Abstract
Mycelium composites (MBCs) are emerging bio-composites that typically use mycelium to bind residues from agricultural or forest biomass. Despite their potential, there is limited research on mycelium-textile composites derived from textile waste, which currently accounts for approximately 5% of landfill volume. Additionally, there are not many studies on the production of mycelium composites using other lignocellulosic substrates, such as paper waste, of which nearly 25% are incinerated annually. These gaps highlight an opportunity to explore sustainable applications of mycelium in upcycling textile waste, contributing to waste reduction and advancing circular economy initiatives. This study aims to investigate the feasibility of producing mycelium composites using four types of substrates (i.e., muslin cotton, denim fiber, printing paper and kraft paper). Each of the substrates was mixed with actively growing mycelium from Ecovative testing kit at a mass ratio of 8:2. The samples were incubated in an environmental chamber at 25°C and relative humidity of 75% for 3 weeks. The composites were sterilized in an oven at 105°C and their physical properties (composite density, water absorption and thickness swelling), thermal properties (fire resistance, thermal conductivity and thermogravimetry), and compressive strength were assessed. FTIR spectroscopy was employed to observe the chemical changes that occurred in the substrate before and after composite formation. Results from the study showed that under compressive loads, the mycelium composites are approximately 650% and up to 3000% stronger than commercial expanded polystyrene and hemp insulation respectively. Additionally, Mycelium-paper (MP) and Mycelium-textile (MT) composites limit water absorption by up to 65% and 73% respectively compared to commercial hemp insulation (after 24 hours immersion) and maintain a compact structure even after longer periods of water immersion (7 days). Mass Loss Cone Calorimetry showed mycelium composites had lower peak heat release rates compared to their specific controls and although MT and MP composites show higher mass residues after test, and needed longer time to ignite, their total heat release rates were significantly higher than hemp insulation (p>0.05). The thermal conductivity of MT (0.051 – 0.055 W/m.K) and MP (0.054 - 0.059 W/m.K) places them among moderate insulators, and their thermal conductivities compare favorably to conventional insulation materials such as hempcrete, straw insulation and polyester insulation. These findings show the capabilities of mycelium to bind textile and paper wastes for the production of eco-friendly insulation alternatives.