Abstract:The chemical modification methods of lignin are mainly divided into three categories， including lignin depolymerization， synthesis of new chemically active sites， and functionalization of hydroxyl groups. These methods provide new ideas for the application of lignin in polymers. The application and research progress of lignin as agricultural material in fertilizer， plant growth regulator， and pesticide； as biomedical materials in tissue engineering and DNA delivery applications； as smart materials in biosensors and shape programmable materials were summarized in this paper.
