Polymer compounds inevitably undergo aging in natural environments, with the extent primarily determined by oxygen content in the air, ambient temperature, and moisture levels. Therefore, to simulate the aging process of polymers under natural conditions, an air exchange aging test chamber must be used to provide high temperatures while maintaining specific levels of moisture and oxygen, ensuring the simulated environment closely resembles real-world conditions.
To sustain a certain water vapor and oxygen concentration within the sealed aging test chamber, air exchange with the external environment is necessary to guarantee test accuracy. The air exchange capacity is a critical parameter, as the volume of exchanged air directly impacts the aging effect of polymers inside the chamber. Typically, the air exchange in such chambers is achieved through forced ventilation, where a blower facilitates forced convection between the internal and external air. This ensures thorough circulation of hot air inside the chamber while maintaining moisture and oxygen levels. Additionally, it removes volatile substances generated during the thermal aging of polymer compounds, aligning the internal gas composition with the external environment.
Under artificial simulation conditions, a higher blower speed results in greater air exchange, enhancing internal-external circulation and convection, thereby accelerating and intensifying the aging effect. Conversely, a lower blower speed reduces air exchange, leading to insufficient air circulation and slower aging. Therefore, when conducting air exchange aging tests on high-content rubber materials, the air exchange rate should be maintained between 8 to 20 chamber volumes per hour.
Thus, the air exchange capacity is a key performance parameter of the aging test chamber. Any malfunction in this regard may introduce errors in test results. Consequently, regular verification of the air exchange rate is essential during practical use.
