Study On Flame Retardancy And Thermal Conductivity Of Styrene Butadiene Rubber Composites

Styrene butadiene rubber（SBR）is a common synthetic rubber with excellent wear resistance.It is often used in tires,conveyor belts and cables.However,due to its low thermal conductivity,it is easy to generate heat accumulation in the process of use,which accelerates the aging of rubber and has the risk of burning in serious cases,which reduces the safety of SBR and limits its application scope.Therefore,it is of great significance to study the rubber composites with flame retardancy and heat conduction.In this paper,three kinds of new boron nitride nanomaterials were designed and synthesized,and combined with aluminum diethylphosphite（ADP）,expandable graphite（EG）and ammonium polyphosphate（APP）,respectively,to study their effects on the flame retardancy and thermal conductivity of SBR.（1）A nanofiller（M-DOPO-BN）was obtained by surface modification of hexagonal boron nitride（h-BN）with vinyl teimethoxy silane（KH-171）and 9,10-dihydro-9-oxa-10-phosphaph-enanthrene-10-oxide（DOPO）,and compounded it with ADP to study the effects on SBR.The results showed that the addition of 20 parts per hundred of rubber（phr）ADP to the SBR composite has good flame retardant properties,but the amount of smoke generated increases.The flame retardant properties of SBR composites compounded with 3phr M-DOPO-BN and 17 phr ADP were not only further improved,but also the peak carbon monoxide production rate（p COP）and peak carbon dioxide production rate（p CO₂P）were reduced by 37.0%and 65.8%,respectively,compared with pure samples,showing a good smoke inhibition effect.In addition,the thermal conductivity is also improved to a certain extent.The real-time infrared and residue char analysis of SBR composites showed that the reasons for its flame retardancy and smoke suppression is that M-DOPO-BN can catalyze the formation of carbon,and the silica and boron nitride generated by decomposition during combustion can improve the density of residual char.（2）A hybrid flame retardant（PAPP-BN）was prepared by in situ synthesis of piperazine pyrophosphate on h-BN surface,and it was added to SBR together with EG to study their flame retardant properties and thermal conductivity.Adding 20 phr EG and 5 phr PAPP-BN to the SBR composite,the limit oxygen index（LOI）was increased from 19.5%to 28.5%,the peak heat release rate（p HRR）and total heat release（THR）were decreased by 69.9%and 39.4%,respectively,and the peak smoke production rate（p SPR）and total smoke production（TSP）were also decreased by 68.0%.and 48.1%.This is mainly due to the fact that the addition of PAPP-BN effectively increases the density of the EG residual char,making the fluffy residual char formed by EG denser,so that the release of heat and smoke is smooth and has been at a low level.In addition,the thermal conductivity of the SBR composite was increased by 78.8%.Better flame retardant properties and thermal conductivity expand the application range of SBR composites.（3）P-BN was prepared by surface modification of h-BN by polypyrrole doped with phytic acid,and it was added to SBR together with APP to study its effect on the properties of SBR.The test results showed that after adding P-BN as a flame retardant synergist,the p HRR and total THR of SBR composities reduce by 60.7%and 41.4%,respectively,compared with SBR1,and smoke production is also significantly reduced,indicating that APP and P-BN have good flame retardant and smoke suppression effects.This is mainly due to the good synergistic effect of APP and P-BN,which not only increases the density of residue char,but also increases the thermal stability of the residual char,which effectively block the release of smoke and heat.In addition,P-BN improves the compatibility between h-BN and the matrix,which improves the mechanical properties compared to the addition of unmodified h-BN composites,and the thermal conductivity of the SBR composite is also increased by 29.6%.Figures[56]Tables[22]References[102]...