Fluoroelastomer Seals (Fluoroelastomer Seals) will experience thermal oxygen aging under high temperature and oxygen environment, which will lead to the deterioration of their performance and affect their service life. This paper will discuss in detail the mechanism of thermal oxygen aging of fluorine rubber oil seal, and introduce the corresponding protective measures.
1. Hot oxygen aging mechanism
Thermal oxygen aging refers to the degradation of material properties due to oxidation reaction under high temperature and oxygen environment. The thermal oxygen aging mechanism of fluorogel oil seal mainly includes the following aspects:
Oxidation reaction: At high temperatures, unsaturated bonds in fluororubber molecules are easy to react with oxygen to generate peroxides and free radicals. This oxidation reaction causes the molecular chains to break and the material to harden and become brittle.
Free radical generation: The free radicals generated during oxidation can further trigger a chain reaction and accelerate the degradation of the material. These free radicals attack the C-H bonds in the molecular chain, leading to the break of the molecular chain and the destruction of the cross-linked network.
Crosslinked network fracture: With the oxidation reaction, the crosslinked network of fluororubber gradually breaks, the strength and elasticity of the material decline, and eventually lose the sealing function.
Chemical bond break: Chemical bond break in high temperature and oxygen environment will also cause the filler in the material to lose its role, further accelerating the degradation of the material's performance.
2. Aging evaluation method
In order to evaluate the thermal oxygen aging properties of fluorinated rubber oil seals, the commonly used evaluation methods include the following:
Thermogravimetric analysis (TGA) : The thermal stability of a material is analyzed by measuring its weight loss at different temperatures. TGA can help determine the decomposition temperature and rate of a material at high temperatures.
Dynamic Mechanical Analysis (DMA) : Evaluate the degree of aging of a material by measuring its dynamic mechanical properties, such as the energy storage modulus (E ') and the loss modulus (E '). DMA can reflect the mechanical properties of materials after thermal oxygen aging.
Infrared spectral analysis (FTIR) : The use of infrared spectral analyzer to detect the change of chemical bonds in the aging process of materials to determine the type and content of oxidation products. FTIR can provide information about the oxidation process.
Hot oxygen aging test: accelerated aging test is carried out in high temperature and oxygen environment to simulate the actual conditions of use and evaluate the aging behavior and life of fluorine rubber oil seal. Thermal oxygen aging test can provide visual aging data.
3. Protective measures
In order to extend the service life of the fluorine rubber oil seal and reduce the influence of thermal oxygen aging, the following protective measures can be taken:
Antioxidant addition: Adding antioxidants to fluororubber, such as hindered phenols, phosphite esters, etc., can effectively capture free radicals and inhibit the occurrence of oxidation reactions. Antioxidants can significantly delay the aging process of the material and improve its thermal stability.
Adding heat stabilizer: Adding heat stabilizer, such as vulcanizing agent, mercaptan, etc., can improve the heat resistance of the material and reduce the molecular chain break and cross-linked network damage at high temperatures.
Surface coating: Coating the surface of the fluorine rubber oil seal with anti-oxidation coating, such as silicone coating, polytetrafluoroethylene (PTFE) coating, etc., can effectively isolate oxygen, reduce the direct contact between the material and oxygen, and delay the occurrence of oxidation reaction.
Reasonable design: In the design process of fluorine rubber oil seal, reasonable selection of materials and structural design to avoid its long-term exposure in high temperature and high oxygen concentration environment, reduce the risk of thermal oxygen aging.
Regular inspection and maintenance: Regular inspection and maintenance of the fluorine rubber oil seal, timely detection and treatment of aging problems, to ensure that it maintains good performance during use.
Step 4 Summarize
The thermal oxidation aging of fluorinated rubber oil seal is a complex process involving oxidation reaction, free radical generation and molecular chain breakage. Through the scientific evaluation method and effective protective measures, the thermal oxygen aging of the fluorine rubber oil seal can be significantly delayed and its service life can be extended. In the future, with the continuous progress of material science and engineering technology, the anti-aging properties of fluorine rubber oil seals will be further improved to meet more stringent application requirements.
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