Flow properties of natural rubber composites filled with defatted soy flour

Authors: Byars, Jeffrey; Jong, Lei

Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2008
Publication Date: 2/15/2009
Citation: Byars, J.A., Jong, L. 2009. Flow Properties of Natural Rubber Composites Filled with Defatted Soy Flour. Journal of Applied Polymer Science. 111(4):2049-2055.

Interpretive Summary: In order to have useful properties, rubbers must be reinforced with small filler particles. Petroleum-based carbon black is typically used. Work in our group has shown that many renewable materials are also suitable fillers. Materials prepared with defatted soy flour were studied and their processing characteristics were investigated. This work shows that new uses for agricultural commodities can be created by using defatted soy flour as a filler in natural rubber composites.

Technical Abstract: The linear and nonlinear viscoelastic properties of natural rubber composites reinforced with defatted soy flour were studied. Defatted soy flour is an abundant, renewable commodity, and its rigid nature makes it suitable as a reinforcement phase in rubber composites. At small strain, the elastic modulus of a 30% filled composite was about 20 times higher than the unfilled rubber. Greater reinforcement was observed for carbon black filled composites at a given filler concentration. At high strain, values of the relaxation modulus dropped more rapidly for highly filled defatted soy flour composites. At high shear rates in a capillary viscometer, a small reinforcement effect remained for all composites, and lower die swell was observed for defatted soy flour composites.