Influence of the molecular structure of phenylamine antioxidants on anti-migration and anti-aging behavior of high-performance nitrile rubber composites

Abstract

The structure of antioxidants significantly affects the anti-migration and thermal-oxidative aging properties of nitrile butadiene rubber (NBR) composites, which are crucial for applications in aerospace, biomedical, and fuel cell stack sealing industries. The findings reveal that the migration rate of N-(4-anilino phenyl) maleic imide (MC), with a reactive double bond, is only 15.6%, exhibiting the best extraction resistance. 2,4,6-Tris-(N-1,4-dimethylpentyl-p-phenylenediamino)-1,3,5-triazine (TMPPD), with a greater weight and dendritic structure, follows at 47.7%, while N-isopropyl-N′-phenyl-p-phenylenediamine (4010NA) performs the worst, with 77.8%. Furthermore, after thermal-oxidative exposure, the cross-link density of NBR composites increases, generating oxygenated substances, such as ethers, aldehydes, and acids. The addition of antioxidants in the composites improves the thermal-oxidative aging properties compared to those without any antioxidants. Moreover, antioxidants 4010NA and TMPPD display superior resistance to thermal-oxidative aging properties compared to antioxidant MC.

Keywords

• nitrile rubber
• antioxidant
• chemical structure
• solvent extraction resistance
• thermal-oxidative aging