Abstract
Wood flour is an abundant wood waste from timber-based industries, but is of low value and is a hazard. To improve the sustainability of these industries and increase the intrinsic value of wood waste, there is merit in valorising it by incorporating mycelium to fabricate mycelium-bound composites. Such composites are known sustainable alternatives to conventional materials such as particle boards and polystyrene foams. In this study, an ink utilizing bamboo wood flour and bentonite that can support mycelium growth was developed to fabricate complex structures using extrusion-based 3D printing. The resulting ink could be printed into scalable structures with length scales ranging in order of magnitude from millimetres to centimetres. The presence of solid particles reduced shrinkage to 30.4 ± 5.2% when dried in oven. The presence of mycelium increased the compressive Young's modulus and ultimate strength by 756 ± 424% and 139.1 ± 34.3% respectively, the contact angle by 72.2 ± 10.2%, the thermal insulation by 30.2 ± 1.3% and the resistance to natural weathering of composites when exposed to tropical conditions over 28 days. Using 3D printing, complex structures with improved thermal insulation could be fabricated, where the design of the shape has a greater contribution than the presence of mycelium. This shows the potential for sustainable upcycling of wood waste to fabricate complex structures that can be tailored to meet the needs of various applications.