# Mycelium-Based Thermal Insulation for Domestic Cooling Footprint Reduction: A Review
## 4 Mechanical, Physical, and Chemical Characterization of Mycelium-Based Composites  
Recent advancements in developing mycelium-derived bio-composite materials have generated significant interest in design and architecture due to their potential as sustainable and biodegradable alternatives to conventional insulation materials. Mycelium-based insulation has emerged as a promising solution that offers unique mechanical, physical, and chemical characterization (Table 1). Previous studies have focused on assessing these composites' strength, stiffness, toughness, and fatigue resistance through various testing methods, including tensile, compressive, flexural, and impact tests. These investigations have shed light on the composite's load-bearing capacity, deformation behavior, and resistance to mechanical stresses. Furthermore, the influence of various factors, such as mycelium species, growth conditions, and composite formulation, on mechanical performance has been explored to optimize the material design and enhance mechanical properties. Mycelium-based materials exhibit low  
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density, sound insulation, and nonlinear behavior under tension and compression. The density of materials derived from mycelium falls within the range of 0.02 to 0.2 g/cm\({}^{3}\), comparable to or lower than that of EPS (0.01-0.2 g/cm\({}^{3}\)). The properties of mycelium-derived materials are related to their porosity and microstructure, which affect their thermal conductivity and sound absorption coefficients. The thermal conductivity of mycelium-based materials varies from 0.03 to 0.07 W/m\(\cdot\)K, which is similar to or lower than that of EPS (0.03-0.04 W/m\(\cdot\)K). At the same time, the sound absorption coefficients of mycelium-derived materials fall within the range of 0.4 to 0.9 at frequencies between 500 and 2000 Hz, which are higher than those of EPS (0.2-0.4) [27]. A study investigated the mechanical properties of mycelium composites produced using _Trantes versicolor_, a white-rot fungus. Incorporating bacterial cellulose, a natural additive, further enhanced these composites. The inclusion of bacterial cellulose led to enhancements in both the internal bond strength and the mechanical adjustability of the mycelium composite materials. This review presents findings indicating that the dry density of the composite material varies within the range of 460.30 to 531.17 kg/m\({}^{3}\), with fluctuations corresponding to the bacterial cellulose content. Additionally, the findings demonstrate that the particle boards exhibit flexural strength and modulus values spanning from 1.46 to 2.94 MPa and 0.22 to 0.44 GPa, respectively [28]. A comprehensive study delves into utilizing mycelium-based bio-composite materials within the domains of design and architecture. The primary objective is to identify the optimal combination of fungal species and agricultural waste materials, yielding biodegradable, renewable, and innovative properties. The investigation encompasses four distinct fungi species--_Pleurotus pulomarius, Pleurotus ostreatus, Pleurotus salmonestramineus_, and _Aaegerita agroche_--alongside five types of plant waste--eucalyptus, oak, pine, apple, and vine woodchips. Multiple attributes are assessed, including pH, electrical conductivity, water content, carbon and nitrogen levels, mycelium growth rate, density, and quality assessment. The study's findings underscore that the most efficacious synergies emerged from _Pleurotus ostreatus_ samples cultivated on apple or vine woodchips [29]. A recent investigation has explored the feasibility of employing mycelium bricks as a practical insulation solution for architectural structures. The study emphasized harnessing a specific type of basidiomycte fungi to cultivate mycelium bricks utilizing straw waste as the substrate. The researchers conducted an assessment to ascertain the thermal conductivity and specific heat capacity of these mycelium bricks.