Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract only
Publication Acceptance Date: 10/15/2012
Publication Date: 11/12/2012
Citation: Holt, G.A., Mcintyre, G., Bayer, E. 2012. Optimizing biomass blends for manufacturing molded packaging materials using mycelium. Proceedings of The Association for the Advancement of Industrial Crops 24th Annual Meeting. November 12-15, 2012, Sonoma, CA. p. 44. Interpretive Summary:
Technical Abstract: Polystyrene is one of the most widely used plastics and is commonly produced in three forms: 1) Extruded polystyrene – disposable utensils, CD/DVD cases, yogurt containers, smoke alarm housing, etc.; 2) Expanded polystyrene foam – molded packaging materials and packaging "peanuts"; 3) Extruded polystyrene foam – insulation boards. Extruded polystyrene foam is commonly sold under the name of StyrofoamTM. Polystyrene packaging and insulation is a multibillion dollar a year industry. Since polystyrene is non-biodegradable, a biodegradable material that is eco-friendly was sought as a substitute for packaging and insulation board consumers. The material produced from a process, developed by Ecovative Design, LLC, involved growing fungal species on biomass substrates to produce an eco-friendly packaging product (EcoCradleTM) and insulation panels (GreensulateTM). Previous research had shown desirable physical and mechanical properties from molded packaging materials produced with cotton gin byproducts (CGB) as a substrate. However, when CGB was blended with other biomass substrates, physical and mechanical properties were improved. The objective of this research was to evaluate and determine the optimal biomass blend(s) producing the best overall physical and mechanical properties for composites produced using Ecovative’s technology. Eight biomass substrates, kenaf fibers, kenaf pith, hemp pith, switchgrass, sorghum stover, rice straw, flax shive, and CGB were evaluated for optimal performance using twenty-one response variables. Evaluations were conducted on samples produced using a fungus selected from the Ganoderma tsugae group. All biomass materials were processed at USDA-ARS, Cotton Production and Processing Research Unit in accordance with predetermined particle size requirements. The substrates were sent to Ecovative’s facility in Green Island, NY, where samples were made from predetermined blends of each material. Properties evaluated included: density, strength (compressive and flexural), dimensional stability, modulus of elasticity, energy absorption, thermal conductivity, and accelerated aging. Results from a D-Optimal mixture design revealed different optimal blends involving two to four biomasses, depending on end-user specifications and properties deemed most desirable. The CGB were most effective when dynamic energy absorption and compressive strength were of interest. Sorghum stover was a good ingredient for energy absorption when strength was not as desirable. Kenaf pith was a primary ingredient when lower density was valued. Cost of the biomass was not a response variable in determining the optimal blends.