脲基含氢硅树脂对室温硫化硅橡胶耐热性能的影响

以六甲基二硅氧烷、四甲基二硅氧烷、正硅酸乙酯、γ-脲丙基三甲氧基硅烷为主要原料合成脲基含氢硅树脂(UHMQ),并将其加入到乙烯基硅橡胶中作为耐热助剂,考察了UHMQ用量对室温硫化硅橡胶耐热性能及力学性能的影响。结果表明,当UHMQ的用量为8份时,硅橡胶复合材料的初始分解温度最高可达414.79℃。当UHMQ的用量为6份和8份时,在200,300,400℃下热空气老化24 h硅橡胶复合材料的质量损失率明显下降,且热空气老化24 h后仍保持一定弹性。UHMQ的加入可提高硅橡胶复合材料的力学性能,当UHMQ的用量为6份时,硅橡胶复合材料的剪切强度达到最大值。

Effect of urea based hydrogen containing silicone resin on silicone rubber curing at room temperature

Urea based hydrogen containing silicone resin(UHMQ) was synthesized using hexa-methyldisiloxane, tetramethyldisiloxane, tetraetho-xysilane and γ-urea propyltrimethoxysilane as main raw materials, and it was added to vinyl silicone rubber as heat-resistant additive. The effect of UHMQ amount on heat resistance and mechanical properties of silicone rubber curing at room temperature was investigated. The results showed that when the amount of UHMQ was 8 phr, the initial decomposition temperature of silicone rubber composites could reach 414.79 ℃. When the amount of UHMQ was 6 phr and 8 phr, the mass loss rates of the silicone rubber composites were obviously decreased after 24 h hot air aging at 200, 300, 400 ℃, and it remained elasticity after 24 hours hot air aging. The addition of UHMQ could improve the mechanical properties of the silicone rubber composites. When the amount of UHMQ was 6 phr, the shear strength of the silicone rubber composites reached the maximum value.