Lignin

one of the most abundant biopolymers on earth

is a polyphenolic macromolecule which is comprised of 9-carbonphenol propane units (p-coumaryl alcohol

coniferyl alcohol

and sinapyl alcohol) linked together by different types of bonds. Large amounts of lignin have been generated by the pulp and paper industry through kraft process. Lignin is mainly used as a low-grade fuel and its potential is not fully valued. It is economically and environmentally desirable to convert lignin to valuable reinforcing additives for rubbers. Lignin can be used as coupling agent

antiaging agent

fire retardant as well as reinforcing agent

and it could partially replace carbon black in the rubber composites. Modification of lignin

various preparation methods of rubber/lignin composites and recent research progress are systematically reviewed in this article. Lastly

the challenges and future potentials of rubber/lignin composites are proposed.