Rubber antioxidants

Antioxidants
Antioxidants are used to reduce aging processes in vulcanizate. They function by slowing down the deterioration of rubber produces.
Rubber antioxidants are mostly phenols and amines, and more particularly their condensation products with other compounds. Usually 1 to 2 per cent is added to a rubber formulation. The most common one is phenyl naphthylamine.
Some classical mixtures of antioxidants are available and also several proprietary products the composition of which has not been disclosed. In general, it is preferable to use mixtures as they not only protect against oxygen, but have also other desirable properties. Some of them give resistance go cracking by flexing, others provide protection against heat or light, still others protect against the detrimental effects of metals, such copper, etc.
The resistance to cracking on repeated flexing (called flex cracking) has been extensively studied. This phenomenon may be considered dynamic aging of rubber while oxidation at rest may be regarded as static aging. Finally, the best means found so far is adding waxy substances to rubber compounds. After vulcanization, these have a tendency to bloom on the surface of the rubber article, thus forming a protective film.




New Words and Expressions
1. antioxidant 防老剂
2. aging 老化
3. function 作用，功能
4. slow 尽职，起作用，有效用
5. deterioration 减慢
6. phenol 破坏，败坏
7. amine 胺
8. condensation 凝结，浓缩
9. formulation 配方
10. phenyl 苯基
11. naphthylamine 萘胺
phenyl-naphthylamine 苯基萘胺
12. classical 传统的，经典的
13. available 有用的
14. proprietary 所用的，专利的，独占的
15. disclose 公开，宣布，透露
16. preferable 较好一点的
17. protect 保护
protect…against(from) 保护……免受……之害
18. desirable 想望的，理想的
19. crack 裂缝，破裂，发生裂缝，弄出裂缝
20. flex 弯曲，伸缩
21. detrimental 有害的
22. copper 铜
23. repeat 重复
24. phenomenon 现象
phenomena 现象（复数）
25. dynamic 动态的
26. oxidation 氧化
27. rest 休息，静止，其余
at rest 静止状态
28. static 静态的
29. so far 迄今，到目前为止
30. waxy 蜡状的，蜡样的
31. tendency 趋势
32. bloom 喷霜，喷出
33. film 薄膜喷霜，喷出喷霜，喷出喷霜，