Lignin from Micro- to Nanosize: Applications

Abstract

Micro- and nanosize lignin has recently gained interest due to improved properties compared to standard lignin available today. As the second most abundant biopolymer after cellulose, lignin is readily available but used for rather low-value applications. This review focuses on the application of micro- and nanostructured lignin in final products or processes that all show potential for high added value. The fields of application are ranging from improvement of mechanical properties of polymer nanocomposites, bactericidal and antioxidant properties and impregnations to hollow lignin drug carriers for hydrophobic and hydrophilic substances. Also, a carbonization of lignin nanostructures can lead to high-value applications such as use in supercapacitors for energy storage. The properties of the final product depend on the surface properties of the nanomaterial and, therefore, on factors like the lignin source, extraction method, and production/precipitation methods, as discussed in this review.

Strategies for structuring diverse emulsion systems by using wood lignocellulose-derived stabilizers

“…There are numerous possibilities for converting lignin into chemicals and derivatives. One interesting approach to developing new materials is preparation of lignin particles, as reviewed by Beisl et al 121 and Bai et al 122 For example, alkaline lignin extracted from the residues resulting from furfural production is soluble in basic water. In acidic conditions, lignin becomes insoluble and forms particles that are an effective emulsifier for o/w Pickering emulsions.…”

Lignin for Nano‐ and Microscaled Carrier Systems: Applications, Trends, and Challenges

“…In recent years, apart from its combustion for energy, isolation of lignin originating from industrial kraft pulping processes as well as biorefinery plants producing ethanol as biofuel has seen a steady increase. Parallel to the surge in the availability of lignin, nano‐ and microscaled lignin‐based materials and state‐of‐the‐art analytical techniques that provide a more detailed understanding of the structural differences of the various lignins were developed …”

Lignin for polymer and nanoparticle production: Current status and challenges

“…In addition, lignin nanoparticles could decrease surface and interfacial tensions in mixtures of water and hydrophobic liquids and create stable Pickering emulsions . Some studies have also reported the use of lignin based products as antibacterial compounds and carbonized lignin nano fibres for energy storage in batteries …”

“…[103,104] Some studies have also reported the use of lignin based products as antibacterial compounds and carbonized lignin nano fibres for energy storage in batteries. [105,106]…”