Polystyrene, a ubiquitous material found in packing peanuts and various cushioning applications, is synthesized from fossil fuels and presents significant environmental challenges due to its non-biodegradability and reliance on petrochemical resources. Seeking an eco-friendly substitute, the research team turned to sawdust, a byproduct of lumber production traditionally regarded as waste, to engineer bio-based foams with potential to revolutionize packaging and building materials industries. The process involved refining sawdust into fine and coarse particles, which were then blended with different cellulose-based binders to create foam prototypes exhibiting either rigidity or flexibility.

The sawdust used in the experiments was combined with cellulose binders such as carboxymethyl cellulose and hydroxypropyl cellulose. These polymers serve as primary agents to form the foam matrix, governing the mechanical stiffness and elasticity of the final products. Carboxymethyl cellulose yielded foams that outperformed polystyrene in stiffness, whereas hydroxypropyl cellulose produced softer, more flexible foams. By manipulating the cellulose binder types, the researchers demonstrated the ability to tailor the foam properties according to the intended application.

To fabricate these foams, the team adopted a sophisticated freeze-drying technique. The sawdust-cellulose mixtures were poured into molds and subjected to freezing, followed by freeze drying to eliminate moisture without collapsing the foam structure. This method preserved the porous, lightweight architecture essential for cushioning applications. A subsequent heat-drying stage activated citric acid cross-linkers, creating chemical bonds within the foam network to enhance structural integrity and durability.

Notably, the team experimented with both fine processed wood powder and unprocessed mill waste sawdust in their formulations. Surprisingly, the mechanical properties, including strength and impact resistance, remained consistent regardless of the sawdust processing level. This finding underscores the versatility and robustness of the foam compositions, potentially simplifying sourcing by accommodating a range of sawdust qualities.

Water resistance, a critical attribute for packaging materials, was addressed by applying a thin beeswax coating to certain foam samples. This natural wax layer effectively enhanced moisture repellency, maintaining performance in high humidity environments without adversely affecting the mechanical characteristics. Such biobased coatings align with the sustainable ethos of the project and further extend the functional range of the foams.

Chemical stability assessments revealed that the sawdust-cellulose foams resisted dissolution in solvents like acetone, a feat polystyrene cannot match. Additionally, during water absorption and release cycles, the foams maintained their structure, demonstrating resilience critical for real-world handling and storage. These stability features suggest that the new materials could reliably replace polystyrene in numerous applications where chemical exposure or moisture is a concern.

Mechanical testing involving impact resistance demonstrated compelling performance advantages. When subjected to the drop of a 10-pound weight, the sawdust-based foams absorbed and dispersed energy more effectively than polystyrene samples of equivalent thickness, with the weight bouncing 21% less distance. This improved energy dissipation points to superior protective qualities, marking the foams as viable candidates for high-performance packaging, particularly in electronics and fragile goods transport.

The environmental implications of this research are significant. By repurposing sawdust waste, the project not only diverts material from landfills but also reduces dependence on fossil fuel-derived polymers. The creation of biobased foams capable of matching or exceeding polystyrene’s performance characteristics represents an important step toward circular economy models within materials science.

Looking ahead, the research team acknowledges the need for long-term stability studies to fully validate the durability of the foams across extended periods and diverse environmental conditions. Current evaluations over weeks to months indicate promising liquid stability, critical for transportation and storage scenarios where packaging materials may encounter accidental spills or varying humidity.

Beyond packaging, potential applications for these foams may extend into construction materials, where lightweight, rigid, and insulating properties are highly prized. Given the tunable nature of the material’s stiffness and resilience, future research could explore custom formulations balancing mechanical strength and flexibility to meet specific industrial demands.

The innovation described stems not only from novel chemistry but also from a sustainable philosophy prioritizing waste reuse over chemical inventory expansion. Access to sawdust from local farms and sawmills was instrumental, reflecting a community-oriented approach that underscores the practical viability of scaling this technology.

This research was supported by funding from the U.S. Department of Energy, highlighting official commitment to advancing sustainable polymer technologies. Collaboration with industry suppliers such as Hadley Millworks facilitated access to sawdust waste crucial for experimental progress.

In conclusion, the development of sawdust-based foams introduces a versatile, environmentally friendly alternative to polystyrene. By combining abundant biomass resources with smart chemical engineering, this work paves the way for next-generation packaging and building materials that reduce ecological footprints while maintaining high-performance standards.

Subject of Research: Development of sustainable biobased foams from sawdust as alternatives to polystyrene.

Article Title: Sawdust-based foam could offer a sustainable alternative to polystyrene

News Publication Date: 20-May-2026

Web References:
http://dx.doi.org/10.1021/acsapm.6c00854

References:
Adapted from ACS Applied Polymer Materials 2026, DOI: 10.1021/acsapm.6c00854

Image Credits:
Adapted from ACS Applied Polymer Materials 2026, DOI: 10.1021/acsapm.6c00854

Keywords

Physical sciences, Chemistry, Polymers, Sustainable materials, Biobased foam, Sawdust, Packaging materials, Polystyrene alternatives, Cellulose binders, Cross-linking, Freeze drying, Beeswax coating

Central to this research is the fungus known as Trametes versicolor, commonly referred to as the “turkey tail.” Unlike the more conspicuous mushroom cap that we see above the ground, fungi like T. versicolor possess a vast underground network called mycelium, composed of fine, thread-like structures known as hyphae. These mycelial networks already possess inherent water-repelling properties. By harnessing these characteristics, the researchers aimed to cultivate a food-safe, sustainable coating that adheres to and protects various substrates effectively.

