硅氮化合物交联的缩合型双组分室温硫化硅橡胶的热稳定性

THERMAL STABILITY OF TWO - COMPONENT CONDENSATION TYPE RTV SILICONE RUBBER CURED BY SILICON-NITROGEN CROSSLINKING AGENTS

从热失重、交联密度和溶胶量等方面研究了甲基硅橡胶用硅氮化合物作交联剂经无催化交联所得硫化胶的热稳定性,表明其耐热性比用Si(OEt)_4在催化剂存在下所得的硫化胶高150℃;前者在350℃×60h下,失重率约3％,降解反应速率常数为0.42×10^(-3)h^(-1),活化能为330kJ/mol;后者在200℃×60h下分别为8％,1.29×10^(-3)h^(-1),70kJ/mol。

The thermal stabilities of room temperature vulcanized (RTV) dimethyl silicone rubber, cured in the absence of catalyst by the novel KH-CL crosslinking agents containing silicon-nitrogen bond, were studied through the measurements of isothermal weight loss, crosslink density and the amount of soluble gel of the vulcanizates after heat aging . It was found that the thermal stability of the KH-CL-cured RTV silicone rubber was 150°C higher than that of Si (OEt)4-cured RTV silicone rubber; the weight loss, the reaction constant and the activation energy of thermode-gradation reaction of the former were about 3% (after heat aging 60 h at 350°C), 0.42 ×10-3h-1 (at 350°C),330 kJ/mol respectively, whereas those of the later were 8% (after heat aging 60 h at 200°C ), 1.29 × 10-3h-1(at 200°C ), 70 kJ/mol respectively.