耐热型热硫化混炼胶的研制

以甲基乙烯基硅橡胶为生胶,添加气相法白炭黑、耐热添加剂等制得耐热型热硫化硅橡胶,研究了生胶中羟基含量、白炭黑种类、白炭黑处理剂种类以及耐热剂种类对硅橡胶耐热性能的影响。结果表明,当采用羟基质量分数≤15×10^-6、乙烯基摩尔分数为0.19%的甲基乙烯基硅橡胶生胶时,其抗降解表现更好;不同类型白炭黑在不同的老化温度下对硅橡胶的影响不同,225℃及以下温度条件下,亲水型白炭黑的耐热效果优于疏水型白炭黑,225~300℃及以上温度条件下,疏水型白炭黑更优;在白炭黑处理剂对硅橡胶耐老化影响方面,采用聚二甲基二苯基硅氧烷RP140PH比常规低黏度羟基硅油和六甲基二硅氮烷更好;耐热剂对硅橡胶体系耐老化效果提升极为明显,其提升效果由高到低依次为AD105、AD111、AD104、AD110。

Preparation of Heat Vulcanized Compounds with Thermal Resistance

The heat-resistant HTV silicone rubber was prepared by methyl vinyl silicone rubber(VMQ)as raw rubber,adding silica aerogel,heat-resistant additives,etc.The influence of hydroxyl content in VMQ,silica treated in various methods,and different heat-resistant agents on the heat-resistant properties of silicone rubber was studied.Results show that the degradation resistance of silicone rubber is better when VMQ hydroxyl content(mass fraction)≤15×10^-6 and the mole fraction of vinyl is 0.19%.Different types of silica have different effects on silicone rubber at different aging temperatures:temperature≤225℃,hydrophilic silica is better than hydrophobic silica on the heat resistance;under the temperature of 225-300℃ and above,hydrophobic silica is better.In terms of the influence of silica plasticizer on the aging resistance of silicone rubber,the use of polydimethyldiphenylsiloxane RP140PH is better than that of conventional low viscosity hydroxy silicone oil and HMDZ.The heat-resistant agent significantly improves the aging resistance of silicone rubber,among which the anti-aging performance ranking from superior to inferior is AD105,AD111,AD104,AD110,respectively.