High-Performance All-Bio-Based Laminates Derived from Delignified Wood

Abstract

The need for renewable bio-based materials that could replace well-established synthetic composite materials is rapidly growing. For example, bio-based materials are increasingly used in applications where a lightweight design should be combined with sustainability and recyclability. However, it is often very challenging to directly transfer the excellent properties of biological materials to a product in a scalable and cost-efficient manner. In this study, we combined delignified wood layers (veneers) and a starch-based glue into bio-based high-performance composites. First, we investigated the ideal amount of starch-based glue between the layers to prevent delamination in the final composite. Then, we produced laminates in unidirectional, cross-ply, and quasi-isotropic configurations using wet processing. Laminates with tensile properties up to 40 GPa and 200 MPa in tensile stiffness and strength, respectively, were fabricated with a very high fiber volume content of up to 80%. The high fiber volume contents led to mechanical interlocks between neighboring fibers and made the need for an additional matrix unnecessary. The water-based laminate process is cost-efficient and scalable and additionally allows one to make full use of delignified wood’s formability by producing shaped parts for various applications.