磷腈类衍生物改性磷酸锆的合成及其复配聚磷酸铵对硅橡胶阻燃性能和力学性能的影响

利用原位插层反应制得磷腈类衍生物修饰的改性磷酸锆(F-ZrP),并用机械共混工艺制得阻燃硅橡胶复合材料(FRSR).采用X射线衍射(XRD)、透射电子显微镜(TEM)、傅立叶红外光谱(FTIR)、热重(TG)、扫描电子显微镜(SEM)分别对磷酸锆的结构及其在硅橡胶基体的分散进行表征,并结合FRSR的垂直燃烧(UL-94)、极限氧指数(LOI)、锥形量热测试及残渣表面形貌的观察,研究了不同份数的F-ZrP复配聚磷酸铵对FRSR阻燃性能的影响并和添加未改性磷酸锆的样品性能对比,并对阻燃机理进行初步探讨;最后分析FRSR的力学性能.结果表明:F-ZrP拥有更大的层间距,而且在FRSR中分散的更好;当1 phr F-ZrP和19 phr APP复配使用时,UL-94达V-0级且LOI值为31.4,热释放速率峰值为265.3 kW/m~2,拉伸强度达8.11 MPa,FRSR的阻燃性能和力学性能得到明显的改善.适量的F-ZrP和APP复配使用能在气相和固相发挥协效阻燃作用,F-ZrP与APP的并用能提高残渣质量并且使阻隔层更加紧实,致密.

Synthesis of Phosphazene Derivative Modified α-Zirconium Phosphate and Its Effect on the Flame Retardancy and Mechanical Properties of Silicone Rubber in Combination with Ammonium Polyphosphate

A novel functionalized α-zirconium phosphate (F-ZrP) was synthesized by phosphazene derivative via in situ intercalation,modified by dicyandiamide (DICY),and then combined with hexachlorocyclotriphosphazene (HCCP) through nucleophilic substitution and further reacted with excessive DICY.Flame retardant silicone rubber composites (FRSR) were prepared via incorporation of F-ZrP and ammonium polyphosphate (APP) with silicone rubber by mechanical blending.The structure of F-ZrP and its morphology in silicone rubber were tested by X-ray diffraction (XRD),transmission electronic microscopy (TEM),thermogravimetric analysis (TGA),Fourier transform infrared spectroscopy (FTIR) and scanning electronic microscopy (SEM).The results show that the interlayer spacing of F-ZrP was larger compared with that of α-ZrP and phosphazene derivative efficiently combined with α-ZrP.F-ZrP existed with a structure of the intercalated components in FRSR.The effect of F-ZrP on the thermal stability and flame retardancy of FRSR in combination with APP was studied by TGA,vertical burning test (UL-94),limiting oxygen index (LOI) and Cone calorimeter test.TGA results illustrated that an optimal F-ZrP content could improve the thermal stability and char residue.The addition of F-ZrP to FRSR increased the LOI value and enhanced the UL-94 rating.When the total content of the flame retardants was 20 phr and the mass ratio of F-ZrP to APP was 1:19,LOI value of FRSR was increased from 30.0 to 31.4,UL-94 rating was enhanced to V-0,and the peak heat release rate was 265.3 kW/m2.The morphology and structure of the char residue were characterized by SEM.The results suggested that the combination of F-ZrP and APP could make the char residue more stable,compact,and continuous,delaying therefore the volatilization of the decomposition product and inhibiting underlying FRSR from contacting heat and oxygen.These results indicated that there was a synergistic flame retardancy effect in gas phase and condensed phase between F-ZrP and APP for FRSR.Moreover,the mechanical properties could be reinforced with an appropriate content of F-ZrP.