氢氧化镁阻燃硅橡胶的制备及性能

Preparation and properties of flame retardant silicone rubber with Mg(OH)_2.

分别采用未处理氢氧化镁、有机硅处理氢氧化镁、硬脂酸处理氢氧化镁为阻燃剂,制备阻燃硅橡胶,研究了氢氧化镁种类对硅橡胶阻燃性能、力学性能、电性能的影响;通过扫描电镜观察阻燃硅橡胶的拉伸断面形貌,并通过热重分析对硅橡胶的阻燃机理进行初步探讨。结果表明,采用经有机硅处理的氢氧化镁为阻燃剂时,硅橡胶的阻燃效果优于采用其它两种氢氧化镁为阻燃剂的硅橡胶;有机硅处理氢氧化镁对硅橡胶的力学性能和电性能损害较小。添加60份有机硅改性氢氧化镁时,硅橡胶的极限氧指数达到36%,拉伸强度为6.4MPa,撕裂强度为32.9kN/m,邵尔A硬度为51度,体积电阻率和表面电阻率分别为5.8×1015Ω.cm和4.1×1015Ω,介电常数和介质损耗因数分别为3.43和2.34×10-2。有机硅处理氢氧化镁在硅橡胶中分散较均匀,界面结合紧密,孔洞较少。

The flame retardant silicone rubber was prepared with the addition of silicone-modified Mg(OH)_2,stearic acid-modified Mg(OH)_2 and unmodified Mg(OH)_2,respectively. The effects of three kinds of Mg(OH)_2 on flame retardant properties,mechanical and electrical properties of silicone rubber were investigated,and the flame retardant mechanism of silicone rubber with Mg(OH)_2 was studied by TG analysis. The results showed that the silicone rubber with silicone-modified Mg(OH)_2 had a better flame retardant properties than those with stearic acid-modified Mg(OH)_2 and unmodified Mg(OH)_2,and the limited oxygen index (LOI) was 36%,and the tensile strength was 6.4 MPa,the tear strength was 32.9 KN/m when the loading of silicone-modified Mg(OH)_2 was 60 phr. Silicone-modified Mg(OH)_2 showed less damage to the mechanical properties and the electrical properties of the silicone rubber than the other two kinds of Mg(OH)_2. SEM photographs showed that the uniform dispersion of silicone-modified Mg(OH)_2 in the silicone rubber and better compact adhesion between silicon-modified Mg(OH)_2. Silicone rubber and little cavities founded on the tensile fracture surface of silicone rubber. Silicone-modified Mg(OH)_2 was dispersed uniform compact interface,and less perforation.