environmental & intl. development portfolio
investigating bioplastics

Material Science and Solid State Chemistry Project at Olin College Timeframe: Spring 2008 Location: Franklin W. Olin College of Engineering, Needham, MA (USA) Key competencies: Investigating bioplastics

From the project introduction:

"With increasing awareness of the costs of our dependence on petroleum, materials scientists are exploring the possibilities of turning renewable plant materials into industrially and commercially viable polymers known as bioplastics. Because they are relatively new, there are a broad number of definitions for what a bioplastic is. One of the most common definitions for bioplastic is plastic in which 100% of the carbon is derived from renewable agricultural and forestry resources. Bioplastics can also be defined in terms of sustainability, however, this remains ambiguous given that much of the source material, like wheat gluten, may not necessarily be produced under environmentally and socially sound conditions. For example, diverting food crops for biotechnology is questionable given that there is a rapidly-developing global food crisis partially tied to the diversion of corn for ethanol biofuel. Also, much of modern agriculture requires the use of a considerable amount of petrochemicals, so pound-for-pound, these “renewable” raw materials may not be as much of an improvement as they seem.

Two of the key plant materials from which bioplastics can be derived are corn starch and wheat gluten, biomolecular polymers that can be transformed into materials with properties similar to conventional petroleum-based plastics through relatively simple processing. We wanted to begin an exploration of the field from the ground up, using two parallel processes—one an activity for children to demonstrate simple cornstarch/oil polymerization and one “more scientific” approach to polymerizing wheat gluten. These processes were obtained from the Utah State University extension service and from research conducted at the Universidad de Huelva in Spain. Hence, we title our project “Flamenco and Salty Mormons.” Throughout this paper, we will refer to the respective methods as the “USU method” and the “Spanish method.”

After making samples using methods based on the two processes, we investigated various aspects of the properties, processing and performance of our bioplastics. The properties we looked at were material composition, structure and bonding. The properties of our polymer samples did not make them attractive candidates for commercial applications compared to petroleum-based plastics. As such, we decided to explore composite processing as a way to give them more strength and potentially broader applicability. We made a composite with cotton fibers and investigated the effects on the mechanical properties of the sample. Finally, the biodegradability, market influence and applicability of the bioplastic types we investigated are discussed as these are extremely important in terms of assessing the usefulness and the potential for acceptance of these types."

 

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