不同压缩比下白炭黑增强氟硅橡胶的老化性能

Aging properties of silica reinforced fluorosilicone rubber at different compression ratios

以白炭黑增强氟硅橡胶为研究对象,考察了不同的压缩率和加速老化温度下材料的压缩永久变形保留率的变化,研究了应力、老化温度等对材料压缩性能保留率的影响,采用同步热分析仪对200℃热空气加速老化环境中材料的热稳定性进行了对比分析。结果表明,相同压缩比下材料的压缩永久变形保留率随温度的升高而下降;同一温度下,压缩比越大材料的自由体积越小,相应的压缩保留率越小;相同压缩比下,温度越高分子链运动能力越强,松弛后的高度越低。热失重分析结果表明,压缩比、老化时间等对材料热性能的影响相对较小,推测是受力状态下在热空气加速老化过程中白炭黑增强氟硅橡胶的分子结构破坏程度较小所致。

The changing regularity of compression permanent set retention of silica reinforced fluorosilicone rubber was investigated at different compression ratios and accelerated aging temperatures, the effect of stress and temperature on compression performance retention were researched, and the thermal stability of rubber which were aged in a hot-air-oven at 200 ℃ was compared by a synchronous thermal analyzer. The results showed that at the same compression ratio, the compression permanent set retention decreased with increasing temperature; at the same temperature, the free volume in the rubber reduced and thus the corresponding compression performance retention decreased; at the same compression ratio, the higher the temperature, the greater the mobility of molecular chain and the lower the height of the compressed sample after it relaxed. The results of thermal gravimetric analysis indicated that the compression ratio and aging time had relatively small influence on the thermal properties, this was because that the molecular structure of silica reinforced fluorosilicone rubber was damaged slightly during hot air accelerated aging under the action of compression stress.