Poly (dimethyl‐methylvinyl) siloxane copolymers with different vinyl contents were synthesized and the influence in vinyl contents in such copolymers on mechanical properties , thermal properties and crosslinking densities of HTV silicone rubbers were investigated .The results indicated that the hardness of the vulcanized silicone rubbers increased with the increase in vinyl contents while the elongations at break decreased with the vinyl contents .The tensile strengths and tear strengths of the vulcanized silicone rubbers increased initially with the increase in vinyl contents ,followed by a decrease when the mass fraction of the vinyl content was higher than 0 .23% .The apparent activation energies for the thermal degradation processes increased with the vinyl contents .%制备了不同乙烯基含量的多乙烯基硅油并以其作为硅橡胶混炼的添加剂，考察了不同乙烯基含量对于热硫化硅橡胶力学性能、热性能和交联密度的影响．结果表明，硫化硅橡胶的硬度随着乙烯基含量的增加而增加，撕裂强度和拉伸强度呈现先增加后减小的趋势，而断裂伸长率则逐渐减小．当硅橡胶中乙烯基质量分数达到0．23％时，撕裂强度和拉伸强度出现最大值；随乙烯基含量增加，硫化硅橡胶的热降解活化能逐渐增大．
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