Combination of Primary and Secondary Antioxidants
Plastics and elastomers play a crucial role in various industries, including automotive, electronics, construction, and packaging. However, a significant drawback of these materials is their susceptibility to degradation through various forms of oxidation, leading to a deterioration of their mechanical properties. To minimize this drawback, a combination of primary, secondary, and antioxidants is often used.
Primary Antioxidants
Primary antioxidants are substances that inhibit the oxidation of plastics and elastomers. They achieve this by intercepting the oxidation process before it leads to a chain reaction. They quickly react with the free radicals generated during oxidation, forming stable compounds that prevent further oxidation.
Examples of primary antioxidants include phenols, phosphites, and amines. However, these antioxidants can volatilize at high temperatures, leading to material degradation.
Secondary Antioxidants
Secondary antioxidants are substances that support the action of primary antioxidants. They help enhance the effectiveness of primary antioxidants and extend the materials’ lifespan.
Examples of secondary antioxidants include thioethers and phosphonates. They can also serve as UV stabilizers, protecting the materials from the harmful effects of UV rays.
Antioxidant Combination
The combination of primary and secondary antioxidants offers higher efficiency than using a single antioxidant. Primary antioxidants initiate the protection process, while secondary antioxidants reinforce the effect, thus prolonging the materials’ lifespan.
Additionally, antioxidant combinations can provide other benefits, such as improved processability of the materials and enhanced color stability.
Summary
The combination of primary and secondary antioxidants provides an effective way to extend the lifespan of plastics and elastomers by inhibiting their oxidation. Primary antioxidants initiate the protection process, while secondary antioxidants enhance the effect, offering higher efficiency. The use of antioxidants in combination can also provide other benefits, such as improved processability of the materials and increased color stability.
