of the effect of the flame retardant system on the thermal stability and flame retardance of polypropylene composites is revealed.A double linked six arm star polymer?DLSASP?is synthesized by phenyl dichlorophosphate?PDCP?,ethylene glycol?EG?,diphenyl chlorophosphate?DPCP?,hydroxyethyl methylacrylate?HCCP?,the structure and average molecular weight of DLSASP are characterized by FTIR and gel permeation chromatography.The flame retardant composites:DLSASP/PP,ATH-DLSASP/PP and Zn B-DLSASP/PP are prepared by polypropylene resin as matrix and aluminum hydroxide?ATH?and zinc borate?ZnB?.The flame retardancy,thermal stability,combustion properties and smoke release capacity of composites are characterized by limit oxygen index?LOI?,thermogravimetric analysis?TGA?,microscale combustion calorimetry?MCC?and smoke density tester,and synergistic flame retardancy mechanism is stduied by SEM and XPS.The decomposition activation energy?E_a?of composites are calculated by Flynn-Wall-Ozawa?FWO?method.The results show that with the increase of DLSASP addition,the temperature of mass loss5%,temperature of maximum decomposition rate,maximum mass loss rate,peak heat release rate and total heat release decrease,but LOI and residual weight show an increasing trend,this shows that DLSASP improves the thermal stability and flame retardancy of the composites,and decreases the combustion performance..When the amount of DLSASP is 30 wt%,the LOI value increases by 56.9%and the residual weight rate reaches 16.46%,phosphorus exists as polyvinylidene phosphate which promotes the formation of carbon in the matrix material,the flame retardancy of the material is improved..The thermal stability and LOI value of ATH-DLSASP/PP and ZnB-DLSASP/PP are higher than those of DLSASP/PP and increase with the increase of ATH and ZnB content.When the mass ratio of flame retardan is 1:1,the LOI value are 28.5%,28.9%,the residual carbon of the two systems contain aluminum phosphate?AlPO₄?and the coordination compound ZnO-P₂O₅,which proves that the complex system has synergistic effect.The carbon layer forme after combustion of the composite flame retardant system is compact and solid,and the carbon formation occurs on the surface of the oxide.The calculation results of activation energy show that the thermal stability of the composite system is better.The double linked six arm star polymer?DLSASP?which is prepared from phenyl dichlorophosphate?PDCP?,ethylene glycol?EG?,diphenyl chlorophosphate?DPCP?and hydroxyethyl methylacrylate?HCCP?has flame retardant effect on polypropylene.Besides,the synergistic flame retardant existed is proven by nano-particles and double linked six arm star polymer?DLSASP?.In this study,three kinds of polypropylene composites are prepared,the order of the flame retardancy is as follows:ZnB-DLSASP/PP>ATH-DLSASP/PP>DLSASP/PP.