The Effects of the Substrate Length and Cultivation Time on the Physical and Mechanical Properties of Mycelium-Based Cushioning Materials from Salix psammophila and Peanut Straw

Abstract

Mycelium-based biocomposites represent a novel class of environmentally friendly materials. This study investigated the potential of using Salix psammophila and peanut straw as substrates for cultivating Pleurotus ostreatus and Ganoderma lucidum, respectively, to fabricate mycelium-based cushioning materials. The results demonstrated that the Pleurotus ostreatus-based cushion material using Salix psammophila (POSM) outperformed the Ganoderma lucidum-based cushion material using peanut straw (GLPM) in terms of overall performance. Both materials presented optimal comprehensive properties when the cultivation period reached 30 days. Increasing the substrate length enhanced most of the material properties. The resulting density ranged from 0.13 to 0.16 g/cm³, which was higher than that of polystyrene foam. The contact angles of both materials exceeded 120°, whereas their elastic springback rates reached 50.2% and 43.2%, and their thermal conductivities were 0.049 W/m·K and 0.051 W/m·K, respectively. Additionally, thermogravimetric analysis revealed that both materials exhibited similar thermal degradation behavior and relatively high thermal stability. These findings align with those of previous studies on mycelium composites and indicate that the physical and mechanical properties of the materials are largely comparable to those of expanded polystyrene (EPS). In conclusion, the developed mycelium-based cushioning materials promote the efficient utilization of agricultural residues and hold promise as a sustainable alternative to EPS, offering broad application prospects in the transportation and packaging sectors.

Keywords: cultivation time; lignocellulose; mycelium; mycelium-based cushioning materials; substrate length.

Figure 1

(a) Salix psammophila and peanut straw with different substrate lengths; (b) mycelial growth at different cultivation times.

Figure 2

Images of mycelium-based cushioning materials derived from different lignocellulosic substrates: (a,c) show the microscopic morphology of Pleurotus ostreatus and Ganoderma lucidum mycelia, respectively (3000×); (b,d) display the cross-sectional morphology and internal microstructure of POSM and GLPM, respectively (1000×); (e,f) present the surface morphology of POSM and GLPM, respectively (1×).

Figure 3

FTIR spectra of Salix psammophila, peanut straw, and mycelium-based cushioning materials.

Figure 4

TG and DTG curves of Salix psammophila, peanut straw, and mycelium-based cushioning materials.

Figure 5

Mycelium-based cushioning materials at various cultivation times and before and after compression: (a) morphological characterization at different cultivation times; (b) comparison of the materials before and after compression after 30 days of mycelial cultivation.

Figure 6

Stress–strain curves and elastic spring back rates of mycelium-based cushioning materials at different cultivation times: (a,c) for POSM; (b,d) for GLPM (p < 0.05).

Figure 7

Stress–strain curves and elastic spring back rates of mycelium-based cushioning materials with different substrate lengths: (a,c) for POSM, (b,d) for GLPM (p < 0.05).

Figure 8

Thermal conductivity and contact angle of mycelium-based cushioning materials with different cultivation times and substrate lengths: (a,c) for POSM, (b,d) for GLPM (p < 0.05).

Figure 9

Static water contact angles of the mycelium-based cushioning materials.