How Do Antioxidants in Plastics Work?
One of the greatest benefits of using plastics is their longevity. However, when certain polymers are placed under unfavourable conditions, such as extreme heat or exposure to certain chemicals, they can break down at an accelerated rate. For plastics used in automotive injection moulding and thermoforming, we use plastics with added antioxidants to improve their longevity and durability.
How do the antioxidants in plastics work?
This is where antioxidants come into play. Antioxidants neutralise the free radical molecules that accelerate oxidation and cause damage. You may have heard that antioxidants are good for your health - vitamin C, beta carotene and lycopene are examples of powerful antioxidants found in food that we can eat to slow down the attack of free radicals on our cells. If you dip an apple slice in lemon juice, it won't turn brown as quickly because the vitamin C slows down the oxidation process and I neutralises the free radicals.
Antioxidant 1010
Types of antioxidants
There are two main types of antioxidants used in plastics.
Primary antioxidants. Known as "chain-breaking antioxidants", they are free radical scavengers that scavenge alkyl radicals and hydroxyl radicals produced by abstracting hydrogen when polymer chains break at high temperatures; examples include hindered phenols.
Secondary antioxidants. These antioxidants remove organic hydroperoxides, which are formed when free radicals are removed by primary antioxidants. If not removed, hydroperoxides can cause new free radical reactions. Examples include phosphites and thioethers.
Often, a mixture of primary and secondary antioxidants work together to achieve superior processes. In injection moulding, phosphite stabilises the plastic during melting, while thioethers are ideal for plastics that are frequently exposed to heat during use.
Anti-ozone agents also prevent and slow down ozone-induced degradation of polymers. This is more likely to affect rubber, as ozone can cause rubber to crack, but it may also affect plastics.
Antioxidant 626 CAS 26741-53-7
Advantages of plastic antioxidants
Plastic antioxidants have been widely used in plastics. Polyolefins and ABS are the most used, followed by POM, PVC and nylon. The use of two or more antioxidants should be considered at the same time to produce the advantages of additive or synergistic effects to obtain better results.
1. Additive effect: The main antioxidant and the auxiliary antioxidant, when used together, bring out their respective characteristics and are better than using them alone. The use of high concentrations of antioxidants can cause side effects. But when several low concentrations of antioxidants are taken out, the side effects can be prevented and can also have a superimposed effect.
2. Synergistic effect: When antioxidants are used properly, their combined performance can exceed the effect of their individual use. It is known as the synergistic effect.
Antioxidant 1076 Cas 2082-79-3
Finally, the stability to oxygen varies between different plastics, so some plastics do not have antioxidants added. Others must have antioxidants added. Plastic antioxidants are used to trap the activity of free radicals and thus interrupt the chain reaction. Their purpose is to slow down the oxidation process and the rate of plasticisation. By the mechanism of action of antioxidants, it can affect all plastics.
Want to find out more about our plastic antioxidants? Please contact the Jinan Forever Chemical team by email or phone.
One of our representatives will be happy to discuss your needs and provide you with data that will help you make an informed decision.
评论
发表评论