DEVELOPMENT OF AGRICULTURALLY-DERIVED BIOPOLYMER COMPOSITES FOR NON-FOOD APPLICATIONS
Location: Bioproduct Chemistry and Engineering Research
Title: Water absorbance and thermal properties of sulfated wheat gluten films
Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 2009
Publication Date: January 27, 2010
Citation: Chiou, B., Robertson, G.H., Rooff, L.E., Cao, T., Jafri, H.H., Gregorski, K.S., Imam, S.H., Glenn, G.M. 2010. Water absorbance and thermal properties of sulfated wheat gluten films. Journal of Applied Polymer Science. 116: 2638-2644.
Interpretive Summary: We produced completely natural superabsorbent materials made from sulfated wheat gluten films. These films are easily produced by dipping the gluten films in concentrated sulfuric acid. The films can absorb up to 30 times their weight in water and can be reused several times without loosing too much of their absorbance capacity. This natural superabsorbent provides an alternative to petroleum-based superabsorbents currently in the market place.
Wheat gluten films of varying thicknesses formed at 30C to 70C were treated with cold sulfuric acid to produce sulfated gluten films. Chemical, thermal, thermal stability, and water uptake properties were characterized for neat and sulfated films. The sulfated gluten films were able to absorb up to thirty times their weight in deionized water. However, this value dropped to 3.5 when the film was soaked in a 0.9% (w/w) NaCl solution. The films were also soaked four times in deionized water and each soaking resulted in reduced water uptake capacity. The temperature of film formation had no effect on final water uptake properties. Also, thinner films had higher concentrations of sulfate groups than thicker films, resulting in higher water uptake values. In addition, sulfated gluten films had comparable glass transition temperatures, but lower thermal stability than neat gluten films.