Phosphorylation of nanocellulose: State of the art and prospects

Phosphorylation of nanocellulosic materials is a recently studied chemical or enzymatic treatment in which phosphate, phosphite, or phosphonium salt moieties are incorporated into the cellulosic backbone. It is possible to convert native celluloses into individual fibers that are nanometric in dimensions (∼3 nm) with a high aspect ratio (>100) and a high surface charge through phosphorylation treatment. The presence of anionically charged phosphate groups on the surface of the fibers reduces clogging and energy consumption (0.6 MWh/t) during mechanical treatment as well as improves nanocellulose dispersion in water. This paper reviews the preparation routes and fundamental characteristics of phosphorylated nanocellulose. The potential applications of phosphorylated nanocellulose include exterior wall insulation, vehicle interiors, protective clothing for firefighters and spacesuits, food packaging, bone scaffolding, adsorbents, flame retardants, and the heterogenization of homogeneous catalysts, are also introduced. Finally, the development trend and prospects of phosphorylated nanocellulose are included.