航空密封级氟橡胶耐热氧环境行为试验研究
Thermo-oxidative Ageing Behaviors for the Seal-grade Fluoroelastomer
-
摘要: 通过在150℃的热氧环境下对航空密封级氟橡胶F275进行了90 d的试验。观察了氟橡胶F275在不同时间的表面形貌和拉伸断面形貌,发现其表面变得更加平整但产生了空洞,拉伸断面出现了疏松状;热重(TG)和综合热分析发现,氟橡胶F275分解温度降低5℃、说明耐热性略有降低,而玻璃化转变温度只有1℃的差别,说明没有明显变化;拉伸强度随着时间的增加而连续下降,90 d后下降了18.25%;邵尔硬度从77增大到78;扯断伸长率从180%升高到185%,试验90 d后下降了22.2%;压缩永久变形随着时间的增加而增大。试验结果表明,在150℃的热氧环境下90 d后,航空密封级氟橡胶F275仍保持密封性能。Abstract: Thermo-oxidative aging behavior of F275 rubber was studied in this paper.F275 were placed inside the thermo-oxidizing ageing chamber maximum duration 90 days, and temperature was set at 150℃.Morphologies of the sample's surface and its tension fractures of F275 were investigated.The results showed that the surface of the sample changed smoother and appeared some voids, tensile fracture changed somewhat loose after aged 90 days.The characterization results of Thermo Gravimetric and Differential Scanning Calorimeter show that thermal decomposition temperature of F275 decreased about 5℃ and glass transition temperature of F275 increased about 1℃ after aged for 90 days.Tensile strenth continuous declined with the increase of aging time, and decreased by 18.25% after aged for 90 days, hardness changed from 77 to 78, elongation percent at break changed from 180% to 185%, and decreased by 22.2% after aged for 90 days.The compression permanent deformation of F275 increased with the extension of aging time.In a word, F275 has a good resistance for 150℃, oxygen-oxidative within 90 days.