Many items can not be used for a long time the main reason is not good use, and coupled with the different conditions, the degree is not the same, so need to find out the specific reasons for sealing ring aging, and the use of appropriate precautions, so that the time can be extended.
Reasons for aging of silicone rubber sealing rings:
1, oxygen role, oxygen in the rubber with the occurrence of free radical chain lock reaction, the occurrence of molecular chain rupture or excessive cross-linking, resulting in silicon rubber product performance changes, oxidation is one of the important reasons for aging rubber.
2, the reason of light, the shorter light waves, the greater the energy. The damage to rubber is the high energy of ultraviolet rays. In addition to directly causing the rupture and cross-linking of the rubber molecule chains, the ultraviolet ray generates free radicals by absorbing light energy, and triggers and accelerates the oxidation chain reaction process. By the outside light of the role of heating, light role of the director of another feature (unlike thermal effect) is it mainly in the surface of the rubber, with high adhesive rate of specimen, the two sides will appear mesh cracks, the so-called "light outer layer".
3, ozone role, ozone chemical reactive oxygen is much higher, more destructive, it is also caused by the molecular chain rupture, but the role of the ozone in the rubber deformation of the situation is different. As the rubber used for deformation (mainly unsaturated rubber), there is a direct crack in the direction of stress action, that is, the so-called "ozone cracking", for the deformation of rubber, only the surface of the formation of oxidation film without cracking.
Ozone aging test can be used to investigate the extent of ozone damage to silicone rubber seal ring, the test device is sealed ozone aging box, ozone generator, through the mercury lamp to produce a certain concentration of ozone. The test specimen accepts a certain tensile deformation, after a certain period of time to observe the surface crack depth, judging the anti-ozone level of the rubber material.
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