Lignin-based polymers via graft copolymerization

Lignin is an important source of synthetic materials because of its abundance in nature, low cost, stable supply, and no competition to the human food supply. Lignin, a cross-linked phenolic polymer, contains a large number of aromatic groups that can be used as a substitute for petroleum-based aromatic fine chemicals. However, modification of lignin is necessary for its application in advanced materials due to its chemically inert nature and structural complexity. Polymeric modification of lignin via graft copolymerization represents an important avenue for modification because this method forms stable covalent bond linkages between lignin and synthetic functional polymers. In this review, we discuss recent synthetic strategies toward polymeric modification of lignin using graft copolymerization and the special properties and applications of the produced lignin copolymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3515–3528