Graft modification of lignin-based cellulose via enzyme-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and free-radical coupling

In this study, a green approach combining enzyme-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and free-radical coupling was developed for the modification of jute fiber , which is a typical lignin-based cellulose. Jute fiber surface was covered by rich amount of lignin, which offered great opportunities for further functional modification. The controlled polymerization of vinyl monomers , acrylamide (AM) or butyl acrylate (BA), was carried out by horseradish peroxidase (HRP)-initiated RAFT to form well-defined polymers with well-controlled molecular weights and structures. Enzymatic grafting by HRP occurred between the free radicals of well-defined polymers and free radicals of lignin on jute. Gel permeation chromatography (GPC) analysis indicated the alkyl chain length of polymers prepared via HRP-initiated RAFT polymerization was well-controlled. Other results of flourier transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed that well-controlled alkyl chains prepared via enzymatic catalysis were grafted on the exposed lignin of jute. The study explores a new and eco-friendly modification method for lignin-based materials with the controlled graft chain structure via two different catalysis with HRP.