Study on the aging behavior and mechanism of nitrile rubber in aviation kerosene

Based on the commonly used service environment of nitrile rubber, the mechanical properties, Shore hardness, chemical structure, and thermal stability of 5176S nitrile rubber after accelerated aging in RP-3 aviation kerosene were studied under conditions of 60 °C ∼ 100 °C. The influence of aging temperature and aging time on the properties of nitrile rubber was analyzed. The results indicate that at relatively low temperatures (below 70 °C), nitrile rubber has excellent resistance to medium aging, and its tensile properties remain stable during long-term aging. When the temperature is above 80 °C, the oxidation reaction is enhanced, and the rubber gradually changes from soft to hard and brittle. Its tensile strength and elongation at break both rapidly decrease with time and the higher the temperature is, the faster the decrease rate will be. The shore hardness of rubber shows a trend of first decreasing and then increasing. The higher the temperature is, the earlier it reaches the lowest point. During the entire aging process, the cross-linking reaction is the main reaction in the early stage, and the performance decreases slowly. In the later stage, degradation is the main focus, and the rate of performance degradation is significantly accelerated.