Mycelium Composites Research Articles

Fabrication factors influencing mechanical, moisture- and water-related properties of mycelium-based composites

Mycelium-based composites result from the growth of filamentous fungi on organic materials such as agricultural waste streams. These novel biomaterials represent a promising alternative for product design and manufacturing both in terms of sustainable manufacturing processes and circular lifespan. This study shows that their morphology, density, tensile and flexural strength, as well as their moisture- and water-uptake properties can be tuned by varying type of substrate (straw, sawdust, cotton), fungal species (Pleurotus ostreatus vs. Trametes multicolor) and processing technique (no pressing or cold or heat pressing). The fungal species impacts colonization level and the thickness of the air-exposed mycelium called fungal skin. Colonization level and skin thickness as well as the type of substrate determine the stiffness and water resistance of the materials. Moreover, it is shown that heat pressing improves homogeneity, strength and stiffness of the materials shifting their performance from foam-like to cork- and wood-like. Together, these results demonstrate that by changing the fabrication process, differences in performance of mycelium materials can be achieved. This highlights the possibility to produce a range of mycelium-based composites. In fact, it is the first time mycelium composites have been described with natural material properties.

Mechanical behavior of mycelium-based particulate composites

This work investigates the mechanical behavior of mycelium composites reinforced with biodegradable agro-waste particles. In the composite, the mycelium acts as a supportive matrix which binds reinforcing particles within its filamentous network structure. The compressive behavior of mycelium composites is investigated using an integrated experimental and computational approach. The experimental results indicate that the composite mimics the soft elastic response of pure mycelium at small strains and demonstrates marked stiffening at larger strains due to the densification of stiff particles. The composite also exhibits the characteristic stress softening effect and hysteresis under cyclic compression previously observed for pure mycelium. To gain further insight into the composite behavior, a three-dimensional finite element model based on numerical homogenization technique is presented. Model validation is performed by direct comparison with experiments, and a parametric study of the effect of mycelium density and particle size is discussed.

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

SummaryMycelial 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.

Mycelium Composites: A Review of Engineering Characteristics and Growth Kinetics

Mycelium composites comprise of networks of filamentous hyphae, utilising biological growth rather than expensive energy intensive manufacturing processes to convert low-cost organic wastes into economically viable and environmentally friendly materials. Although generally characterised as polymer grade foams and used primarily for limited packaging and construction applications, the mechanical performance of these materials varies significantly and is governed by hyphal architecture, cell wall composition, composite constituents and growth kinetics which are in turn influenced by inherent and exogenous factors. A range of potential applications have been proposed including acoustic dampers, super absorbents, paper, textiles, structural and electronic parts. Limited research, inconclusive data and the proposed applications and feasibility suggest that further investigation is warranted.