Evaluation of physico-mechanical properties of mycelium reinforced green biocomposites made from cellulosic fibers

Authors: ZIEGLER, A - Consultant; BAJWA, S - North Dakota State University; Holt, Gregory; MCINTYRE, G - Ecovative Design, Llc; BAJWA, D - North Dakota State University

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2016
Publication Date: 12/31/2016
Citation: Ziegler, A.R., Bajwa, S.G., Holt, G.A., McIntyre, G., Bajwa, D.S. 2016. Evaluation of physico-mechanical properties of mycelium reinforced green biocomposites made from cellulosic fibers. Applied Engineering in Agriculture. 32(6):931-938.

Interpretive Summary: Natural fibers from hemp and cotton were used in a novel process patented by Ecovative Design, LLC to manufacture biocomposites. The natural fibers were the innoculated with fungus and grown into specific shapes. The manufacturing process involves sterilizing the natural fibers and then innoculating the material with a specific fungal species. The fungus grows over a 2 to 3 day period and then the material is removed from the tool and placed in a dryer for 6 hr until fungal growth has terminated and the piece is dry. The fungal/agricultural fiber biocomposite is a 100% biodegradable material designed to replace fossil-fuel derived polystyrene molded packaging. This study looked at physical and mechanical properties of biocomposites made using Ecovative's process. The biocomposites were evaluated for a wide variety of properties ranging from density to water absorption. Results showed high water resistance of all biocomposite pieces, due in large part to the water resistant nature of the fungal mycelium which coated the exterior of all the test samples. Surface hardness numbers indicated biocomposites with highly deformable surfaces. Compression testing indicated small resistance of the biocomposites to compression indicating the material is well suited for applications such as packaging, footwear insoles, and applications that require low compressive strengths. Overall, the biocomposites performed well and the testing revealed changes that would need to be made to enhance the materials.

Technical Abstract: Biodegradable and sustainable feedstock’s are increasingly replacing petroleum based materials commonly used for single or multi use packaging applications. A study was conducted to evaluate the potential of an innovative biocomposite material patented by Ecovative Design LLC for use in commercial products and packaging. The biocomposite material utilizes the fungus mycelium as a matrix to bind a cellulosic plant fibers. The test samples were manufactured with different fiber-fungal strain combinations and using cotton ginning waste and hemp pith as core material and fiber fabric on the surface. The physico-mechanical properties of the biocomposites evaluated included specific gravity, surface hardness, water absorption, coefficient of linear thermal expansion (CLTE), and resistance to tension and compression stress. The density profile results indicated that the material is extremely light, buoyant, and highly hydrophoblic. Surface hardness test showed that the material has a soft outer surface with high elasticity. The tensile and compression properties showed the material can be used in targeted packaging applications where light weight, resiliency and biodegradability are desirable.