The chemical reaction that occurs when the barrel is exposed to sunlight is caused by multiple factors. Firstly, ultraviolet radiation, the dominant factor in photochemical reactions, can directly cause molecular chain breakage. In all light, the shorter the wavelength and the higher the energy, the more it can accelerate the aging of plastic barrels, because rubber and plastic materials produce free groups when absorbing light energy, which can trigger and accelerate some adverse chain reactions.
In addition, if exposed to light, there is usually a temperature change, which can be seen as heating. An increase in temperature will accelerate the diffusion of oxygen, thereby increasing its oxidation rate and causing thermal bonding and cracking. In addition, excessive bonding or molecular chain breakage can accelerate aging when in contact with oxygen or even ozone in the air, and there are also other factors such as water, high-energy radiation, and the medium in which it is located. So, when using plastic buckets in daily life, try not to expose them to direct sunlight.