Grantee Research Project Results
Final Report: Eco-Friendly Golf Tees Filled with Corn-Based DDGS
EPA Grant Number: SU833516Title: Eco-Friendly Golf Tees Filled with Corn-Based DDGS
Investigators: Tatara, Robert A. , Ziemer, Norbert L. , DiOrio, Nicholas R.
Institution: Northern Illinois University
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2007 through August 31, 2008
Project Amount: $9,933
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2007) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Chemical Safety , P3 Awards , Sustainable and Healthy Communities
Objective:
The overall purpose of the proposed study was to formulate a novel biomaterial using corn processing co-products, DDGS. This project enhances sustainability by providing alternative, higher value utilization for corn processing co-products. This bio-based material is less costly than current biodegradable resins. Additionally, it can reduce the amount of resin manufactured from petroleum raw materials in plastic products. Thus “green” plastics are more competitive; the planet’s oil reserves are conserved; and the amount of plastic disposed of, at the end of a product’s useful life, is reduced. An additional benefit of such a biofilled material is to increase the rate of biodegradability of the plastic with the potential of creating a “greener” plastic. 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.
The goal was to create a novel bio-product based on corn-derived DDGS in a commercially viable form: Green Tee™. DDGS, 10% to 50% by weight, was blended with a commercially-available biodegradable corn starch plastic resin and injection molded to develop test golf tees and other shapes for mechanical testing. The tees and blends were mechanically evaluated: tensile strength, impact strength, material stiffness, ductility, and hardness. In addition to the mechanical properties, other material qualities such as biodegradability, surface finish, color, and general appearance were evaluated as these are also important. The test results were extrapolated to optimizing the blending and molding conditions needed to produce products.
Summary/Accomplishments (Outputs/Outcomes):
Figure 1 presents the ultimate tensile strength for the DDGS/corn starch blends, including the 100% starch control case. It is seen that, as expected with any filler, the presence of DDGS lowers the material’s strength. Using 25% and 10% DDGS reduces the corn starch’s strength by 45% and 25%, respectively. There is not significant difference between blending in flaked or powdered DDGS.
Figure 1. Ultimate Tensile Strength of DDGS and Corn Starch Blends
The stiffness, as measured through the Young’s modulus and shown in Figure 2, decreases 15% for 25% flake or powder DDGS compared to the control. But 10% DDGS increases the stiffness approximately 10%. There is not significant difference between the flaked and powdered filler forms. Figure 3 presents the hardness and indicates that the DDGS blends are only slightly softer than the pure corn starch control. Also available in the figure is wood data; all corn starch blends are somewhat harder that white pine. The flexibility of the biomaterial is given in terms of its elongation to break. This is expressed by the percentage that the material strains (stretches) until it fractures. Figure 4 indicates that all corn starch formulations tested are rather brittle with less than 5% elongation. No consistent trends were found although 25% flake or powder showed less flexibility than the control. However, the flaked 10% DDGS blend exhibited better strain than the zero DDGS case; it is possible that the larger DDGS particle size held the corn starch matrix together longer. The 10% powdered blend was less ductile than pure corn starch.
Figure 2. Young’s Modulus for DDGS and Corn Starch Blends
Figure 3. Surface Hardness of DDGS and Corn Starch Blends
Figure 4. Elongation of DDGS and Corn Starch Blends
The resistance to a sudden blow or force (impact resistance) is shown in Figure 5. In these data, actual golf tees were fabricated and impact tested by swinging a pendulum-weighted hammer and breaking the tee. All the golf tees are relatively brittle, regardless of the material formulation. Also in Figure 5 are test results from a biodegradable golf tee already on the market (“Existing Product”), but this tee is relatively costly since it is a 100% biocomposite material. With starch, the addition of DDGS does increase brittleness but there is still adequate impact strength in the material as verified in field tests with golfers. Most importantly, Figure 6 demonstrates the accelerated biodegradability as the DDGS content increases. For these tests, a 50% powder blend was also available. The Green Tee™ exhibited 30% to 50% better biodegradability compared to the tee available in the marketplace. Both types of tees were more biodegradable than wood or pure corn starch ones. The performance of 35% flake, 25% powder and 5% flake, and 25% powder is about the same.
Figure 5. Relative Impact Resistance of DDGS and Corn Starch Blends
Figure 6. Biodegradability of DDGS and Corn Starch Blends
Conclusions:
This project demonstrates the feasibility of using a corn starch resin with a corn-based DDGS filler material to make a commercially-viable product: the Green Tee™ (Figure 7). Filler concentrations between 10% and 35% represent reasonable values as sufficient mechanical strength is retained and DDGS replaces a proportionally greater amount of the more expensive resin. An optimal value may be 25%. Qualitative inspection of the golf tees shows a good smooth surface, typical of injection-molded parts. The DDGS also provided a rich, wood-like color to the corn starch resin which is white in its original state. The general appearance resembles commercially-available tees in the marketplace.
This project definitely shows potential to effect positive impacts in moving towards sustainability, by reducing the need for petroleum inputs in plastics as well as by potentially improving the end-of-life biodegradability of plastic products. It is an adaptation of a current material to a novel use.
Figure 7. Green Tee™ Product Manufactured and Packaged at Northern Illinois University
Proposed Phase II Objectives and Strategies:
Further work should include improving the properties of corn-based DDGS with starch resin blends, seeking other biodegradable resins compatible with DDGS, and obtaining other design properties for such bio-based “green” materials. Additional design properties may be thermal, optical, electrical, density, or other kinds. Likewise research ought to identify more products suitable for incorporating DDGS. The goal is to develop information and design data so that manufacturers will be able to incorporate DDGS into existing biodegradable products, promoting the use of these resins, and advancing the eco-friendly products.
Supplemental Keywords:
green chemistry, waste reduction, waste minimization, environmentally conscious manufacturing, biomaterials, biofillers, biobased plastics, green plastics, biodegradability, biocomposites, plastics technology, sustainability, renewability,The 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.