Abstract:To solve the environmental pollution and harm to human health caused by the use of adhesives in traditional paperboard, the development of environmentally friendly mycelium paperboard has become a hot topic. Due to the high dipole moment and hydrogen bonding between macromolecules, hyphae can form clamp shaped connection structures for nutrient reproduction and transfer, and can grow on natural agricultural waste, forming a natural biocomposite material. This study determined the combination of Ganoderma weberianum/corn straw, and designed single factor cultivation conditions such as cultivation time, straw particle size, and fructose addition to explore the effects on the mechanical properties, waterproof properties, and thermal decomposition performance of the hyphal paperboard formed by hot pressing. The optimal cultivation process was obtained through orthogonal experiments. The experimental results indicate that various factors have varying degrees of influence on the edgewise strength, flexural stiffness, and static bending strength and waterproofness of paperboard. Firstly, when the cultivation time was 30 days, the flexural stiffness reached 16.63 mN/m, which was 21.2% higher than the flexural stiffness of kraft paper (13.10 mN/m). Moreover, with the increase of cultivation time, the water absorption (24 hours) had also decreased from 3.92% to 1.27%. Secondly, previous research results have shown that the addition of fructose, glucose, and sucrose increases the biomass growth rate of strains. In this study, fructose was chosen as an exogenous nutrient, and the results showed that when a mass fraction of 5% fructose was added, the mechanical properties were the best, with a flexural stiffness of 18.87 mN/m, which was 30.5% higher than that of kraft paper (13.10 mN/m). Thirdly, the particle size of the sbstrate has a significant impact on the appearance and properties of the material. The results show that, from the appearance perspective, the mycelium paperboard made of 0.165~0.250 mm particle size has the closest appearance and feel to kraft paper. At the same time, during the testing period, it was found that the mycelium paperboard made of 0.165~0.250 mm straw was the least prone to deformation and loosening, and the molding effect was significantly improved compared to other components. In terms of mechanical properties, the edgewise strength increased by 17.4%, the static bending strength increased by 14.9%, and the flexural stiffness increased by 57.3%. The experimental results show that the degree of influence of various factors on the edgewise strength, flexural stiffness, and static bending strength of paperboard is in the order of particle size, cultivation time,fructose addition amount. When the particle size is 0.165~0.250 mm, the cultivation time is 30 days, and the fructose addition of 5.0%, the edgewise strength of the prepared paperboard is 14.36 N/mm, the static bending strength is 10.89 MPa, and the flexural stiffness is 33.09 mN/m. As the particle size decreases, the water absorption rate and water thickness expansion rate of the paperboard after 24 hours of water absorption decrease to 0.86% and 0.59%. The mycelium paperboard prepared by different single factors has the same thermal decomposition process, starting at around 150 ℃ and reaching its maximum at 350 ℃. This study provides a reference basis for the development and application of mycelium composite materials in the future.