Effect of cold and hot pressing in mycelium-based foams fabrication: Unraveling morphological, mechanical, and thermal properties

Mycelium-based foam is a sustainable alternative to synthetic polymers, produced biologically using the vegetative part of fungi, known as mycelium. This study examines the impact of fabrication conditions on the morphology and mechanical, water-related, and thermal properties of mycelium-based foams. Pleurotus citrinopileatus and Pleurotus djamor were cultivated on ground paddy straw at 25°C for 21 days under dark conditions. The samples were subjected to hot pressing at 150°C, cold pressing at 25°C, or left unpressed as a control. Scanning electron microscopy (SEM) analysis revealed that cold-pressed P. citrinopileatus foam (YCP) exhibited the most compact hyphal structure, contributing to superior mechanical properties, with the highest tensile strength (4.324 ± 0.857 MPa), elongation at break (0.260 ± 0.040), and modulus (16.459 ± 2.552 MPa). Additionally, YCP showed the lowest water absorption (0.126 ± 0.190), indicating enhanced resistance to moisture. Thermogravimetric analysis showed that YCP retained structural integrity up to 600°C, with major mass loss occurring above this temperature, indicating high thermal stability suitable for demanding applications. These findings highlight the potential of mycelium-based foam as a biodegradable, high-performance material for packaging and insulation applications.