膨胀阻燃剂与蒙脱土复合阻燃体系对环氧树脂阻燃抑烟性能的影响

Influence of intumescent flame retardant/montmorillonite on the property of epoxy resin

以聚苯氧基磷酸联苯二酚酯(PBPP)与聚磷酸铵(APP)组成膨胀阻燃体系(IFR),同时为提高抑烟性能将一定量蒙脱土(MMT)引入阻燃体系中。将此体系应用到环氧树脂(EP)的阻燃改性中,以间苯二胺(m-PDA)为固化剂制得阻燃改性EP材料。通过极限氧指数(LOI)、垂直燃烧(UL-94)、热重(TG/DTG)、锥形量热(CONE)和扫描电镜(SEM)分别探究了材料的阻燃性能、热降解行为、燃烧行为以及微观形貌。结果表明:5%IFR+1%MMT(wt,质量分数,下同)的阻燃剂可使EP达到UL 94V-0级;10%IFR+1%MMT可将极限氧指数提高到29.2%;同时,改性EP的燃烧性能得到很大提高,平均热释放速率(AvHRR)下降了52.0%,热释放速率峰值(PkHRR)下降了33.2%,总烟产生量(TSP)下降了70.0%;炭层形态研究显示,改性后的EP燃烧后能形成致密、封闭的炭层,能有效阻碍热量释放与烟雾扩散。

The epoxy resin was modified with intumescent flame retardant(IFR)--polyphenoxyphosphoric biphenyl ester(PBPP)blended with ammonium polyphosphate(APP)was incorporated into epoxy resin and cured by m-phenylenediamine(m-PDA)to form a flame retardant thermoset FR-EP.The mass fraction of 1%montmorillonite(MMT)was added to IFR in order to improve smoke suppression performance.The effect of intumescent flame retardant(IFR)coupled with montmorillonite(MMT)on epoxy resin was investigated by limiting oxygen index(LOI),vertical burning(UL-94),TGA,cone calorimetry(CONE)and scanning electron microscope(SEM).LOI and UL 94 test results showed that at the content of 5%IFR+1%MMT,modified EP can pass UL 94 V-0 grade,and reached 29.2%LOI value at the content of 10%IFR+1%MMT.TGA test results revealed that the incorporation of IFR/MMT into epoxy resin enhanced charring formation.The char yield of modified EP increased from 15.02 wt%to33.93 wt%at 700℃significantly.According to the cone test,heat release rate(HRR),total heat release(THR)and total smoke product(TSP)were all decreased dramatically in the modified EP.It can be also seen that av-HRR,pkHRR,and TSP of the modified EP were lowered by 52.0%,33.2%and 70.0%,respectively,in comparison with those of pure EP.Moreover,IFR/MMT helped epoxy resins to forming more homogeneous and compact char layer during combustion as seen by SEM.