Structural and Ecofriendly Holocellulose Materials from Wood: Microscale Fibers and Nanoscale Fibrils

Mildly delignified wood holocellulose fibers show well‐preserved cellulose nanofibril (CNF) structure in the fiber cell wall. Fibers, paper, biocomposites, and compression‐molded fiber materials demonstrate excellent mechanical properties. Here, wood holocellulose fibers and corresponding CNFs are discussed with respect to nanostructure, mechanical performance, and advanced materials potential. Functionalization routes are discussed, as well as materials selection, nanoscience of recycling, and the embodied energy in cellulosic candidates for multifunctional structural materials. Wood holocellulose fiber and nanofibrils with highly preserved native cellulose−hemicellulose structure can be obtained by mild delignification and low‐energy mechanical treatment. Corresponding fiber network materials have excellent mechanical properties, high recycling ability, low embodied energy, and facile modification routes. The processing–structure–property relationships are discussed, giving more insights into cellulosic material design with the aim of broadening their application areas.