Aging test report of rubber sealThat is to say, rubber sealant is how anti-aging
The factors that cause rubber aging are:(a) oxygen, oxygen free radical chain reaction in rubber with rubber molecules, the molecular chain rupture or excessive crosslinking caused by rubber properties. The change of oxidation is one of the important reasons for the aging of rubber.(b) ozone, ozone chemical activity is much higher than the oxygen, more damaging, it is also the molecular chain was broken, but the effect of ozone on the rubber with rubber deformation and no different. As for the deformation of the rubber (mainly unsaturated rubber), and should be perpendicular to the direction of stress crack the so-called "ozone cracking"; effect on the deformation of the rubber, only surface oxide film without cracking.(c): heat temperature increase can cause rubber thermal cracking or thermal crosslinking. But the basic role of heat or activation. Improve the diffusion rate of oxygen activation and oxidation reaction, thus speeding up the rubber oxidation reaction speed, which is an aging aging phenomenon, heat and oxygen.(d) light: light is shorter, the greater the energy. The destructive effects of rubber from the high energy ultraviolet light can directly cause fracture and cross-linking of rubber chain, rubber due to absorb light energy and produce free radicals, trigger and accelerate the oxidation reaction. The ultraviolet light plays the role of heating. The other feature (light and heat effect) is its main in the rubber surface into. The gum content of high sample, both sides will appear net cracks, the so-called "light outer crack".
Knowledge about aging of rubberFirst, what is rubber aging? What are the manifestations on the surface?Rubber and rubber products in the processing, storage and use of the process, due to the comprehensive effect of internal and external factors caused by the physical and chemical properties and mechanical properties of rubber gradually deteriorated, and finally lose value, this kind of change is called aging of rubber. On the surface for cracking, sticking, hardening, softening, pulverization, discoloration, mildew etc. What are the two. And the influencing factors of rubber aging?
(E) mechanical stress in mechanical stress under the repeated action, will make the rubber chain fracture generation of free radicals, causing oxidative chain reaction, the formation of chemical process. The mechanical fracture of the molecular chain and mechanical activation. The oxidation process which can be dominant, depending on the conditions. In addition, the stress under the action of easily lead to ozone cracking.(f) the role of water: water has two aspects: rubber in the humid air or rain soaked in water, easy to damage, this is because the rubber in water soluble substances and water groups by water extraction components dissolved. By hydrolysis or absorption of reasons. Especially in the alternate action of soaking water and air exposure, will accelerate the destruction of water. But the rubber rubber is not destructive in some situations, and even delay the aging effect.(g) other: on the role of rubber and chemical factors of medium, valence metal ion, high-energy radiation, electrical and biological fields.
Three, rubber aging test methods can be divided into which categories?Can be divided into two major categories:(a) natural aging test methods are divided into atmospheric aging test, atmospheric accelerated aging test, natural storage aging test, natural media (including underground and so on) and biological aging tests(b) artificial accelerated aging test methods for thermal aging, ozone aging, light aging, artificial weathering aging, light ozone aging, biological aging, high energy radiation and electrical aging, and aging of chemical mediaFour, hot air aging test, for all kinds of rubber, what temperature grade should be selected?For natural rubber, usually test temperature of 50~100 DEG C, synthetic rubber is usually 50~150 degrees, some special rubber test temperature is higher. Such as nitrile rubber with 70~150 C, silicon and fluorine rubber is commonly used in 200~300 C. In short, should be determined according to the test.
