Polysaccharide macroinitiators: An efficient pathway to synthesizing polysaccharide copolymers, and their prospects

Polysaccharides are abundant, sustainable biomaterials derived from diverse natural sources. Their low toxicity, biodegradability, and intrinsic bioactivity make them particularly attractive for food, agricultural, and biomedical applications. Tailoring polysaccharide structure can enhance their performance and broaden their range of applications. Chemical modification is an effective method for modulating polysaccharide functions and properties. Polysaccharide-based copolymers are particularly promising as they integrate the intrinsic functionality of natural polysaccharides with the structural and chemical tunability of synthetic polymers. The copolymers exhibit unique and valuable property and behavior including self-assembling, phase separation, and can serve as analogs of natural conjugates like glycoproteins. Among available synthetic routes, the macroinitiator strategy offers an efficient and potentially scalable approach to preparing polysaccharide-based block and graft copolymers. This review presents the macroinitiator strategy and introduces classical and emerging synthetic routes, including controlled radical polymerizations such as ATRP, RAFT, NMP, and ring-opening polymerizations, with particular attention to recent advances toward the green and economical synthesis of high value polysaccharide-based graft and block copolymers. The design of polysaccharide macroinitiators, polymerization advances, copolymer properties and morphologies, and their applications and potentials in nanostructured carriers, polymer blend compatibilizers, hydrogels, and lubricants are reviewed and discussed. Finally, key challenges and future directions of polysaccharide macroinitiator strategies are discussed.