Effects of Mycelium-based Thermal Insulation Board Uniformity on Insulation Performance and Overall Physical Properties: Pathways for Future Quality Enhancements

Abstract

The impact of internal uniformity was studied relative to the insulation performance and properties of mycelium-based insulation boards (MBI) made from Lentinus sajor-caju and corn husk. The study examined how variations of mass per unit area and board thickness affected density, thermal conductivity, thermal resistance, and heat capacity. Density gradients were observed in the boards, ranging from 157 to 181 kg/m³, highest at the centerline and lowest at the edges. Thermal conductivity increased with density (0.049 to 0.063 W·m⁻¹·K⁻¹), while thermal resistance increased from center to edge, peaking at 0.471 m²·K·W⁻¹ at the 24 mm edge. Heat capacity was stable across samples (0.132 to 0.143 kJ/kg·K), indicating consistent thermal energy retention. Microscopic analysis confirmed these trends, showing structural compaction at the center and greater porosity at the edges, correlating with insulation performance. Pearson correlation analysis confirmed strong relationships between density, position, and thermal properties, notably a significant negative correlation between density and distance from the edge (r = -0.858, p = 0.003 at 16 mm thickness) and a strong positive correlation between thickness and thermal resistance (r = 0.999, p < 0.001). These findings support MBI boards as eco-friendly, high-potential alternatives to traditional insulation materials, allowing for further performance enhancement through optimized growth and mold design.