缩合型阻燃硅橡胶的研制

摘要

以端羟基聚二甲基硅氧烷、气相法白炭黑、三氧化二铁、金属氢氧化物、阻燃协效剂、硫化剂等为原料，制成缩合型室温硫化（ RTV）阻燃硅橡胶。研究了氢氧化铝、氢氧化镁和阻燃协效剂对RTV阻燃硅橡胶性能的影响。结果表明，氢氧化镁比氢氧化铝有更好的阻燃效果，氢氧化镁与硅橡胶的热降解温度更匹配；阻燃协效剂与氢氧化镁并用，对硅橡胶的成炭性和阻燃效果有积极影响。较佳配方为：100份107硅橡胶、20份白炭黑、4份三氧化二铁、4份硫化剂、70份氢氧化镁、1份阻燃效剂。按此配方制得的硅橡胶的拉伸强度为2.8 MPa，拉断伸长率为241％，氧指数为40.7％，垂直燃烧等级为FV-0级。%RTV flame-retarding silicone rubber was prepared with 107 silicone rubber, fumed silica, Fe2O3, hydroxide, flame-retardant synergist and curing agent .The effects of Al(OH)3, Mg(OH)2, flame-re-tardant synergist on the RTV flame-retarding silicone rubber were investigated .Result shows that the silicone rubber filled with Mg ( OH) 2 exhibited better flame retardance , compared with that filled with Al ( OH) 3 .The thermal degradation temperature of Mg ( OH) 2 was more thermally compatible with that of silicone rubber than that of Al(OH)3.It was found that the flame-retardant synergist blends with Mg (OH)2 had a positive impact on the flame retardance and charring of silicone rubber .The optimum composition was as follows:107 silicone rubber 100 phr, fumed silica 20 phr, Fe2O3 4 phr, Mg(OH)2 70 phr, flame-retardant synergist 1 phr.The RTV flame-retarding silicone rubber had a tensile of 2.8MPa, elongation at break of 241%, OI of 40.7%, and vertical combustion of FV-0 grade.