聚苯基甲氧基硅氧烷改性环氧树脂的阻燃性能研究

采用氧指数(LOI),UL-94,热失重(TGA)等手段考察了聚苯基甲氧基硅氧烷(PPMS)改性对环氧树脂(E-20)固化体系阻燃性能的影响.相比未改性环氧体系,当m(E-20)∶m(PPMS)=73∶时,改性环氧体系的LOI由纯E-20环氧树脂的17.5%上升到21.5%;水平火蔓延速率由36.23 mm/min降低到26.60 mm/min;质量损失为5%时的热分解温度由134.7℃上升到163.0℃,750℃时残炭量由0.21%增加到25.79%.此外,还通过红外光谱对燃烧后的残炭结构进行了分析,探讨了相关阻燃机理.

Study on the flame retardancy of polyphenylmethoxy Silicone modified epoxy resins

Silicone modified epoxy resins were prepared via the polycondensation of polyphenylmethoxy(PPMS) and epoxy resin(E-20).The flame retardant properties of the cured silicone modified epoxy resins were inverstigated by limiting the oxygen index(LOI),UL-94 testing and thermogravimetric analysis(TGA).When the mass ratio of E-20 to PPMS was 7∶3,the cured modified epoxy resin exhibits the optimal effect.The LOI value was 21.5%,higher than those of unmodified epoxy resin systems by 4%.The burning rate was reduced from 36.23 mm/min to 26.60 mm/min.The TGA date indicated that the thermal oxidative degradation process of the cured modified epoxy resin is composed of two steps.The 5% weight loss temperature of degradation was 134.7 ℃,higher than that of the unmodified epoxy resins by 28.3 ℃.The residue weight for the cured modified epoxy resin at the temperature of 750 ℃ was 25.79%,compared to the original date of 0.21% at 750 ℃.The chemical structure of char for the resin at the end of LOI test was analyzed by Fourier transform infrared.Based on the above results,the flame retardant mechanism was discussed.