Preparation And Study Of Flame-retardant Silicone Rubber

Flame-retardant silicone rubber is an essential sealing material for nuclear power plant construction and belongs to a very critical building material.Its performance has a very important influence on the safety of nuclear power plants.In this paper,a new flame-retardant silicone rubber material was prepared according to the nuclear building material standards.Scanning electron microscopy was used to observe,analyze and characterize the microstructure of the flame-retardant silicone rubber after combustion.Through the hardness test,tensile test and analysis of the specimen fracture,the mechanical properties of the flame-retardant silicone rubber were comprehensively evaluated.The oxygen index and flame retardant rating of the flame-retardant silicone rubber were tested and analyzed.The thermal decomposition process of the flame-retardant silicone rubber was analyzed using a simultaneous thermal analyzer.The numerical simulation method was used to simulate the phenomenon of gas diffusion in the microscopic nano-sheets.In the first chapter,graphene oxide(GO)was prepared by the optimized Hummers method and modified with silane coupling agent KH550 to obtain modified graphene oxide(KH550-GO).The KH550-GO/MMT composite binary filler was added to methyl vinyl silicone rubber(MVQ)to obtain a KH550-GO/MMT/MVQ composite.The results show that KH550-GO and fully stripped MMT can form a composite nanosheet structure in the aqueous solution after sonication.Compared with pure MVQ,the tensile strength of the composite after adding KH550-GO/MMT with a mass ratio of 5%to 3:2 increased to 1.83 MPa,and the limiting oxygen index(LOI)increased from 30.8%to 38.5%.The rate increased by 7 percent and the carbon layer structure was denser.In the second chapter,the diffusion of gas from the KH550-GO and MMT nanosheets was simulated using finite element multiphysics software.This model demonstrated the effect of nanosheets on the gas barrier effect,and studied the nanosheets separately.The effect of layer arrangement direction,ratio of length to diameter,and dispersion mode on the gas barrier effect shows that the arrangement of nanosheets parallel to the concentration boundary,high aspect ratio,and dispersion mode have good barrier effects on gases.Finally,a one-dimensional model was used to optimize,which reduced the calculation of the entire model and improved the accuracy.In the third chapter,the effects of different compounding ratios of zinc borate(ZB)and melamine(MEL)on the flame-retardant properties of MVQ were studied.The mechanical properties and flame-retardant properties of ZB/MEL/MVQ composites were characterized and finally determined.With 20%ZB and 5%MEL,the composite material has an oxygen index of 33.6,a flame retardance rating of V-0,a tensile strength of 3.13 MPa,an elongation at break of 218%,a hardness of 78,and the composite material has the best resistance.Fire performance and mechanical effect.