Submitted to: Journal of Elastomers and Plastics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2010
Publication Date: 3/20/2012
Citation: Peterson, S.C. 2012. Effect of shearing on the reinforcement properties of vital wheat gluten. Journal of Elastomers and Plastics. 43(3): 207-220. Interpretive Summary: Fillers are materials that can be added to rubber to make it stronger. Previous work by our group has shown that commercial wheat flour is an excellent biomaterial filler, but wheat flour has two primary components that could contribute to its reinforcement ability: wheat starch and wheat gluten. The goal of this study was to determine the reinforcement characteristics of wheat gluten by itself, so that we can judge which component of wheat flour is the better reinforcement agent. It was determined that wheat gluten only yielded one tenth of the reinforcement properties as that of wheat flour. Therefore, now we know that the excellent reinforcement properties of wheat flour are due primarily to the wheat starch present. This work would impact the food and rubber processing industries, and could bring about the production of strong rubber composites using wheat flour and/or wheat starch, which is cheap and renewable, and reduce the use of carbon black, which is obtained from the burning of fossil fuels.
Technical Abstract: The reinforcement properties of vital wheat gluten as a biomaterial filler for a carboxylated styrene-butadiene rubber were examined to assess its effectiveness as a filler for carboxylated styrene-butadiene rubber composites. Composites were formulated using 10-40% vital wheat gluten by mixing aqueous suspensions of the gluten and rubber, then freeze-drying and compression molding the resulting composite. Rheological experiments indicated that vital wheat gluten reinforced the rubber up to a factor of roughly 30. Subjecting the gluten suspension to high shearing to reduce the particle size yielded slight increases in reinforcement at pH 4.9, but this effect was essentially eliminated at pH 4.1. Heat denaturing of the gluten = 110 deg C played a significant role in the overall composite strength. Vital wheat gluten was studied in order to determine its relative merit as one of the two reinforcing components of wheat flour (the other being wheat starch), and its reinforcing ability was a factor of 10 weaker than wheat flour, indicating that wheat starch is a much more effective biomaterial filler.