Study On Preparation And Properties Of Intumescent Flame Flame Retardant Flame Retardant Silicone Rubber

In recent years,with the rapid development of China's national economy,the application fields of rubber products are becoming wider and wider,and the demand is increasing.Among them,silicone rubber is widely concerned in the field of flame retardant due to its excellent weather resistance,heat resistance,aging resistance and radiation resistance.It is of great significance to research and prepare a high-performance intumescent flame-retardant silicone rubber composite material which uses silicone rubber as the matrix and can effectively block the heat conduction to the inside and reduce the temperature of the outer surface of the covered building,equipment and other objects.This subject is based on two-component condensation type room temperature vulcanized liquid silicone rubber?RTV-2 glue?,using melamine polyphosphate?MPP?/pentaerythritol?PER?compound type expansion flame retardant,aluminum hydroxide?Al?OH?₃?,modified hollow glass microspheres?HGM?,zinc borate?ZB?,etc.as fillers,mechanically blended into the silicone rubber?SR?matrix,The effects of the content of intumescent flame retardant system?IFR?,hollow glass microspheres?HGM?and zinc borate?ZB?on the flame retardancy,mechanics,thermal stability,thermal conductivity and density of silicone rubber composites were researched and analyzed.A low density intumescent flame retardant material with high temperature resistance,low thermal conductivity and high thermal stability was obtained.Firstly,the effect of the addition amount of intumescent flame retardant?IFR?on the properties of MPP/PER type intumescent flame retardant silicone rubber composites was researched.The results show that when the ratio of MPP to PER is 3:1,the tensile strength of composites tends to decrease with the increase of IFR,and the elongation at break also decreases.When the amount of IFR added exceeds 30%by weight,the tensile strength of the silicone rubber composite material decreases to a greater extent.The initial decomposition temperature T5%of the composite increases gradually,and the residual weight gradually increases and then decreases slightly.When the addition amount of IFR is 30wt%,the residual rate of the composite reaches a maximum of 33.1%.the oxygen index?LOI?value of the silicone rubber composite gradually increased.Considering the influence of the amount of IFR added on the properties of the composite,the optimal addition amount of IFR is determined to be30wt%.Then,HGM was used as a filler and filled into MPP/PER type intumescent flame retardant silicone rubber and the effect of HGM content on the properties of silicone rubber composites was researched.It is found that the tensile strength of silicone rubber composites increases first and then decreases with the increase of HGM content,and the elongation at break decreases with the increase of HGM content.When the HGM content is 30wt%,the silicone rubber composites The tensile strength reaches a maximum of 4.23 MPa.With the increase of HGM content,the T5%and residual weight of the silicone rubber composites increase gradually.With the increase of HGM content,the LOI value of the composite increases gradually and the temperature of the back surface is gradually decreasing.With the increase of HGM content,the thermal conductivity of the composite decreases gradually.When the HGM content is 30wt%,the thermal conductivity value reaches the lowest value of 0.23W/?m.K?,and It was concluded that the optimum amount of HGM added was 30%by weight.Finally,ZB was added to MPP/PER intumescent flame retardant silicone rubber to research the effect of different content of ZB on the properties of silicone rubber composites.The results show that with the increase of ZB content,the mechanical properties of silicone rubber composites decrease gradually,and the elongation at break decreases gradually.With the increase of ZB content,the T5%and Tmax of composites gradually increase,and finally tend to be stable.The residual rate increases gradually.With the increase of ZB content,the LOI value of the composite increases gradually.With the increase of ZB content,the expansion ratio of the composite decreases gradually,and the strength of the formed carbon layer increases gradually.When the ZB content exceeds 15%by weight,the thermal expansion ratio of the composite material decreased greatly,indicating that the ZB addition amount was controlled within 15wt%,and the ZB addition amount had little effect on the expansion property of the composite material.It can be seen that when the amount of ZB added is 15%by weight,the overall performance of the silicone rubber composite is optimal.