Rubber tips: why does rubber age? | OEM Products
People get old and rubber gets old. Rubber with a long time, some will become soft sticky, some will harden brittle. In daily life, we often see a lot of cracks on the side of some used tires, which are called cracks in professional.
In this case, the original elasticity and strength of rubber decrease significantly, which is called aging. Aging is the result of the change of rubber structure under the influence of various external factors, and the most common one is the thermal oxidative aging under the action of heat and oxygen. It has been proved more than 100 years ago that rubber aging is completely caused by oxygen, while heat, light and metal are accelerators of rubber aging.
When the rubber is heated to a certain temperature, it will degrade. For example, natural rubber will decompose into low molecular substances when it is over 200 ℃. The thermal stability of rubber mainly depends on its chemical composition and structure
The thermal stability of silicone rubber and fluororubber is better than that of general rubber. The thermal stability of cis-1,4-polybutadiene rubber was the best, followed by styrene butadiene rubber. In the presence of oxygen, the aging results of various rubbers are different. In the process of thermal oxidative aging, the macromolecular chains of natural rubber, isoprene rubber and butyl rubber break and become soft and sticky; The products of styrene butadiene rubber, cis-1,4-polybutadiene rubber, nitrile butadiene rubber and ethylene propylene diene monomer are interwoven in the process of thermal oxidative aging, which destroys the elastic structure of rubber and makes it hard and brittle. The root cause of thermal oxidative aging of rubber lies in its unsaturated bond.
Natural rubber and some general synthetic rubber contain 150-250 double bonds per 1000 carbon atoms. These parts are most prone to chemical reactions, so their thermal oxidative aging properties are not good, especially natural rubber. However, silicone rubber, fluororubber, butyl rubber, ethylene propylene rubber, polyurethane rubber and acrylate rubber with saturated structure are heat-resistant aging elastomers.
Although the aging of rubber can not be completely avoided, it can be delayed. The most convenient and effective measure is to add antioxidant. There are many kinds of antioxidants, including amines and phenols. For example, antioxidant h can capture the active substances produced in the thermal oxidative aging process of rubber, so as to protect the rubber. RSL rubber company has a professional technical team, through their superb technology, they can perfectly solve the aging problem of rubber products in harsh environment.
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