Study On Flame Retardancy Of Silicone Rubber Foam Containing MCA Microcapsules

Because the silicone rubber foam molecular chain contains a large amount of C and H elements,it can continue to burn itself.To this end,we used microencapsulation technique to improve the problems of poor compatibility and greater hygroscopicity of ordinary flame retardants and silicone rubber foam.The morphological characteristics,composition,pyrolysis process and thermal stability of microcapsules made from different wall materials were compared.The flame retardant process and flame retardant mechanism of foam containing microcapsules were analyzed.In this way,a silicone rubber foam material with better comprehensive performance and flame retardant performance was obtained.This thesis mainly carried out three aspects of research,specifically:the research obtained the best ratio of particle uniformity and wrapping property of microcapsules of different wall materials;comparative analysis of the composition,thermal stability and pyrolysis process of microcapsules of different wall materials;the test found the difference in mechanical properties and combustion characteristics of different wall material microcapsules added to silicone rubber foam.First,polyethylene glycol(PEG)and silicon dioxide(SiO2)were selected as the wall materials,and melamine cyanurate(MCA)flame retardant microcapsules were prepared by emulsion polymerization and sol-gel methods,respectively.The results show that when the molecular weight of PEG is 20000,the microcapsules prepared with OP-10 as emulsifier have uniform particle size and the weight percentage of N element on the surface is 24.33 wt%;using silica(SiO2)as the wall material,the optimal ratio of emulsifier Tween 80:CTAB is 4:6;the reaction temperature is 65?,the hydrolysis condensation reaction is more stable when the solution was acidic,and the microcapsules were more complete.Secondly,a comparative analysis of the flame-retardant microcapsules prepared by the two wall materials show that the SiO2/MCA microcapsules prepared by the sol-gel method have better performance in terms of composition,pyrolysis temperature,and thermal stability.Finally,two types of microcapsules were added to silicone rubber foam,and the effects of the two types of microcapsules on the mechanical and flame retardant properties of silicone rubber foam were compared.The results show that:comprehensive analysis of mechanical properties and flame retardancy,the performance of SiO2/MCA microcapsule silicone rubber foam containing 5 wt%is the best,the peak heat release rate is reduced to 85.71 kW/m2,and the fire hazard is significantly reduced.Combining the analysis of residual carbon on the surface of the material and gas evolution during pyrolysis,it was found that the flame retardant mechanism of MCA flame retardant microcapsule silicone rubber foam is mainly gas phase flame retardant,supplemented by condensed phase flame retardant.Therefore,flame retardant microcapsules can improve the stability and flame retardant properties of silicone rubber foam.