Manufacturing of biocomposite sandwich structures using mycelium-bound cores and preforms

摘要

A non-traditional approach to manufacturing biocomposite sandwich structures is introduced where all materials are naturally derived including natural fiber textile (jute, hemp and cellulose) as skin; mycelium-bound agricultural waste as core; and a bioresin as matrix. This paper focuses on issues related to three specific steps of the seven-step manufacturing process pertaining to assembly of the sandwich construction. Specific process details highlighted include design and thermoforming of growth trays, tray sterilization, filling trays with mycelium-inoculated substrates filling and allowing growth to occur, and, finally, conduction and convection drying/inactivation of the grown parts. To better understand how choice of skin material and processing conditions affect part performance, dried specimens with dimensions and test conditions per ASTM standards were tested in flexure by three-point bending method to determine the stiffness and strength of the resinless preforms and to identify optimal material combinations. Core and preform strength appears to depend on the degree of fungal colonization within the skin and bonding between the skin and core and is substrate dependent. As the fungal mycelium used for these experiments clearly preferred flax reinforcement for biological reasons, strength was significantly higher than the other two skin materials. Stiffness, however, is dominated by core strength. (C) 2017 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.