When regenerating by drying, it is important to gradually increase the temperature to avoid abrupt drying that may cause granules to burst, thereby reducing the recovery rate.
During the regeneration of silicone through calcination, excessive temperature can cause changes in the pore structure of the silicone, significantly reducing its adsorption effectiveness and affecting its usability. For blue silicone indicators or color-changing silicone, the regeneration temperature should not exceed 120°C, as the coloring agent may gradually oxidize and lose its coloring function otherwise.
Silica gel, after regeneration, should generally be sieved to remove fine particles for even granulation.
Aging activates mechanical oxidative cracking reactions: As silicone seals deform repeatedly during the sealing process, their mechanical stress weakens the atomic valence forces in the rubber molecular chains, thereby reducing the activation energy of the oxidation reaction. The reduction in oxidation activation energy makes the oxidation cracking reaction of the rubber molecular chains easier and faster.
Silicone O-Ring Internal Heating Accelerates Oxidation Reaction: As silicone O-rings are repeatedly deformed, hysteresis occurs, generating internal friction, which leads to heat inside the rubber. This heat further accelerates the oxidation chain reaction of the rubber, contributing to its aging.
Ozone Cracking in Silicone Seals: Ozone cracking occurs during the cyclic deformation process of silicone seals. This phenomenon is more pronounced under high-temperature conditions.
Silica gel absorbs moisture and can be desorbed by heating methods such as electric furnaces, flue gas waste heat, and hot air drying. The desorption heating temperature should be controlled between 120-180°C, while for blue indicator gel, colored silica gel, and blue silica gel, it is recommended to maintain a temperature of 100-120°C.
The lifespan of silicone seals is typically influenced by three factors: mechanical force, oxidation, and ozonation. Generally, silicone seals become brittle, with the propagation of fatigue cracks accelerating. Reducing the critical fracture energy will decrease their lifespan. The main factors affecting the lifespan of specific silicone seals include the following aspects:
Aging can induce mechanical cracking reactions under the action of mechanical forces: due to the viscosity of high polymers, the relaxation process of rubber during deformation cycles does not have enough time to complete, and then it enters the next deformation cycle, causing the internal deformation and residual stress of the silicone rubber seal to continuously increase. When the stress gradient is significant, it can lead to the direct fracture of rubber molecular chains, generating free radicals, which then initiate a free radical oxidation chain reaction of the rubber under the action of oxygen.
