Final Report: Development and Demonstration of a Low Embodied Energy, Construction Material that Replaces Expanded Polystyrene and Other Synthetic Materials

EPA Contract Number: EPD10058
Title: Development and Demonstration of a Low Embodied Energy, Construction Material that Replaces Expanded Polystyrene and Other Synthetic Materials
Investigators: McIntyre, Gavin
Small Business: Ecovative Design, LLC
EPA Contact: Manager, SBIR Program
Phase: II
Project Period: May 1, 2010 through April 30, 2012
Project Amount: $225,000
RFA: Small Business Innovation Research (SBIR) - Phase II (2010) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Green Buildings

Description:

Development and demonstration of structural insulating panels comprised of a mycological biomaterial and oriented strand board.

Summary/Accomplishments (Outputs/Outcomes):

Increasingly valuable, nonrenewable, fossil fuel resources are being continuously depleted. As much as 10% of U.S. annual consumption is dedicated to an expanding market of synthetic foam products (Bhattacharje, 2008) including rigid board insulation ($2B/yr). After use, synthetic foams are difficult to recycle and accumulate in municipal landfills, their particulate, non-biodegradable constituents eventually concentrating in tissues of humans and other organisms. The U.S. National Toxicology Program recently reported styrene, a foam precursor, to be a likely carcinogen (Harris, 2011). Consumers and industry are looking for viable renewable alternatives that do not compromise performance or cost efficacy. The purpose of the research, development and demonstration conducted under the Phase II work plan is two-fold: (1) complete industry specific testing to meet regulatory metrics for insulation and structural insulating panels; and (2) collaborate with a commercial partner to quantify performance in relation to the synthetic state of the art.
 
During the 24-month work plan, Ecovative Design LLC developed an advanced biomaterial that is comprised of agricultural byproducts bound by a natural, grown resin (mycelium). The biomaterial institutes regionally sourced agricultural wastes from within the United States, which serve as inexpensive bulking agents that achieve desired thermal, acoustical and structural performance. The vegetative growth of a filamentous fungus, mycelium, is a tenacious bonding agent that is grown in five days and surpasses the strength of most fossil fuel derived foams (expanded polystyrene [EPS] determined during Phase I research). The material development and testing conducted under this statement of work was focused on the development of a rigid board insulation that could serve as the core in a structural insulating panel (SIP). This study compared regionally sourced agricultural waste (oat hull, rice hull, buckwheat hull, and cotton gin waste) and the use of mycelium, opposed to a polyurethane glue, to bind the core to the facing materials (oriented strand board [OSB]).
 
This research tested laminated panels, bound with either glue or mycelium, for compressive strength (ASTM C365), flexure strength (ASTM C393), shear strength (ASTM C273), flatwise-tensile strength (ASTM C297) and accelerated aging (replicating tests of the aforementioned properties, ASTM C481). The buckwheat hull composite consistently had the poorest performance during each of the strength measurements and will not be pursued during commercialization of the construction material platform. The rice hull composite offered superior strength in all loading scenarios tested with the exception of compression when compared to the expanded foam and cotton gin waste composite. In general, the biomaterials stiffened during the accelerated aging analysis, and only the face shear strength exhibited a significant decline post treatment.
 
These results led the team to select the rice hull composite of production scale-up and testing by an industry partner. Full-scale insulating panels were fabricated at Ecovative, with one face from each panel being grown to the OSB laminate and the other bound using polyurethane glue that is traditionally used in industry. The panels were tested to ASTM E72 by Foard Panel in Chesterfield, NH, a leading manufacturer of SIPs in the United States. The results of this test were comparable to the laboratory bench measurement, since the mycelium adhesive strength surpassed the polyurethane glue control in both tests. The adhesives used in SIP construction account for the most expensive consumable in production, thus the mycelium bond is beneficial for reducing the cost of goods sold. The full-scale measurement found the mycelium bound panels to structurally outperform EPS when serving as the core in a SIP. These results, industry feedback and current manufacturing economics have found the SIP industry to be an ideal market entry point, since the biomaterial can serve as a drop in replacement for foams without additional expense to the manufacturer.
 
Additional testing conducted under this Phase II work plan included the measurement of indoor air quality, through the emissions of volatile organic compounds (VOC) and aldheydes (ASTM E1333), and the sound attenuation characteristics (ASTM E1050). Matrix Analytical Labs measured the VOC emissions and all blends tested emitted ≤ 0.44 µg/ft2/min, which is within the California Air Recourses Board (CARB) standards. The biomaterials also were tested for sound attenuation characteristics using an impedance tube, and all blends were found to perform best in the low frequency spectra < 600 Hz.

Conclusions:

The structural insulating panels comprised of Ecovative’'s biomaterial core bound to the OSB laminates with mycelium are comparable, or out-perform, the synthetic state of the art (EPS). Ecovative will be collaborating with industry partners, both domestically and internationally, to verify the measurements in application. Although the panels have been grown in small batches for this development project, this technology fits into Ecovative'’s distributed manufacturing system that is presently growing protective packaging products. Current manufacturing economics, and the potential to remove the expanding glue requirement, will allow Ecovative to introduce the construction biomaterial at a price point comparable to synthetic foams.

Supplemental Keywords:

structural insulating panels, mycelium, fungus, insulation, agricultural waste


SBIR Phase I:

Testing the Viability of Agricultural Byproducts as a Replacement for Mineral Particles in a Novel, Low Embodied Energy, Construction Material  | Final Report