A) Oxygen: Oxygen in the rubber reacts with the free radical chain of the rubber molecule, and the molecular chain is broken or excessively cross-linked, which causes the change of the rubber properties. Oxidation is one of the important reasons for rubber aging.

B) Ozone: The chemical active oxygen of ozone is much higher and more destructive. It also breaks the molecular chain, but the effect of ozone on rubber varies with whether the rubber is deformed or not. When used on deformed rubber (mainly unsaturated rubber), cracks that are straight in the direction of stress action, the so-called "ozone cracks"; when used on deformed rubber, only an oxide film is formed on the surface without cracking.

C) Heat: Increasing the temperature can cause thermal cracking or thermal crosslinking of the rubber. But the basic effect of heat is activation. Improve the oxygen diffusion rate and activate the oxidation reaction, thereby accelerating the oxidation reaction rate of rubber, which is a common aging phenomenon - thermal oxygen aging.

D) Light: The shorter the light wave, the greater the energy. The damage to the rubber is the ultraviolet rays with higher energy. In addition to directly causing the rupture and cross-linking of the rubber molecular chain, ultraviolet rays generate free radicals due to the absorption of light energy, which initiates and accelerates the oxidation chain reaction process. The external light plays a role in heating. Another characteristic of light action (different from heat action) is that it mainly occurs on the surface of rubber. For samples with high rubber content, there will be network cracks on both sides, that is, the so-called "optical outer layer cracked rubber particles can be divided into black rubber particles and colored rubber particles. Black rubber particles can be divided into 1-3mm black rubber particles according to the specifications. 1-2mm black rubber granules, 2-4mm black rubber granules, colored rubber granules can be divided into green rubber granules, red rubber granules, blue rubber granules, white rubber granules, brown rubber granules, yellow rubber granules and other colors of rubber particles