During the actual use of silicone rubber materials, they will inevitably be affected by various environmental factors and thus undergo aging phenomena. During the aging process, the dynamic mechanical properties of silicone rubber change significantly. In-depth research on these change laws is of great significance for accurately evaluating the service life and reliability of silicone rubber materials.

Under thermal aging conditions, the thermal motion of silicone rubber molecular chains intensifies, and the interactions between molecular chains gradually change, thus leading to changes in its dynamic mechanical properties. As the aging time extends and the temperature rises, the storage modulus (E') and loss modulus (E'') of silicone rubber will show different change trends. Initially, due to the thermal cross-linking reaction of molecular chains, the storage modulus of silicone rubber may increase, indicating an increase in material rigidity. However, when the aging time is further extended, thermal oxidation causes the molecular chains to break, reducing the molecular weight of silicone rubber. At this time, the storage modulus will gradually decrease, and the material becomes softer. The loss modulus reflects the energy loss of the material during deformation. During the thermal aging process, the loss modulus first decreases slightly as the cross-linking reaction proceeds, and then gradually increases as the molecular chains degrade. This is because in the initial stage of cross-linking, the constraints between molecular chains are enhanced, reducing energy loss; while after the molecular chains break, the movement of molecular chains becomes more free, increasing energy loss. Through dynamic mechanical analysis (DMA) technology, the changes in the storage modulus and loss modulus of silicone rubber during the thermal aging process can be monitored in real-time, providing intuitive data support for studying the thermal aging mechanism.
In terms of photoaging, ultraviolet irradiation is one of the main factors causing the aging of silicone rubber. Ultraviolet rays have high energy and can break the chemical bonds in silicone rubber molecular chains, triggering free radical reactions. During the photoaging process, the dynamic mechanical properties of silicone rubber also change significantly. As the illumination time increases, both the storage modulus and loss modulus of silicone rubber show a downward trend. This is because photooxidation breaks the molecular chains, reducing the molecular weight and deteriorating the mechanical properties of the material. At the same time, photoaging also causes changes in the glass transition temperature (Tg) of silicone rubber. Due to the degradation of molecular chains and changes in structure, the glass transition temperature usually shifts to a lower temperature. Through the study of the dynamic mechanical properties and glass transition temperature of silicone rubber during the photoaging process, the influence mechanism of photoaging on the microstructure and macroscopic properties of silicone rubber can be deeply understood, providing a theoretical basis for the development of anti-photoaging silicone rubber materials.
In addition, environmental factors such as humidity and oxygen also affect the aging process and dynamic mechanical properties of silicone rubber. In a humid and hot environment, the synergistic effect of water and oxygen accelerates the aging process of silicone rubber. Water molecules may penetrate into the interior of silicone rubber, promoting the hydrolysis reaction of molecular chains, and at the same time, oxygen participates in the oxidation reaction, further destroying the molecular chain structure. In this case, the changes in the dynamic mechanical properties of silicone rubber are more complex, the decline rates of the storage modulus and loss modulus are faster, and the service life of the material is significantly shortened. Studying the evolution law of the dynamic mechanical properties of silicone rubber under the synergistic action of different environmental factors is of great significance for accurately evaluating the performance changes of silicone rubber in actual complex environments and helps to formulate corresponding protective measures and service life prediction models.



3120 Phenyl Methyl Vinyl silicone Gum