Recent Advances in Synthesis of Waterborne Polyurethane and Their Application in Water-based Ink： A Review

Over the last few years, waterborne polyurethane （WPU） was applied to various fibers, adhesives, primers for metals, caulking materials, emulsion polymerization media, paint additives, defoamers, associate thickeners, pigment pastes, textile dyes and biomaterials, resulting in the increasing enthu- siasm of researchers to design and synthesize novel WPU with unique properties. Thus, various processes and raw materials have been developed to prepare WPU. This review gives an overview on the de- velopments of WPU mainly derived from novel polyols, analyzes the potential application in water-based inks and presents the probable future research area about water-based inks. Notably, the poly（e-cap- rolactone） and poly（lactic acid） are the versatile materials used in WPU synthesis and supply the po- tential special performance for preparing WPU. Meanwhile, addition-fragmentation chain transfer （RAFT） polymerization and atom transfer radical polymerization （ATRP） processes provide an opportu- nity to control the chain sequence of WPU and obtain products with the desired performance.