Silicone products will age because of high-temperature cracking, and will lose performance because of solvent oil expansion! Any product will be aging, just the length of time. Silicone products have excellent anti-aging performance, in general, silicone products can remain for more than a decade of service life.

In different environments, service life is different. At the same time, different parameters cause the life of silicone products with different formulations is different. The performance of various silicone in some environments can be as long as several decades, in industrial manufacturing long-term operation, the use of some silicone parts can exert their functions between three to five years, in a high concentration of oxygen, ozone, and other conditions, silicone can hold long service life.

Now silicone products have been very common in our life, popular with fashionable and lovely silicone mobile phone covers and a variety of cool silicone parts, daily silicone ice mold, silicone gaskets, silicone tubing, and silicone plug and cap, all of them can be said to have entered into all aspects of our lives.

Silicone Rubber because of its excellent properties in all aspects. But aging without breaking is a common issue, so what happens? How to avoid it?

• Do not come into direct contact with fire or electricity.

•  After each use, use hot water to clean the silicone appliances and dry them to ensure that they are clean and dry. Pay attention to the fact that silicone products cannot be cleaned directly with corrosive detergent and should be diluted.

• Do not use sharp appliances contact silicone products and heavy pressure and strong pull appliances.

• Put silicone products in a cool and clean cabinet or box when you do not use them.

Although silicone is very good in flexibility, ductility, temperature and pressure resistance, and chemical stability, if you do not pay attention to maintenance when using it, it will also reduce its service life.

• Aging of contact media

Silicone materials used in the natural environment will be affected by moisture in the air or other conditions, such as the external insulation materials of power systems. In salt-contaminated areas, they are easily affected by salt spray. Therefore, it is necessary to conduct aging research and analyze the aging performance under such conditions. In addition, for some silicone products in contact with oil, an oil resistance test, to improve its oil resistance performance is also the focus of the practical application.

The aging behavior of silicone in different kinds of oil, the occurrence of wear is on the one hand due to the mechanical damage of aging, but also due to the degradation of the cross-linking system of materials, resulting in the production of low molecular weight substances. The presence of fluid can reduce the coefficient of friction, but it can also accelerate the chemical degradation of silicone rubber, thus accelerating the matter of wearing.

• Silicone thermal oxygen aging

NR contains a large number of unsaturated double bonds. Under the combined action of heat and oxygen, the vulcanized rubber will produce a degradation reaction, resulting in the cracking and breaking of molecular chains and cross-linked bonds, resulting in aging.

Thermal oxygen aging is a free radical reaction and oxidation reaction. Under the condition of thermal aging without oxygen, free radical decomposition will occur, and the lower the bond cleavage energy, the faster the decomposition will be. The polymer is ionized by radiation and excited at the same time when the molecule cracks and generates free radicals, and then the main chain breaks and forms crosslinking, and finally produces a variety of gases; In ultraviolet aging, molecules absorb ultraviolet rays and stimulate specific functional groups, and then decompose or decompose through energy transfer in other functional groups, and then react by generating active groups.

Silicone rubber in the open environment of aerobic high temperature mainly occurs side chain organic group oxidation decomposition reaction, resulting in silicone rubber hardening; However, in the high temperature sealed environment without oxygen, the main chain fracture reaction occurs, generating volatile cyclic polysiloxane, resulting in silicone rubber softening. At high temperatures, silicone rubber mainly oxidized side chain methyl and broke the main chain.

• Fatigue aging

Fatigue aging of silicone rubber refers to the aging phenomenon of silicone rubber products under the action of a certain frequency and periodic stress, and the molecular structure of silicone rubber materials is changed. It is the result of the activation of two main factors, namely, force and heat.

The anti-fatigue performance of natural silicone rubber is a very important performance for the vibration-damping elastic elements subjected to repeated stress. It is directly related to the failure of the vibration-damping function and the safe operation of locomotives and vehicles. Currently, it is gradually attracting the attention of researchers.

• Ozone aging

Ozone content in the atmosphere is very low. In the aging process, ozone attack silicone molecules, then silicone expands, resulting in cracks on the surface. Ozone reacts with the double bonds in silicone molecules to form molar ozonides and peroxides, which are then regenerated into ozonides. The ozonides decompose into free radicals under the action of light and heat, leading to the chain growth reaction. In addition, silicone rubber will produce molecular fracture under the action of stress but does not generate ozonides, cracking, and aging phenomenon.

Through the study of different kinds of pavement adhesives under the action of ozone, including natural silicone rubber, oil-filled methyl butadiene silicone rubber, polyisoprene silicone rubber, and butadiene silicone rubber, it is shown that the service life of silicone rubber decreases with the extension of ozone action time, and the decline is rapid in a short time of ozone action, which proves that silicone rubber has obvious degradation at the early stage of ozone action. The life of ozone decreases slowly with the extension of ozone action time. This may be due to the slowing down of the degradation process during the deepening phase of polymer decomposition.