Synthesis Of Silicone Based Flame Retardants And Their Application In High Temperature Vulcanizing Silicone Rubber

The most commonly used flame retardants on the market usually contain halogen element,which can generate a lot of smoke and toxic gases when burned,causing great harm to human and ecological environment.It is inevitable to develop non-halogenated and environment friendly flame retardants to reduce the harm to human and environment.Currently,there are flame retardants which are effective and environmentally friendly such as phosphorus,nitrogen and silicon-based flame retardants.And they have different effects and applications due to the different flame retardant mechanism.Based on the design concept of green environmental protection,we synthesize two phosphorus and nitrogen-containing organic silicon flame retardants and boron-containing inorganic silicon flame retardant.And we apply the synthetic substances in the high temperature vulcanizing silicone rubber(HTV),and investigate the performance and flame retardant mechanism.The main research work are as follows:Firstly,aminopropyltriethoxysilane-cyclotriphosphazene(APTSCP)is synthesized with aminopropyltriethoxysilane(APTS)and hexachloro-cyclotriphosphazene(HCCP).The product is characterized with EA,FTIR and 1HNMR,respectively,and proved to be the target product.And the performance is investigated when APTSCP is added to high temperature vulcanizing silicone rubber(HTV).Results showed that the tensile strength and elongation of the composite material can be up to 7.9 MPa and 1614%,respectively when five portions of APTSCP are added.The limit oxygen index(LOI)is more than 27%,and the grade UL94 V-2 is achieved when twenty portions of APTSCP are added.The results of CONE test show that the heat release rate(HRR),smoke produce rate(SPR),total heat release(THR),mass loss rate(MLR)and fire growth index(FGI)related to pure HTV are all reduced.Therefore,APTSCP is good flame retardant and can improve flame retardant properties of HTV effectively.Secondly,1,1-spiro-(ethylenediamine)-3,3,5,5-tetra(aminopropyltriethoxysilane)-cyclotriphosphazene(SEAAPTSCP)is synthesized with aminopropyltriethoxysilane(APTS),ethylenediamine and hexachloro-cyclotriphosphazene(HCCP).The product is characterized with EA,FTIR and 1HNMR,respectively,and proved to be the target product.And the performance is investigated when SEAAPTSCP is added to HTV Results showed that the tensile strength of the composite material can be up to 8.1 MPa,when five portions of SEAAPTSCP are added.The LOI is more than 27%,and the grade UL94 V-2 is achieved when twenty portions of SEAAPTSCP are added.The results of CONE test show that their HRR,THR,MLR,SPR and FGI related to the pure HTV are all reduced.Therefore,SEAAPTSCP is good flame retardant and can improve flame retardant properties of HTV effectively.Finally,a new composite flame retardant consisting of zinc borate and silicon dioxide(ZB/SiO2)was synthesized via a facile gradual deposition route with raw materials of silicon dioxide(SiO2),zinc sulfate and borax.The product is characterized and analysised with SEM,FTIR and XRD,respectively,and proved to be the target.product.And the performance is investigated when ZB/SiO2 is added to HTV.Results showed that the tensile strength of the composite material can be up to 7.6 MPa,when twenty portions of ZB/SiO2 are added.The LOI is more than 27%,and the grade UL94 V-2 is achieved when fifteen portions of ZB/SiO2 are added.The results of CONE test show that their HRR,THR,MLR,SPR and FGI related to the pure HTV are all reduced.Therefore,ZB/SiO2 is good flame retardant and can improve flame retardant properties of HTV effectively.