Mikael Reichler, Samuel Rabensteiner, Ludwig Törnblom, Sebastian Coffeng, Leevi Viitanen, Luisa Jannuzzi, Tero Mäkinen, Jonatan R. Mac Intyre, Juha Koivisto, Antti Puisto, Mikko J. Alava
Abstract: Mimicking natural structures allows the exploitation of proven design concepts for advanced material solutions. Here, our inspiration comes from the anisotropic closed cell structure of wood. The bubbles in our fiber reinforced foam are elongated using temperature dependent viscosity of methylcellulose and constricted drying. The oriented structures lead to high yield stress in the primary direction; 64 times larger than compared to the cross direction. The closed cells of the foam also result in excellent thermal insulation. The proposed novel foam manufacturing process is trivial to up-scale from the laboratory trial scale towards production volumes on industrial scales.
Figure: Making wood-like foams. (A) Schematic view of the setup showing how the foam is ejected from the foaming device by the controlled air pressure to the hot plate. The linear stage moves as the foam is ejected, creating a solid rod like object that is dried by the radiant heater. (B) Close view of two rods created by two passes of the cylindrical extruder head. (C) Final foam block cut into a cube for compression testing.