Study On The Flame Retardant Performance Of Silica Synergistic Intumescent Flame Retardant Polystyrene

Polystyrene?Polystyrene,PS?,as one of the five commonly used polymers,is widely used in various fields due to its superior performance.However,polystyrene is extremely flammable and will drip severely during the combustion process,which has a great impact on the application of polystyrene.In order to improve the flame retardant properties of polystyrene,it is a common method to add intumescent flame retardants to polystyrene.Using synergists?such as nano-calcium,graphene,carbon nanotubes and mesoporous silica,etc.?to improve the flame retardant efficiency of intumescent flame retardants has become a research hotspot.Pentaerythritol?PER?and Ammonium Polyphosphate?APP?are used as intumescent flame retardants?IFR?.Nano-silica,micro-silica and hollow silica are used as synergists,respectively.PS/IFR/Si O₂ composite materials were prepared by blending method.The limit oxygen index and vertical combustion test were used to study the flame retardant properties of the composite material.The scanning electron microscope was used to characterize the carbon layer morphology of the composite material after combustion.The combustion behavior of the composite material was studied by a cone calorimeter.The thermal degradation process of the material obtained the performance and flame retardant mechanism of silica synergistic expansion flame retardant polystyrene.The research results show that the three kinds of silica?nano-silica,micro-silica,and hollow silica?have the same effect on the LOI of the composite.As the amount of silica added increases,the LOI tends to decrease.Among them,the increase in LOI was most obvious when the amount of hollow silica was 0.5wt.%?From 29.0 to 35.2?,and the LOI remained at 32.9 when the amount of hollow silica was 2 wt.%,Which was higher than PS/IFR3.9 units,and the LOI of the composite was lower than PS/IFR when the nano silica and micro silica were added at 2 wt.%.The combustion behavior of PS/IFR/Si O₂ composites shows that when the total amount of flame retardant is 30%and the amount of hollow silica added is 0.5 wt.%,The peak heat release rate?p HRR?of the composite is reduced by 27%,the total exothermic energy decreased by 14.5%,and the amount of residual carbon increased by 85.6%?from 13.2%to24.5%?.The research on the thermal degradation process of PS/IFR/Si O₂composites shows that the introduction of hollow silica reduces the thermal degradation temperature of PS/IFR/Si O₂ composites,and the amount of carbon residue in composites increases with the addition of hollow silica While increasing.The morphology of the carbon layer showed that the introduction of hollow silica significantly improved the compactness and continuity of the expanded carbon layer,which showed that the volume of the expanded carbon layer increased and the cracks decreased after the cone calorimetry test.The comprehensive effects of hollow silica on the combustion behavior and thermal degradation behavior of the composite materials show that the synergistic flame retardant mechanism of hollow silica on expanded flame retardant polystyrene is as follows:The addition of hollow silica promotes the formation of a dense carbon layer In addition,the barrier effect of the carbon layer on heat and gas is improved,so as to protect the internal matrix from burning and degradation.The performance of the carbon layer is increased by 70.4%,the heat release is reduced by 14.5%,and the specific area is reduced by 24.2%.