Why do we need antioxidants for rubber composites?

Therefore, for a real application, the antioxidants are indispensable to retard the thermal-oxidative-aging process of the rubber composites and then prolong the service life. In this review, we systematically review the recent progress of antioxidants for rubber.

How does rubber antioxidant work?

To prolong the service life of rubber composites by retarding their aging processes, rubber antioxidant initially relies on the use of a coating, such as paraffin, and coal tar, to physically isolate oxygen, but this protective layer would quickly lose the utility due to wear.

Which antioxidants are used in rubber vulcanization?

The amine and phenolic antioxidants are the most widely used rubber antioxidants (Fig. 1 b and c). Generally, the phenolic antioxidants have poor antioxidative efficiency (compared to amine antioxidants) and they can delay vulcanization, but they cause little discoloration problems.

What are the future trends of rubber antioxidants?

The perspectives on the future trends of rubber antioxidants have been presented. Elastomers, especially diene-rubbers containing unsaturated double carbon bonds in the main chains, are vulnerable to thermal/oxygen aging, which would make the elastomers less elastic and result in earlier failure of the elastomer products.

Can rubber antioxidants contain rare-earth ions?

The recently reported rubber antioxidants containing rare-earth ions are summarized in Fig. 4, for instance, Sun et al. prepared a novel hindered phenol rare-earth complex (DTSm) (Fig. 4 f) by a simple and green method using 3,5-di-tert-butyl-4-hydroxybenzoic acid (DT) and samarium chloride hexahydrate (SmCl 3 ·6H 2 O) via coordination reaction.

Are rubber antioxidants a rational design?

The development of medical antioxidants also inspires the rational design of rubber antioxidants. Recently, Sun, et al. synthesized a novel antioxidant (APPT) containing aromatic amine, thiourea and allyl groups by the reaction between N-phenyl-p-phenylenediamine and allyl isothiocyanate (Fig. 3 b) .