Grantee Research Project Results
Final Report: Use of a Corn Processing Co-Product as a Biofiller Material in a Plastic Resin
EPA Grant Number: SU832478Title: Use of a Corn Processing Co-Product as a Biofiller Material in a Plastic Resin
Investigators: Tatara, Robert A. , Bremer, Nathan , Olszewski, Robert , Suraparaju, Srikrishna
Institution: Northern Illinois University
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2005 through May 30, 2006
Project Amount: $9,933
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2005) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Chemical Safety , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
Plastics (polymers) play an important role in our lives and have many properties that satisfy consumers’ needs from the most basic to the very complex. In the United States, plastics are used in large volumes in both industrial and commercial applications and have become an indispensable commodity in all aspects. Plastics are used to manufacture everyday products such as bottles, cups, tubes, bags, containers, household items, and furniture. The increased use of plastics can be credited to their broad range of properties and design technologies. Plastics provide a wide variety of consumer benefits unsurpassed by any other materials.
The plastics industry in the United States is one of the five largest industries, earning more than $320 billion in annual sales and employing 1.5 million people. This industry continues to grow as plastics replace more traditional materials such as metals, wood, ceramics, and glass. The success of the plastics industry has significantly impacted the environment; the relative inertness of disposable (one-time use) products, along with products that have exceeded their usefulness and are discarded, leads to pollution. Solid plastic wastes must be dealt with on a large scale. Some plastics are recycled, although the effort requires collection, handling, sorting, cleaning, and remanufacture preparation. There is substantial cost associated with recycling, and not all plastics are recyclable. Another option is incineration, a process in which the plastic is burned as fuel to generate electricity. However, issues such as hazardous gas emissions, global warming, greenhouse gases, ash disposal, and heavy metals make incineration a difficult and costly option. A third option is landfill disposal. Plastics currently compose a significant volume of landfill wastes.
Adding certain biological materials as fillers to plastics can provide an alternative, higher value utilization for such materials and reduce the amount of resin, manufactured from petroleum raw materials, in plastic products. Thus the planet’s oil reserves are conserved and the amount of plastic disposed of, at the end of the product’s useful life, is reduced. There is also the possibility to enhance any existing biodegradability or provide biodegradability where none had previously existed. For this study, it was proposed to use corn processing co-products, such as DDGS, as a biofiller in a plastic resin to form “CornPlastic.”
The United States currently produces millions of tons of grains co-products, mostly from corn from the manufacture of ethanol. Corn processing co-products arise from dry milling or wet milling of corn in the production of ethanol. They are the remnants after the starch fraction of corn is brewed with yeasts and enzymes to produce ethanol and carbon dioxide. They are considered a low value commodity to be disposed of at whatever the market price; the typical use is in farm animal feeds. Corn processing co-products from milling include distillers dried grains with solubles (DDGS). However, this co-product, once dried, represents a potential biofiller. Furthermore it should be noted that the co-product material contains significant fiber content; approximately one-third of DDGS is fiber. The presence of fiber in the dried solid content in combination with a resin may improve the mechanical properties of plastic products by creating a biocomposite, as with wood plastic composites. DDGS, as a biofiller, provides an additional market for the agriculture industry and farmers, especially those in corn farming. Thus there is the need for higher value utilization of these corn co-processing co-products. The successful objective of this project was to formulate a novel biocomposite material based on DDGS called CornPlastic. Overall, this work impacts sustainability on a global level by minimizing the environmental impact of plastic products while lowering costs and conserving non-renewable resources.
Summary/Accomplishments (Outputs/Outcomes):
To determine the feasibility of blending the DDGS with a resin, some initial tests were completed to ensure that the biofiller and resin were compatible. The tests consisted of compression molding some representative blends of 25%, 50%, 75%, and 90% DDGS into 3.375” diameter drink coasters. Compatibility criteria included plastic part appearance, moldability, and minimum mechanical strength. With thermosets being more commonly filled than thermoplastics, the resin tested was phenolic. Additionally, phenolics represent the most commonly compression molded resins. With the combination of a common resin with a common molding process, these results are of immediate and practical use to manufacturers and the plastics industry.
After the compatibility studies, to effectively utilize the DDGS biofiller, initial mechanical properties were quantified. To make the results comparable to existing data and reportable, a tensile bar mold was created for tensile specimens; compression molding was used to create tensile bar specimens for mechanical strength testing. The concentration of the biofiller was varied by weight, to form biocomposites. Then for each blend, the mechanical properties were evaluated through standard tensile testing; testing adhered to ASTM standards. From the testing, the general strength or ability of the CornPlastic to withstand pulling forces (tensile strength), the Young’s modulus (which indicates the stiffness of the material), and the flexibility or stretching potential of the CornPlastic were measured
As expected, the data indicate a general downward trend in mechanical properties. However, for DDGS concentrations up to 50%, the strength and flexibility decrease is only 20% to 40%; in fact the Young’s modulus at low DDGS content appears to be unchanged resin/corn-based DDGS filler material. Filler concentrations of 25% to 50% represent reasonable values as sufficient mechanical strength is retained and DDGS replaces a proportionally greater amount of the resin. At DDGS > 75%, mechanical strength is reduced by over 60% and stiffness by about 50% although enough strength remains to support an application such as the molded drink coasters.
Conclusions:
This study has demonstrated the viability of a phenolic resin/corn-based DDGS filler material. Filler concentrations of 25% to 50% represent reasonable values as sufficient mechanical strength is retained and DDGS replaces a proportionally greater amount of the resin. These data also have established the bounds of the testing parameters.
This project has been successful in producing a novel biocomposite material: CornPlastic. Mechanical testing has demonstrated that at 25% to 50% DDGS content this biocomposite retains 60% to 80% of the strength of pure plastic. Drink coasters have been fabricated from the CornPlastic. People benefiting include agriculture industry personnel and farmers, especially those in corn farming. The work is easily transferable to other grains and agricultural sectors in the U.S. and across the world. The success of the project was due to the contributions of students from two engineering disciplines (Mechanical Engineering and Engineerin.
Supplemental Keywords:
green chemistry, waste reduction, waste minimization, environmentally conscious manufacturing, biomaterials, biofillers, green plastics, biodegradability, biocomposites, plastics technology, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Sustainable Industry/Business, Environmental Chemistry, Sustainable Environment, Technology for Sustainable Environment, Chemicals Management, pollution prevention, Environmental Engineering, biodegradable plastics, cleaner production, environmentally conscious manufacturing, environmental sustainability, alternative materials, biocomposite, biofiller, biodegradable materials, environmentally friendly green products, plastics manufacturing, green chemistryThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.