Wood cellulose biocomposites with fibrous structures at micro- and nanoscale

High-strength composites from wood fiber and nanofibrillated cellulose (NFC) were prepared in a semi-automatic sheet former. The composites were characterized by tensile tests, dynamic mechanical thermal analysis, field-emission scanning electron microscopy, and porosity measurements. The tensile strength increased from 98 MPa to 160 MPa and the work to fracture was more than doubled with the addition of 10% NFC to wood fibers. A hierarchical structure was obtained in the composites in the form of a micro-scale wood fiber network and an additional NFC nanofiber network linking wood fibers and also occupying some of the micro-scale porosity. Deformation mechanisms are discussed as well as possible applications of this biocomposites concept.