Effects of a novel chitosan based macromolecule antioxidant COS-GMMP on the thermo-oxidative aging of styrene-butadiene rubber/silica composites

A chitosan based macromolecule antioxidant (COS-GMMP) was prepared by using chitosan (COS), 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylphenyl) methyl-4-methylp-henyl acrylate (antioxidant GM) and 3-mercaptopropionic acid (MPA) via Michael addition reaction and acylation reaction. The chemical structure of COS-GMMP was confirmed by H-1 NMR, C-13 NMR, FTIR and elemental analysis. The anti-aging behavior of styrene-butadiene rubber (SBR)/silica with COS-GMMP, as well as the low molecule antioxidant GM, was systematically investigated by the accelerated thermal aging tests, oxidation induction time (OIT), thermo-gravimetric analysis (TGA) and hot water extraction experiments. The results revealed that COS-GMMP significantly improved the thermo-oxidative aging resistance, thermal-oxidative stability and solvent extraction resistance of SBR/silica composites more effectively than the antioxidant GM. The preeminent anti-oxidative ability of COS-GMMP for SBR/silica composites was attributed to not only the synergistic antioxidative effect among hindered phenol, amide and thioether groups, but also its high molecular weight. (C) 2021 Published by Elsevier Ltd.

Automated summary

In this study, a chitosan-based macromolecule antioxidant (COS-GMMP) was synthesized and its effects on the aging behavior of SBR/silica composites were investigated. The results showed that COS-GMMP exhibited superior performance in improving the thermal-oxidative aging resistance, stability, and solvent extraction resistance of the composites compared to the low molecule antioxidant GM.