Improvement of mechanical properties of mycelium/cotton stalk composites by water immersion
Ru Liu, Xiaoyan Li, Ling Long, Yan Sheng, Jianfeng Xu, Yanxia Wang
Abstract
A kind of novel sustainable mycelium/cotton stalk composite were prepared in laboratory by growing white rot fungus of Ganoderma lucidum on cotton stalk and stored in a block mold followed by hot-pressing process. To improve the mechanical properties, the composites were, respectively, subject to water immersion prior to hot-pressing at various water uptake (20%, 30%, 40% and 50%). The mechanical properties including flexural and internal bonding properties were tested. The results showed that with increasing water uptake, the mechanical properties of the composites increased at first after reaching the maximum at water uptake of 30 wt% in accordance with the saturation point of cotton stalk. Therefore, the water contributed to the good interface between mycelium and cotton stalk particles, where the flexural and internal bonding strength met the standard for non-load bearing particleboard listed in ANSI A208.1–2016. However, at water uptake higher than 30 wt%, no further improvement occurred due to the excessive water located in cell lumen rather than in the cell wall.