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![Effect of particle size on mechanical properties of mycelium composites: a stress–stretch curves, and b the dependence of the loading modulus (Ec\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ E_{\text{c}} $$\end{document}) and c unloading modulus (Ecu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ E_{\text{c}}^{\text{u}} $$\end{document}) on filler size. The error bars represent the range of four test samples](publication/327065922/figure/fig4/AS:779414744875013@1562838364605/Effect-of-particle-size-on-mechanical-properties-of-mycelium-composites-a-stress-stretch.png)
Effect of particle size on mechanical properties of mycelium composites: a stress–stretch curves, and b the dependence of the loading modulus (Ec\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ E_{\text{c}} $$\end{document}) and c unloading modulus (Ecu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ E_{\text{c}}^{\text{u}} $$\end{document}) on filler size. The error bars represent the range of four test samples
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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 experimen...
Citations
... However, lignin found in coir-pith prevents microorganisms from decomposing it as easily as sawdust, giving it a far longer shelf life than sawdust [7], [12]. The trial-and-error method is used to determine the 3:2 ratio [19]- [21]. The physical and chemical properties of raw materials used to develop the biocomposite samples are shown in Table 1. ...
Mycelium biocomposite materials have been established as a sustainable alternative to polystyrene in single use applications like packaging. However only little investigations are done on improving their resistance to fire and heat, which can find use in newer applications. This paper focuses on the development and characterization of a mycelium-based sawdust-coir pith biocomposite material treated with a combination of fire-retardant compounds (borax and boric acid). The outcomes of fire resistance tests, such as flammability, flame penetration and rate of burning demonstrated a significant improvement in values with respect to untreated samples. However, samples having 30% boron compounds by weight in it exhibited the best fire resistance properties. The thermal analysis of treated samples indicated that the presence of fire-retardant chemicals has not significantly affected their thermal stability. The glass transition temperature (Tg) of treated mycelium composite material was found to be 212.75 °C against a value of 207.78 °C for untreated samples. The fire retardant treated mycelium composite samples having 30% boron by weight in it, exhibited an average sound absorption coefficient of 0.38 compared with a sound absorption coefficient of 0.29 for polyurethane foam. The prepared mycelium biocomposite has a self-extinguishing nature and exceptional fire resistance capabilities with an LOI value of 50%. The mechanical testing revealed that the presence of fire-retardant chemicals has significantly improved the flexural properties. However, only a marginal increase was visible in the compression strength of mycelium biocomposites.
... Thus, for future studies, it will be useful to know that while 0.4 wt% ME is too low to optimize growth speed, adding ME concentrations > 2 wt% will not necessarily lead to faster mycelium proliferation. Furthermore, considering material applications, it is worth noting that dense mycelial growth can contribute to stronger and more cohesive structures 37 . Absorbance measurements indicate that G. sessile and G. lucidum exhibit comparable mycelium network connectivity. ...
... Most of mycelium density data of Basidiomycota in the literature is obtained via the ratio of biomass per unit of area/mass 22,[37][38][39] and absorbance in the context of fungi to measure biomass accumulation 36 . Herein, we show that absorbance (optical density, OD) at 595 nm wavelength can be used to assess mycelium network density. ...
With its distinctive material properties, fungal mycelium has emerged as an innovative material with a diverse array of applications across various industries. This study focuses on how the growth strategies of wood fungi adapt to nutrient availability. The effect of malt extract concentration in the growth medium on radial growth kinetics, morphology, mycelium network connectivity, and mechanical characteristics of mycelium from two Ganoderma species were investigated. While an evident pattern of radial growth rate enhancement with malt concentrations was not apparent, there was a discernible trend towards denser mycelium network characteristics as revealed by spectrophotometry. Increased malt extract contents corresponded to elevated optical density measurements and were visually confirmed by denser mycelium networks in photographic images. Investigating the mechanical characteristics of mycelium cultivated on varying solid substrate concentrations, the Young’s modulus exhibited a substantial difference between mycelium grown on 5 wt% malt substrate and samples cultivated on 2 wt% and 0.4 wt% malt substrates. The obtained results represent a new understanding of how malt availability influences mycelial growth of two Ganoderma species, a crucial insight for potentially refining mycelium cultivation across diverse applications, including meat alternatives, smart building materials, and alternative leather.
