What are the common factors causing the aging of rubber seals?

The main factors affecting the aging of rubber seals are as follows:

1. Oxygen

Oxygen undergoes a free radical chain reaction with rubber molecules in the rubber, and the molecular chains are broken or over-crosslinked, resulting in changes in the rubber sealing properties. Chemical action is one of the important reasons for the aging of rubber seals.

2. Ozone

Ozone is much more chemically active than oxygen and is more destructive. It also breaks molecular chains, but the effect of ozone on rubber seals varies as the rubber deforms. When used on deformed rubber seals (mainly unsaturated rubber), cracks will appear perpendicular to the direction of stress, which are so-called "ozone cracks"; when used on deformed rubber, only an oxide film will be produced on the surface without cracking.

3. Hot

Increasing temperatures can cause thermal cracking or thermal cross-linking of rubber seals. But the basic role of heat is still activation. Increasing the oxygen diffusion rate and active oxidation reaction, accelerating the rubber oxidation reaction rate is a common aging phenomenon - thermal oxygen aging.

4. Light

The fewer light waves, the more energy. Higher energy UV rays can damage rubber. In addition to directly causing the rupture and cross-linking of rubber molecular chains, rubber will also produce free radicals due to absorption of light energy, thereby causing and accelerating the reaction process of the oxidation chain. Ultraviolet light acts as a heating agent. Another characteristic of light action (different from heat action) is that it mainly enters the rubber surface. For samples with high glue content, network cracks will appear on both sides, which are so-called "smooth surface cracks".

5. Mechanical stress

Under the repeated action of mechanical stress, the rubber molecular chain of the rubber seal will break, generate free radicals, cause oxidative chain reactions, and produce mechanochemical processes. Mechanical molecular chains and mechanically activated oxidation processes. Which one prevails depends on its conditions. In addition, ozone cracking is easily caused under stress.

6. Moisture

The role of water has two aspects: rubber seals are easily damaged when it rains in humid air or is soaked in water, because the water-soluble substances and clear water groups in the rubber are extracted and dissolved by water. Causes such as hydrolysis or absorption. Especially under the alternating influence of water immersion and atmospheric exposure, the damage of rubber will be accelerated. But under certain conditions, water will not damage rubber and may even slow down aging.

[DLSEALS kindly Reminder] Sealing issues? Turn to DLSEALS! As a sealing component manufacturer, we specialize in customizing sealing components, providing a full range of services from design, research and development, production, testing, and more. If you have more information you'd like to know, feel free to contact us directly. DLSEALS's product experts are dedicated to serving you!