Mechanical Properties of Acetylated Soy Rubber
- David Grewell , Associate Professor of Biological Systems Engineering, Iowa State University
- Kendra Allen, Graduate Student of Biological Systems Engineering, Iowa State University
- Lynne Miller, Professor of Anthropology , MiraCosta College
The production and use of biodegradable plastics made from renewable resources has become an essential area of research. This need for “green” plastics is driven not only by the depletion of petroleum resources but also by the quantities of non-biodegradable and toxic plastics accumulating in landfills and oceans. The use of petroleum-based, non-biodegradable plastics is being reduced through the development of plastic composites, composed of synthetic materials and renewable, biodegradable plant materials. This study assessed the mechanical properties of one such composite composed of a synthetic rubber, Dynaflex, and unmodified defatted soy flour. Previous research had revealed insufficient adhesion between the two materials, caused by the opposing hydrophilic nature of soy flour and hydrophobic nature of Dynaflex. To solve this problem, an acetylation pretreatment of the soy flour was developed to reduce its hydrophilic nature, thus improving its compatibility with the Dynaflex. This study employed an Instron materials testing machine to determine the mechanical properties of the acetylated soy rubber composites produced at various concentrations of acetylated soy flour. Preliminary results demonstrated that the composites containing the acetylated soy flour consistently performed significantly better than the composites with unmodified soy flour. Additionally, the acetylated soy flour composites produced at a 10% concentration demonstrated comparable mechanical properties to the unmodified Dynaflex. However, there was high variance in the mechanical performance among samples of the same composition. This likely occurred because most samples were incompletely homogenized due to inadequate processing methods. Until these processing issues are addressed, a clear understanding of the nature and mechanical performance of acetylated soy flour composites will remain unclear. Despite these issues, the results do show that there is potential for the use of acetylated soy rubber for the same commercial applications as unmodified Dynaflex.