... This improvement in the mechanical properties of the composite sample is influenced not only by the heat and pressure during hot pressing but also by the presence of mycelium on the composite surface. The mycelium reinforces and holds the fiber together, forming a strong fiber network to maintain its durability during testing [75]. However, one limitation observed in this study is that the amount of mycelium inoculated in MBC is not sufficient and not well distributed into the internal part of the composite. ...
Rubber wood sawdust (RBS) represents a prominent agricultural waste, notable for its high lignocellulose content. This unique composition not only renders it eco-friendly but also offers enhanced mechanical strength, biodegradability, and cost-effectiveness, making it a promising candidate for composite materials. Beyond its traditional role in the mushroom industry, the potential of RBS is increasingly recognized in the realm of sustainable composites, especially in mycelium composite technology. This study delves into creating a biodegradable composite that effectively harnesses this waste. This study assessed critical inoculation conditions, such as moisture content (50 to 80%), pressing temperatures, and oxygen availability, for their influence on the properties of mycelium-based composites (MBC). Thermogravimetric analysis pinpointed mycelium degradation at 270 °C, tied to chitin disintegration, with RBS fiber initiating weight loss at 250 °C. Notably, MBC panels pressed at 130 °C surpassed mycelium-free controls (CRM) in flexural strength, stability, and morphology. SEM investigations further emphasized the mycelium as self-binding matrix microorganism in the composite, enhancing void filling and bonding. These findings highlight the suitability of RBS as a waste-derived material in mycelium composites, paving the way for innovative, eco-conscious applications.
Graphical Abstract
... In both methods, fungi require direct contact with their nutrient source. In solid-state fermentation, the growth can be performed on a solid substrate [3,10]. The hyphae can interlock the substrate within its network and outward growth away from the substrate into the air. ...
Mycelium materials are an emerging class of natural, inexpensive, and environmentally sustainable materials. They are promising alternatives to petroleum-based polymeric ones, and they can also be used as substitutes for animal-based leather. This work investigates the water relation properties (equilibrium and transfer) of pure mycelium materials produced using Ganoderma lucidum fungal species in liquid-state fermentation. The dynamic gravimetric method was used to determine sorption isotherms at four temperatures (20 °C, 30 °C, 40 °C, and 50 °C) over a water activity (a w) range of 0 to 0.9. This material is highly hygroscopic and depicts a huge condensation phase at high water activity, with an equilibrium moisture content of 53% at 20 °C and 90% RH. Among the eight sorption models tested, the GAB model gives good results and was further used to analyze data. Thermodynamic properties (net isosteric heat of sorption, sorption entropy change, and the isokinetic temperature) were determined from the sorption isotherms to represent better the energy related to the sorption processes. Finally, the transient stages of sorption measurement were analyzed to extract mass transfer properties. Consistently with the morphology of this material, a dual-scale effect is evidenced, which turns into a representation by two independent parameters: the macroscopic and microscopic mass diffusivity values.
... Further, the plastic modulus of the mixture depends on the weight ratio of the ceramic microparticles and the polymer, as well as the distribution and densification of the particles within the matrix. As observed experimentally, a higher volume fraction and densification of the ceramic particles can lead to a higher plastic modulus Field (Islam et al., 2018). Overall, our results demonstrated that the initial elastic compressive moduli and the toughness of the scaffolds decrease with reduced PCL% despite the increased HA:PCL ratio in printable inks. ...
Introduction: Low-temperature extrusion three-dimensional printing (LTE-3DP) using viscous ceramic-polymer inks has shown promise for bone tissue engineering. This process involves formulating a flowable ink by combining ceramic powders and other components with organic or inorganic polymer solutions, which can then be extruded through a 3D printer nozzle. LTE-3DP allows the incorporation of high fractions of bioactive ceramics and thermally labile additives such as drugs, proteins, and biomolecules into the inks to promote osteogenesis and bone regeneration. The rheology of the ink, influenced by various variables, significantly impacts the printability and form fidelity of the resulting scaffolds. These variables include the composition of the polymer solution and the size and weight ratio of ceramic microparticles. In this study, we posited that the printability of hydroxyapatite (HA) and polycaprolactone (PCL) mixture inks could be optimized by tailoring their rheological properties.