The approach involved blending mycelia from T. versicolor with cellulose nanofibrils (CNFs) — ultrafine fibers derived from wood pulp known for their strength and barrier properties. CNFs are increasingly utilized in material science due to their biodegradability and capacity to form dense networks impermeable to gases and liquids. The process began by immersing materials such as denim fabric, polyester felt, birch veneer, and paper in a nutrient solution containing the fungal spores and CNFs. Over several days, the fungal mycelium grew a sustained layer on these substrates.

What makes this fungal coating remarkable is its minimal thickness, comparable to a layer of paint, which forms after just a few days of fungal growth. The researchers observed that after a 3-4 day incubation period in controlled warm environments, the coating demonstrated significant hydrophobicity. When water droplets were placed on treated surfaces, they formed spheres, indicating the liquid was repelled rather than absorbed. This phenomenon contrasts starkly with untreated materials where water either spread out thinly or was immediately soaked in.

In addition to water resistance, the composite film exhibited barriers against a suite of other challenging liquids including n-heptane, toluene, and castor oil. This suggests that the fungal coatings can withstand a broad spectrum of chemical exposures, broadening their application potential beyond just food packaging. Importantly, once the film had developed, the samples underwent a heat treatment in an oven for one day. This process inactivated the fungus, ensuring the coating was stable and no longer biologically active, while also enabling the film to dry and solidify.

The aesthetic changes induced by the mycelium were notable: the coatings imparted a mottled pattern with hues ranging from yellow and orange to tan. While these visual traits might limit some applications requiring uniform appearances, they allow a distinctive, natural look appealing to sustainable product lines emphasizing eco-conscious branding.

The underlying science harnesses the complex properties of mycelial networks combined with wood-derived cellulose nanofibrils. Mycelium contributes the natural water-repellent chemistry and structural intricacy, while CNFs provide mechanical strength and enhance the film’s impermeability to oils and oxygen. This combination leads to coatings that are not only sustainable but also functionally competitive with conventional synthetic polymers used today.

This innovation arrives at a critical juncture when global awareness about the environmental damage wrought by plastics is at an all-time high. Conventional plastic coatings contribute heavily to landfill mass and marine pollution, issues that are difficult to mitigate given their persistence and toxicity. The fungal coating technology, developed using edible and food-safe fungi, offers a biodegradable solution that could integrate into existing manufacturing processes without the need for toxic chemicals or complex synthetic modifications.

Though still at a proof-of-concept stage, the implications for industrial scaling are promising. The basic ingredients—fungal spores, cellulose fibers, and common textiles or papers—are widely accessible. Further research will focus on optimizing growth conditions, improving uniformity, and expanding the durability of the coatings under real-world wear and tear. Additionally, the exploration of other fungal species and nanomaterials may unlock coatings with tailored properties for specialized applications, from luxury textiles to food-grade packaging.

Beyond packaging, this technology intersects with the broader field of biofabrication, where living organisms and their products are engineered to create materials with superior environmental and mechanical properties. Mycelium-based products have recently garnered interest not just for water resistance, but also as biodegradable alternatives in leather-like fabrics, insulation panels, and even as sound absorbers.

Fundamentally, this research underscores nature’s capacity to offer “elegant, sustainable solutions” to pressing material science challenges. As Caitlin Howell eloquently puts it, leveraging the properties of fungi and cellulose nanofibrils could significantly reduce our environmental footprint. By replacing plastic coatings on ubiquitous consumer goods, fungal films might diminish pollution at its source, fostering a future where industrial materials align harmoniously with ecological cycles.

In summary, the creation of edible fungal mycelium coatings demonstrates a novel and practical step forward in the quest for sustainable, biodegradable barriers capable of resisting water, grease, and oils. This aligns well with global sustainability goals and consumer demand for green alternatives. The study characterizes how fungal biology integrated with nanocellulose technology forms functional coatings with minimal environmental impact. As research advances, these naturally derived coatings are poised to disrupt markets reliant on single-use plastics and synthetic polymers, signifying a major stride toward a greener chemical future.

Subject of Research: Sustainable barrier coatings using edible fungal mycelia and cellulose nanofibrils to replace single-use plastic coatings.

Article Title: Growing Sustainable Barrier Coatings from Edible Fungal Mycelia

News Publication Date: 26-Sep-2025

Web References:
https://dx.doi.org/10.1021/acs.langmuir.5c03185

References:
Howell, C., et al. “Growing Sustainable Barrier Coatings from Edible Fungal Mycelia.” Langmuir, 2025. DOI: 10.1021/acs.langmuir.5c03185.

Image Credits: Adapted from Langmuir 2025, DOI: 10.1021/acs.langmuir.5c03185

Keywords:
Chemistry, Sustainability, Natural resources management, Applied ecology