High-Performance All-Bio-Based Laminates Derived from Delignified Wood
Marion Frey, Livia Schneider, Hajar Razi, Etienne Trachsel, Eric Faude, Sophie Marie Koch, Kunal Masania, Peter Fratzl, Tobias Keplinger, Ingo Burgert
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.