Lignin-Reinforced Nitrile Rubber/Poly(vinyl chloride) Composites via Metal Coordination Interactions

In this work, half the mass of carbon black (CB) was replaced by lignin for preparation of high-performance nitrile rubber/poly­(vinyl chloride) composites via constructing interfacial Zn²⁺-based coordination bonds. It was demonstrated that lignin played a significant role as a natural ligand to form the Zn²⁺-based coordination interactions in the interphase between lignin and a rubber matrix. The tensile strength and Young’s modulus of the composites were significantly enhanced by the Zn²⁺-based coordination bonds owing to the dynamic fracture of coordination bonds. The thermo-oxidative aging resistance of the composites was improved by lignin and could be conveniently regulated by the content of ZnCl₂ and sulfur. The high-temperature oil resistance of the composites also benefited from the partial substitution of CB by lignin and incorporation of the metal coordination bonds. This work opens a facile method for the potential application of green lignin in rubber–plastic composites through a conventional rubber compounding process.