Waste‐derived low‐cost mycelium composite construction materials with improved fire safety

Abstract

Summary Mycelial growth attracts academic and commercial interest because of its ability to upcycle agricultural and industrial wastes into economical and environmentally sustainable composite materials using a natural, low‐energy manufacturing process able to sequester carbon. This study aims to characterise the effect of varying ratios of high silica agricultural and industrial wastes on the flammability of mycelium composites, relative to typical synthetic construction materials. The results reveal that mycelium composites are safer than the traditional construction materials considered, producing much lower average and peak heat release rates and longer time to flashover. They also release significantly less smoke and CO2, although CO production fluctuated. Rice hulls yielded significant char and silica ash which improved fire performance, but composites containing glass fines exhibited the best fire performance because of their significantly higher silica concentrations and low combustible material content. Higher concentrations of glass fines increased volume‐specific cost but reduced mass‐specific and density‐specific costs. The findings of this study show that mycelium composites are a very economical alternative to highly flammable petroleum‐derived and natural gas‐derived synthetic polymers and engineered woods for applications including insulation, furniture, and panelling.

Physico-Mechanical and Thermodynamic Properties of Mycelium-Based Biocomposites: A Review

“…The heat release rate (HRR) is regarded as particularly important in modelling the growth and spread of fires, whereas TGA can provide additional information on the volatilization of combustion or pyrolysis compounds. While imposing the same incident thermal heat flux (50 kW m −2 ), Holt et al (2012) [40] and Jones et al (2018) [44] reported similar values, both for average HRR (55-75 and 33-107 kW m −2 respectively) and peak HRR (66-116 and 79-185 kW m −2 , respectively). This means that the peak occurs within the first minute after ignition.…”

“…Only a few studies deal with the behavior of the final mycelium-based composites toward fire, combustion and/or pyrolysis. According to Jones et al (2018) [44], MBFs show time that is similar to ignition in comparison to extruded polystyrene (XPS) foam, but significantly shorter than particleboard. Ignition temperature has been reported to range between 200 • C and 400 • C but, interestingly, mycelium does not show intrinsic flame-retardant properties and only acts as a cement instead [22,49].…”

“…Ignition temperature has been reported to range between 200 • C and 400 • C but, interestingly, mycelium does not show intrinsic flame-retardant properties and only acts as a cement instead [22,49]. According to Jones et al (2018) [44], this is due to the passivation of the MBF occurring when its superficial layers turn to char (primarily amorphous carbon). Char is, in fact, known to delay smoke production and spread, as well as decreasing thermal conductivity [55].…”

Fungal evolution: diversity, taxonomy and phylogeny of the Fungi

“…The metabolic singularities of many fungi have provided humanity with fermented foods and beverages to feed us and delight our senses, medicines to cure our bodies, and many compounds with important industrial usages. Fungi themselves are an important and valued source of food, and in the near future fungal biomass might even help to clothe and shelter us (Wojciechowska, ; Jones et al ., ).…”

Modified recipe to inhibit GSK-3 for the living fungal biomaterial manufacture

“…Mycelium-based biomaterials have a wide range of applications due to their controlled and tunable properties during growth, its self-assembly, self-healing, environmentally responsive, and biodegradable nature. The dried mycelium has strength, durability, and many other beneficial qualities: it is nontoxic, fire-resistant, mold resistant, water-resistant, and a great thermal insulator, amongst other salient features(1–13). Under proper circumstances, mycelium of many mushroom-forming fungi will aggregate to form mushrooms, which are the fruiting body spreading spores(14).…”