Lignin-Derived Diphenylamines for Thermo-Oxidative Stabilization of Natural Rubber
- 1Guizhou Academy of Forestry, Guiyang 550005, China
- 2College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410000, China
Abstract
Sustainable polymer stabilization requires renewable antioxidants that combine efficient radical scavenging with clear structure–performance relationships. Diphenylamine antioxidants are widely used in rubber protection, but their conventional production depends on petrochemical feedstocks and hazardous aniline chemistry. Lignin valorization research largely targets model compounds; native lignin’s complexity makes direct conversion challenging. Here, we report a two-step tandem strategy that converts raw lignin into diphenylamine compounds without intermediate purification. PtFe/NiAl2O4 and phosphotungstic acid first depolymerize lignin selectively to p-substituted phenols, which are then converted into diphenylamine derivatives with ammonium formate, Pd/C and LiOH. The process affords p-substituted phenols in 35 wt% yield and final diphenylamine compounds in 23 wt% yield from birch lignin. When incorporated into natural rubber at 1 wt%, the lignin-derived diphenylamines suppress thermo-oxidative aging: after treatment at 140 °C for 24 h, the mass loss decreases from 10% for the untreated rubber to 1% for the stabilized material. The stabilized rubber also withstands harsher aging conditions and shows performance comparable to commercial EPDM rubber. Mechanistic experiments indicate that lignin demethoxylation supplies in situ hydrogen for depolymerization, while the diphenylamine N–H group interrupts radical chain oxidation in the rubber matrix. This work links lignin valorization chemistry with polymer-aging control and provides a renewable route to high-performance rubber antioxidants.
Related
- Impeller Configuration and Agitation Speed Govern Lignin Dispersion and Resultant Properties of Natural Rubber Composites in Wet Mixing: A CFD Experimental Study
- Stabilization and Carbonization of Electrospun Organosolv Lignin Fibers from Miscanthus x giganteus to Produce Biobased Carbon Fiber
- A DFT Study of Oxidative Lignin β-O-4 Bond Cleavage by Transition-Metal Catalysis
- Coarse‐Grained Molecular Dynamics Simulations of Oxidative Aging and Stabilization in Polymer Melts With Primary Antioxidants: Effects of Antioxidant Concentration and Molecular Architecture
- Advanced lignin-derived carbon aerogel for efficient uranium removal from complex mining wastewater: adsorption performance, mechanism, and thermodynamics
BibTeX
@article{wang2026ligninderived,
title = {{Lignin-Derived Diphenylamines for Thermo-Oxidative Stabilization of Natural Rubber}},
author = {Zhongwei Wang and Zhaozhuo Yu and Zhu Liu and Qinghan Zeng and Mei Luo and Yipeng Tang and Ning Ji and Wulin Yang and Shoulu Yang},
journal = {Polymers},
year = {2026},
month = oct,
doi = {10.3390/polym18202526},
url = {https://www.mdpi.com/2073-4360/18/20/2526},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Lignin-Derived Diphenylamines for Thermo-Oxidative Stabilization of Natural Rubber
AU - Zhongwei Wang
AU - Zhaozhuo Yu
AU - Zhu Liu
AU - Qinghan Zeng
AU - Mei Luo
AU - Yipeng Tang
AU - Ning Ji
AU - Wulin Yang
AU - Shoulu Yang
PY - 2026
DA - 2026/10/15
JO - Polymers
DO - 10.3390/polym18202526
UR - https://www.mdpi.com/2073-4360/18/20/2526
AB - Sustainable polymer stabilization requires renewable antioxidants that combine efficient radical scavenging with clear structure–performance relationships. Diphenylamine antioxidants are widely used in rubber protection, but their conventional production depends on petrochemical feedstocks and hazardous aniline chemistry. Lignin valorization research largely targets model compounds; native lignin’s complexity makes direct conversion challenging. Here, we report a two-step tandem strategy that converts raw lignin into diphenylamine compounds without intermediate purification. PtFe/NiAl2O4 and phosphotungstic acid first depolymerize lignin selectively to p-substituted phenols, which are then converted into diphenylamine derivatives with ammonium formate, Pd/C and LiOH. The process affords p-substituted phenols in 35 wt% yield and final diphenylamine compounds in 23 wt% yield from birch lignin. When incorporated into natural rubber at 1 wt%, the lignin-derived diphenylamines suppress thermo-oxidative aging: after treatment at 140 °C for 24 h, the mass loss decreases from 10% for the untreated rubber to 1% for the stabilized material. The stabilized rubber also withstands harsher aging conditions and shows performance comparable to commercial EPDM rubber. Mechanistic experiments indicate that lignin demethoxylation supplies in situ hydrogen for depolymerization, while the diphenylamine N–H group interrupts radical chain oxidation in the rubber matrix. This work links lignin valorization chemistry with polymer-aging control and provides a renewable route to high-performance rubber antioxidants.
SN - 2073-4360
ER -