Methods: We conducted a systematic investigation, varying the PCL weight percentage and HA:PCL weight ratio, to examine the effects of the ink’s composition on its viscosity and storage modulus, as well as its printability and the mechanical properties of 3D printed HA:PCL scaffolds.
Results: We demonstrated that HA:PCL inks exhibit predictable non-Newtonian fluid behavior at higher fractions of HA, displaying significant shear thinning at elevated shear rates, which can facilitate extrusion through a 3D printing nozzle. We identified printable ink compositions based on filament continuity and scaffold form fidelity criteria. Moreover, we performed computational simulations to analyze the ink flow through an extrusion nozzle. These simulations utilized the Herschel-Bulkley-Papanastasiou constitutive model, considering the rheological properties obtained from experimental measurements. By combining experimental measurements and computational simulations, we formulated a non-dimensional Printability number that predicts whether an ink is printable based on the ink’s rheological parameters and printer-specific factors. Furthermore, we evaluated the compressive properties of printed HA:PCL scaffolds and characterized the effects of PCL% and HA:PCL ratio on the hyperelasticity observed in response to compressive deformations.
Discussion: This hybrid approach using experimental rheology and FE simulations provides a framework to define the printability of ceramic-polymer ink formulations, which could help streamline the 3D printing of novel inks for bone tissue engineering.
... To address these issues, researchers are exploring different routes such as mycelium composites [26][27][28], foam [29,30] and leather [31,32]. We are exploring the use of agricultural waste as a source of raw material for foam production. ...
... The powder obtained has similar characteristics to that obtained by the wet milling reported previously [35]. The non-fibrous component of pineapple leaf waste was obtained by grinding fresh pineapple leaves according to the method previously described in [29,30]. The ground material was dried and then sieved with plastic wire mesh of approximately 2 mm 2 to separate out the puffy fibrous component. ...
Pineapple materials sourced from agricultural waste have been employed to process novel bio-degradable rigid composite foams. The matrix for the foam consisted of starch extracted from pineapple stem, known for its high amylose content, while the filler comprised non-fibrous cellulosic materials sourced from pineapple leaf. In contrast to traditional methods that involve preparing a batter, this study adopted a unique approach where the starch gel containing glycerol were first formed using a household microwave oven, followed by blending the filler into the gel using a two-roll mill. The resulting mixture was then foamed at 160 °C using a compression molding machine. The foams displayed densities ranging from 0.43–0.51 g/cm3 and exhibited a highly amorphous structure. Notably, the foams demonstrated an equilibrium moisture content of approximately 8–10% and the ability to absorb 150–200% of their own weight without disintegration. Flexural strengths ranged from 1.5–4.5 MPa, varying with the filler and glycerol contents. Biodegradability tests using a soil burial method revealed complete disintegration of the foam into particles measuring 1 mm or smaller within 15 days. Moreover, to showcase practical applications, an environmentally friendly single-use foam tray was fabricated. This novel method, involving gel formation followed by filler blending, sets it apart from previous works. The findings highlight the potential of pineapple waste materials for producing sustainable bio-degradable foams with desirable properties and contribute to the field of sustainable materials.
... Moreover, the main precursors of Styrofoam are benzene and styrene, which have been classified as carcinogens, and these residues can present health risks for producers and consumers of Styrofoam (Chandra et al., 2016), (Farrelly & Shaw, 2017). Biofoam or bio-degradable foam is a material produced by natural sources, such as starch (Sumardiono et al., 2021), cellulose (Adiyar et al., 2019), protein (Wu, 2017), and mycelium-based (Bruscato et al., 2019), (Islam et al., 2018), to substitute the use of Styrofoam. During the last few years, research and development of mycelia-based biofoam have been carried out widely due to the simple process and molded easily. ...
Biofoam, a biodegradable foam, was developed with the purpose of replacing the use of Styrofoam, particularly as food containers. Fungal mycelia as well as polysaccharides and proteins can be used to create foam. The type of fungi, substrate composition, and incubation condition all have an impact on the fabrication of mycelia-based biofoam. Hence, in this research, the fabrication, and properties evaluation of Rhizopus oligosporus mycelia-based biofoam were carried out using various lignocellulosic (sugarcane trash (SCT), pineapple leaves (PL), and a mix of both with the inoculum concentration (20%, 25%, and 30%)). The substrate also included soybean starch, CaCO3, and water (in a ratio of 5:2:15 %w/w of the lignocellulosic used). The results showed that the inoculum required for optimum mycelium growth on the SCT, PL, and mix substrates was 25%, 25%, and 30%, respectively. Biofoams (S2, P2, and SP3) have low moisture content and water absorption but high density and biodegradability compared with other biofoams. The biofoams obtained from this study also had a higher MOE and lower MOR than Styrofoam as the control.
