# Mycelium-Based Thermal Insulation for Domestic Cooling Footprint Reduction: A Review
## 4 Mechanical, Physical, and Chemical Characterization of Mycelium-Based Composites
Subsequently, they compared these values with conventional insulation materials, such as EPS. The study revealed that mycelium bricks exhibit favorable thermal properties, offering a significant environmental benefit. The measured thermal conductivities of the tested samples ranged from 0.078 to 0.081 W/m\(\cdot\)K, while the heat capacities ranged between 0.369 and 0.501 MJ/m\({}^{3}\)K [19]. A group of researchers developed a green building material by preparing a lightweight mycelium brick. Mycelium was cultivated within the substrate and subsequently compressed within a mold to shape a brick structure. After being burnt, the resulting mycelium brick was tested for compressive strength and water absorption. The researchers found that this material could be used in constructing non-load-bearing walls, pending further research to achieve the required strength. The result obtained from the compression test is 0.347 N/mm\({}^{2}\), the water absorption test is 33.81%, density is 250 Kg/m\({}^{3}\)[30]. Another study investigated how increased proportions of high-silica waste influence the fire safety of mycelium composites. The authors thoroughly assessed their susceptibility to ignition compared to conventional synthetic construction materials like polystyrene and medium-density particleboard. The findings indicate that mycelium composites demonstrate superior fire performance characteristics such as reduced heat release rates, extended time to reach flashover, and reduced smoke and CO\({}_{2}\) emissions compared to synthetic materials. Additionally, including glass fines in the mycelium composites enhanced their fire safety properties by increasing their silica content and reducing their combustible material content [31]. Additional research explores the influence of various factors on the compressive strength of mycelium-based bio-composites. The study examines specimens cultivated using the Gray Oyster mushroom strain (_Pleurotus ostreatus_) on three distinct substrates: sawdust, straw, and a combination of sawdust and straw, both with and without supplementation. The research reveals that both the type of substrate and the presence of supplementation and their combined effects exert noteworthy impacts on compressive strength. Notably, the compressive strength values ranged from 0.02 MPa to 0.14 MPa, significantly lower than those of traditional materials. Additionally, the paper highlights that straw-based and mixed-substrate samples exhibited more significant strain at failure than sawdust-based samples, indicating a more elastic behavior [32]. Another research examines how the growth medium composition can impact the properties of fungal mycelium. The authors conducted experiments using _Ganoderma lucidum_ mycelium, grown in various variants of potato dextrose broth (PDB). The results revealed that modifying PDB with d-glucose or lignin influenced the mycelium's morphology, hydrodynamics, and mechanical properties. Mycelium cultivated in PDB enriched with d-glucose displayed increased thickness, greater porosity, and higher hydrophilicity. Conversely, mycelium grown in PDB rich in lignin exhibited denser growth, faster development, and hydrophobic characteristics. Despite the differences, all mycelium samples had high water contact angles and resisted high temperatures. The authors conclude that mycelium-based materials offer a unique set of tunable properties that can be tailored to suit various applications [33]. An additional research effort examines the efficacy of mycelium-based composites (MBC) as an eco-friendly and biodegradable substitute for traditional insulation materials. The researchers utilize different substrates to cultivate MBCs and assess their physical attributes, including density, water absorption, thermal conductivity, and mechanical strength. Additionally, they analyze the hygothermal performance of MBCs through accelerated aging experiments and tests measuring moisture buffer capacity.