| Vinyl ester resin(VE)has excellent properties and is now widely used in rail transportation,coatings,adhesives,electronic and composite materials.However,its flammability greatly limits the expansion of its application in the applications mentioned above.In recent years,phosphorus-based flame retardants represented by9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide(DOPO)and its derivatives have become a hot research spot for flame retardant epoxy resins by their environmental and efficient advantages.However,the application of DOPO and its derivatives in the flame retardant of vinyl ester resin is still rare.In this thesis,a new phosphorus-based flame retardant(PBDOO)with a bridging structure was designed,synthesized,and introduced into vinyl resins to enhance the flame-retardant properties of vinyl ester resins.The thermal stability,mechanical properties and combustion properties of the prepared flame retardant vinyl resin(VE/PBDOO)were investigated,and the flame retardant mechanism was discussed in depth.In addition,to further investigate the application of the flame retardant vinyl ester resin material in actual fire scenarios,the thermogravimetric analyzer and cone calorimeter data obtained from the experiments are used as material parameters in this article to simulate the combustion characteristics and development pattern of pure electric buses with vinyl ester resin as the seat material.The main research work of this thesis is as follows.(1)A new phosphorus-based flame retardant(PBDOO)was successfully synthesized by the addition reaction of DOPO and acetophenone,and its structure was characterized by infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR).Its thermal stability was analyzed by thermogravimetric analysis(TGA).The results showed that the initial decomposition temperature of the flame retardant in both air and nitrogen was above 350℃,much higher than the curing temperature of vinyl ester resin,and it can be used as a flame retardant in vinyl resin.(2)The thermal stability,combustion properties and flame retardant mechanism of VE/PBDOO composites were analyzed by thermogravimetric analysis,vertical combustion test(UL-94),limiting oxygen index test(LOI),cone calorimetry test,mechanical properties test,thermogravimetric infrared(TG-IR)and real-time infrared(RT-IR).The experimental results showed that when 15wt% PBDOO was added,the resulting VE/PBDOO composites could pass UL-94 V-0 with an oxygen index value of31.5%;the peak heat release rate and total heat release rate of VE/PBDOO materials with 15wt% flame retardant were reduced by 76.71% and 40.63%,respectively,compared with the VE samples.The experimental results of the thermogravimetric infrared and real-time infrared show that the flame retardant mechanism of PBDOO is mainly the quenching effect of phosphorus-containing radicals in the gas phase and the barrier effect of phosphorus-containing residual carbon in the condensed phase on combustible gases and heat.(3)The electric bus was simplified and a numerical simulation model was established to determine the parameters such as measurement point arrangement,fire source model,material combustion model,and grid settings.The simulation obtained the fire heat release rate,cabin temperature distribution,gas components,and smoke spread of the pure electric bus containing the seats in two different materials.A new phosphorus-based flame retardant(PBDOO)was prepared and used to prepare vinyl resin composites with good flame retardant properties,and the flame retardant mechanism of the PBDOO flame retardant was analyzed from the gas phase and condensed phase to broaden the application scope of the vinyl resin material.In addition,this paper also combines experimental data with fire simulation.Further,it verifies the combustion of this flame retardant material in practical applications by analyzing the fire simulation results of pure electric buses with flame retardant vinyl resin as seats.It provides a reference for further application of this flame retardant material.Figure [31] Table [15] Reference [112]... |
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