... In recent years, the multifunctionality issue and the control of the effects obtained with the self-growing process appear to be more and more developing. Some examples can be reported, such as the possible modelling of the effect of particulate agrowaste on the mechanical properties of mycelium-based composites (Islam et al., 2018). Moreover, as regards multifunctional approach, the coupling of other effects e.g., creating composites able to absorb heavy metal ions, such as Cu (II), contributing therefore to bioremediation, has been investigated, with particular attention to spontaneous plants (Aspergillus campestris) (Saravanan et al., 2020). ...
Mycelium-grown composites, also referred to as “myco-composites”, have raised a large attention in recent years, for their ongoing transformation into technical materials, in search of an adequate positioning and role in the field of architecture and design.
... Therefore, compressive strength is the most often tested mechanical property. In this system, the mycelia are believed to behave as a supportive matrix (Figure 16.3a), and the substrates act as reinforcing components in the mycelia network [45]. Thus, the mycelia matrix defines the elastic response under compression at initial small strains, while the stiffening at large strains is caused by the densification of the hard substrate materials [45]. ...
... In this system, the mycelia are believed to behave as a supportive matrix (Figure 16.3a), and the substrates act as reinforcing components in the mycelia network [45]. Thus, the mycelia matrix defines the elastic response under compression at initial small strains, while the stiffening at large strains is caused by the densification of the hard substrate materials [45]. ...
... Elsacker et al. found that the samples with a smaller fiber size resulted in a higher compressive modulus [41]. In contrast, Islam et al. found that the compressive properties of mycelium-bonded bio-composites are particle size-independent [45]. Elsacker et al. also claimed that denser mycelia colonization resulted in a higher compressive modulus [41], whereas Sun found that the different densities of the mycelia matrices in the bio-composite did not significantly affect either the compressive modulus or strength [31]. ...
... Several studies have focused on engineering renewable materials from a variety of naturally available resources such as bamboo (Sun et al., 2022), (Onche et al., 2021), eggshell membrane (Baláž, 2014), cotton plant biomass (Holt et al., 2012), and silk protein (Vepari and Kaplan, 2007). Many natural materials also provide a unique advantage due to the combination of interesting properties that often result from their filamentous and hierarchical architectures (Islam et al., 2018;Meyers et al., 2008;Wegst et al., 2014). Some of these unique properties have been used in bioinspired and sustainable engineering designs. ...
... Some of these unique properties have been used in bioinspired and sustainable engineering designs. However, although the chemical compositions of the materials and structures in these designs are well established, there is still only a limited understanding of the structure-property relationships and the interplay and mechanistic intricacies required for robust material design and process optimization (Islam et al., 2018). ...
... It consists of hyphae, which are microscopic tubular filaments of varying geometries depending on the strain. The diameter of a typical hypha is in the range of 1-30 μm (Islam et al., 2018), (Geitmann and Emons, 2000) ( Fig. 1d and e). The fungus starts as a spore and develops into a hypha that grows out through apical tip elongation (Islam et al., 2018). ...
This study investigates the compressive deformation and the effect of structural architecture on the compressive strength of bioprocessed mycelium biocomposites reinforced with laterite particles. In the mycelium blocks, lignocellulosic hemp hurds function as reinforcing and nutritional substrates. The mycelium acts as a supportive matrix, binding the hemp hurds and the laterite particles which are integrated for further reinforcement to improve the compressive strength of the composite. The compressive behavior of the composites is elucidated using a combined approach of experimental and theoretical studies. The deformation mechanisms are investigated via in-situ observations of the specimens under uniaxial compressive loading. The experiments show that the compressive deformation results in progressive micro-buckling in slender specimens, whereas thicker samples exhibit a soft elastic response at small strain levels followed by continuous stiffening at larger strains. Based on the experimental observations and the morphological characterization, a column buckling analysis was developed for the mycelium-hemp composites to further explain the observed deformation phenomena.
