硅烷偶联剂对阻燃硅橡胶性能的影响

Effect of Silane Coupling Agent on Properties of Flame Retardant Silicone Rubber

采用硅烷偶联剂作为增容剂改性热硫化硅橡胶/氢氧化铝阻燃体系,并研究了硅烷偶联剂对热硫化硅橡胶/氢氧化铝共混体系相容性、阻燃性及力学性能的影响。研究发现,硅烷偶联剂的加入可显著改善氢氧化铝在热硫化硅橡胶中的分散效果,起到增容作用,改善硅橡胶的力学性能。A-151和R-75M由于其分子结构中均含有不饱和键,对胶料性能影响结果类似,除改善氢氧化铝分散性同时还会提高胶料的交联密度,胶料的拉伸强度从4.02 MPa分别提高至7.8 MPa和7.05 MPa,邵尔A硬度从60度提高至68度和71度,但同时胶料的拉断伸长率从387%降至261%和223%。A-10E在体系中仅起到增容剂的作用,在提高胶料拉伸强度的同时还有助于提高胶料的拉断伸长率。由于氢氧化铝在硅烷偶联剂的作用下均匀分散于胶料基体,有利于改善胶料的阻燃性,但同时增加了胶料的门尼黏度。

The flame retardant system of high temperature vulcanized(HTV)silicone rubber/aluminum hydroxide was modified by silane coupling agent as compatibilizer.The effects of silane coupling agent on the compatibility,flame retardancy and mechanical properties of the blends of silicone rubber and aluminum hydroxide(ATH)were studied.The result indicates the silane coupling agents can improve the compatibility between HTV silicone rubber and ATH,which significantly improve the dispersion of aluminum hydroxide in HTV silicone rubber and improve the mechanical properties of silicone rubber.Both A-151 and R-75 M have similar effects on the properties of the silicone rubber due to the unsaturated bonds in their molecular structures.Besides,the crosslinking density of the silicone rubber is increased,while the dispersion of ATH is improved.The tensile strength of the silicone rubber increases from 4.02 MPa to 7.8 MPa and 7.05 MPa respectively,the hardness increase from 60 to 68 and 71 shore A,respectively,however the elongation decrease from 387% to 261% and 223%,respectively.A-10 E only is a compatibilizer,it also improves the tensile strength and elongation at break of the rubber.The flame retardant of the silicone rubber is improved as ATH uniformly dispersed in HTV silicone rubber with silane coupling agents,meanwhile the Mooney viscosity of the silicone rubber is increased.