改性埃洛石复配聚磷酸铵对硅橡胶阻燃性能和力学性能的影响

为研究埃洛石对硅橡胶阻燃性能和力学性能的影响,将埃洛石经乙烯基三甲氧基硅烷(A-171)表面改性处理后与聚磷酸胺(APP)复配并用于硅橡胶基体中,经机械共混制备了复配填充改性埃洛石(m-HNTs)的阻燃硅橡胶复合材料(FRSR)。利用红外光谱、热重分析对m-HNTs进行表征分析,采用扫描电子显微镜、极限氧指数(LOI)、垂直燃烧、锥形量热、能谱仪、热重分析等对FRSR的力学性能、阻燃性能、残渣形貌及热降解行为进行研究,并与复配填充未改性HNTs的样品性能对比。结果表明,复配填充适量的m-HNTs后,FRSR阻燃性能明显改善,力学性能显著提高。当复配填充3phr m-HNTs时,拉伸强度达8.7 MPa,LOI值达31.4%,UL-94测试为V-0级,且残渣致密紧实,热阻隔效果好,残炭率高,热释放速率降低36%。

Effects of Modified Halloysite Nanotubes and Ammonium Polyphosphate on the Flame Retardancy and Mechanical Property for Silicone Rubber

To study the effects of modified halloysite nanotubes (m-HNTs) on the flame retardancy and mechanical property for silicone rubber,the halloysite nanotubes (HNTs) modified with ethenyl trimethoxysilane (A-171) were selected to incorporate in silicone rubber together with ammonium polyphosphate (APP) to prepare flame retardant silicone rubber (FRSR) composite by mechanical blending process.The m-HNTs were characterized by FT-IR and TG.The flame retardancy,mechanical properties,morphology of residue and thermal degradation behaviors were investigated by SEM,limiting oxygen index (LOI),vertical burning test (UL-94),cone calorimetry,energy disperse spectroscopy(EDS) and TG.The results show that a substitution of a certain fraction of APP with m-HNTs can significantly improve the flame retardancy and mechanical properties of FRSR.When the content of m-HNTs is 3 phr,the tensile strength is 8.7 MPa,LOI value is 31.4％ and the UL-94 rating is V-0.Moreover,the residues are stable and compact,the heat release rate (HRR) is reduced by 36 ％.