Submitted to: Proceedings of American Chemical Society National Meeting
Publication Type: Proceedings
Publication Acceptance Date: December 2, 2006
Publication Date: March 25, 2007
Citation: Jong, L. 2007. Green composites of natural rubber and defatted soy flour. In: Proceedings of Polymeric Materials: Science and Engineering. American Chemical Society National Meeting, March 25-29, 2007, Chicago, Illinois. 96:478-479. Interpretive Summary: Natural rubber is an important class of rubber material for many industrial applications. Defatted soy flour (DSF) is a soy product after soybean oil is removed from soybean flakes. In many rubber related applications, rubber products are filled with reinforcement materials. Current development demonstrates a green composite of natural rubber and DSF from agricultural sources is possible. This development will be of general interest to technologists developing new rubber products and will be beneficial to soybean farmers by creating new markets for soybean products.
Technical Abstract: Viscoelastic properties of natural rubber (NR) composites reinforced by defatted soy flour (DSF) are investigated. DSF is an abundant renewable commodity and has a lower material cost than carbon black (CB). DSF contains soy protein, soy carbohydrate, and soy whey. Aqueous dispersion of DSF was blended with natural rubber latex to form rubber composites by freeze-drying and compression molding method. A 40% DSF reinforced composite exhibited about a 60-fold increase in the shear elastic modulus compared with unfilled natural rubber, showing a significant reinforcement effect by DSF. The effect, however, is lower than the carboxylated styrene-butadiene rubber composites reported earlier, indicating a significant effect of rubber matrix. Mixtures of DSF and CB at three different ratios were also investigated as co-fillers. The co-filler composites have elastic moduli that were between those of DSF and CB reinforced composites. The recovery experiments indicated the co-filler composites with a higher CB content have a better recovery behavior, which however can not be predicted from the recovery behavior of the single filler (DFS and CB) composites.