Lignin nanoparticles in coatings for wood preservation

The use of wood by man has a millennial tradition and the striving for an extended shelf life of wooden products in transport or housing has therefore been an endless effort. In the industrialized eras of human history, thermal and later chemical treatment of wood became widespread. The latter gave rise to ecological problems regarding their production, but also end-use as well as the finish of their life cycle as toxic waste. In plants, various protective effects are attributed to the presence of lignin, i.e., defense when exposed to biological and environmental agents. Densely lignified wood tissue is not penetrable by microorganisms and crosslinking of polysaccharides by hydrophobic lignin prevents the wood cell walls from swelling to a certain extent in humid ambience. Different approaches to transfer this knowledge from nature to the application of lignin and lignin nanoparticles in wood coatings are reviewed in this chapter.