Grantee Research Project Results
Final Report: Sustainable Plastics: Designing and Demonstrating Renewable, Biodegradable Products Made of Soy Protein-based Plastics
EPA Grant Number: SU833514Title: Sustainable Plastics: Designing and Demonstrating Renewable, Biodegradable Products Made of Soy Protein-based Plastics
Investigators: Osswald, Tim , Ralston, Brian , Knauf, Stefanie , Day, Travis
Institution: University of Wisconsin - Madison
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2007 through August 31, 2008
Project Amount: $10,000
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 Awards , P3 Challenge Area - Chemical Safety , Sustainable and Healthy Communities
Objective:
Plastics based on fossil fuels present environmental problems related to their disposal at the end of their life cycle. Plastics based on renewable resources, such as soybeans and corn, offer alternatives to fossil fuel based plastics. The objective of the research undertaken in Phase I was to demonstrate the viability of plastics made of soybean protein. To this end, several formulations of soy protein-based plastics were screened for mechanical and viscosity properties. The formulations included glycerol as a plasticizer, cornstarch as a second biopolymer in addition to soy protein itself, and other components. One area of application for soy protein based plastics is extruded tubular profiles. The design and construction of an extrusion die was undertaken in partnership with Teel Plastics (Baraboo, WI) to produce prototype tubes as a proof of concept prior to adoption by industrial partners.
Summary/Accomplishments (Outputs/Outcomes):
We have found that soy protein plastics have flow properties that are comparable to fossil fuel-based plastics. Soy plastics are processed at much lower temperatures, however, yielding energy savings over synthetic plastics during processing. These comparable flow properties make soy protein plastics a viable drop-in replacement for synthetic resins; no new capital investments by plastics manufacturers are required to utilize soy protein plastics in their products.
Five formulations of soy protein plastics were screened for viscosity and mechanical properties. The different formulations tested the effects of various ratios of soy protein to cornstarch, the addition of sodium sulfite and the addition of a titanate coupling agent. The material with the titanate coupling agent and a low soy protein to cornstarch ratio performed best in terms of high strength, high stiffness and high elongation at break. All formulations of soy protein plastic were sensitive to humidity and water – a boon to biodegradability and flushability of disposable items.
Conclusions:
Soy protein plastics have the potential to offer a sustainable alternative to fossil fuel based plastics for some applications, including nursery tree tubes, tampon applicators, food service trays, packaging and more. The properties of these materials require only slight improvement to become competitive with commodity synthetic resins like polyethylene and polystyrene. Further research into blending soy protein with other bio-based materials, including poly(lactic acid) (PLA), cornstarch, and natural fibers is required to achieve the necessary properties.
Proposed Phase II Objectives and Strategies: In Phase II, we propose to continue and expand upon the work of Phase I. Soy protein-PLA blends will be screened for mechanical properties and water sensitivity. Reported results in the literature suggest soy protein-PLA blends have properties rivaling commodity synthetic resins without the water sensitivity of the soy protein-cornstarch materials screened in Phase I. Soy protein-PLA blends would be compostable. These materials would be extruded into tubes and sheets, with the sheets being further processed via thermoforming into various shapes (e.g., compostable food trays and packaging).
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 8 publications | 1 publications in selected types | All 1 journal articles |
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Ralston BE, Osswald TA. The history of tomorrow’s materials: protein-based biopolymers. Plastics Engineering 2008;64(2):36-40. |
SU833514 (Final) |
Exit Exit |
Supplemental Keywords:
Soy protein, cornstarch, plastic, biopolymer, extruson, injection molding, thermoforming, sustainable,, Sustainable Industry/Business, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Technology for Sustainable Environment, Sustainable Environment, Environmental Chemistry, Chemistry and Materials Science, Chemicals Management, biodegradable materials, biodegradable plastics, pollution prevention, plastics manufacturing, renewable resource, soy protein-based plastics, alternative materials, 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.