| With the development of science and technology,epoxy resin is widely used in various aspects because of its excellent performance.But it’s application is limited in some fields because of its poor flame retardancy.As people’s awareness of fire prevention increases,it is important to research on the flame retardancy of epoxy resin system.At the same time,the processibility,as one of the basic research contents of the resin system,is important for the later application of epoxy resin.In this research,the based resin system was composed of a self-made modified phenolic epoxy resin and curing agent.The based resin system was added with a modified flame retardant to get good processability,flame resistance and mechanical properties.The mixed flame retardant used in this experiment was modified by three kinds of flame retardants:Ammonium Polyphosphate APP,microcapsule coated Ammonium polyphosphate and Phosphazene flame retardant SPB-100.The resin system was tested by some characterization methods,including viscosity test,DSC,gel time test and oxygen index,to characterize the effect of each flame retardant and mixed flame retardant on the epoxy resin system.Through viscosity analysis,it was found that the addition of each flame retardant,Ammonium polyphosphate APP,microcapsule-coated ammonium polyphosphate and phosphazene flame retardant SPB-100 increased the viscosity of the epoxy resin system.The microcapsules coated Ammonium Polyphosphate had the greatest influence on the viscosity increase of the resin system.By the DSC test,it was found that the addition of Ammonium Polyphosphate APP had a slight effect on increasing the glass transition temperature of the resin system.The glass transition temperature of the epoxy resin system was significantly reduced,whenever added with microcapsule-coated ammonium polyphosphate and Phosphazene flame retardant SPB-100.The phosphazene flame retardant SPB-100 had the greatest effect on the glass transition temperature of the phenolic epoxy resin system.By the resin test of gel time and DSC,the results showed that the ammonium polyphosphate APP delayed the curing reaction of the epoxy resin system,while the other two flame retardants had nearly no significant retardation effect.According to the characteristics of the three kinds of flame retardants,such as viscosity-temperature of the epoxy resin system,the curing reaction effect and the influence of glass transition temperature,the three flame retardants were mixed as follows,Ammonium polyphosphate APP,Microcapsule-coated ammonium polyphosphate,phosphazene flame retardant SPB-100 according to the quality ratio of 20:5:5.Different amounts of mixed flame retardant were added to the epoxy resin system.Through the viscosity test,gel time test,and DSC analysis,the results indicated that as the amount of mixed flame retardants increases,the DSC curing curve gradually moves to the high temperature region,and the heat released during cured was reduced slightly.The glass transition temperature of the resin system increased slightly with the increase of the flame retardant.At the same time,it was found that with the increase of the flame retardant,the oxygen index of the epoxy resin system increased gradually,while the compressive strength and short beam shear strength decreased gradually.The study found that when the flame retardant content was to 24 parts,the viscosity of the modified epoxy resin system at 65℃ was about 43875 cps,which was satisfied to the technology of prepreg production.The oxygen index of the modified epoxy resin system was to 30.2%.Compared with the oxygen index of the pure epoxy resin,which was to 22%,the flame resistance was improved significantly.At the same time,the compressive strength and the short beam shear strength of the epoxy resin composites was 538Mpa and 50Mpa respectively,and the mechanical property met the basic-use requirements.The epoxy resin system modified with 24 parts of mixed flame retardants had good flame resistance,processabilities and mechanical properties. |
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