Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/17/2006
Publication Date: 9/10/2006
Citation: Jong, L. 2006. Carboxylated styrene-butadiene rubber composites reinforced by defatted soy flour and carbon black co-filler. Polymer Preprint 2006. 47(2):481-482. Interpretive Summary: Defatted soy flour (DSF) is an inexpensive renewable commodity. DSF is a soy product after soybean oil is removed from soybean flakes and is a raw material for the production of soy protein concentrate and isolate. In many rubber related applications, rubber products are filled with reinforcement materials. Current development is to use a renewable material with cost/performance benefits as a rubber reinforcement material. The results indicate that DSF is a potential substitute for non-renewable carbon black. 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: The rubber composites reinforced by a mixture of defatted soy flour (DSF) and carbon black (CB) are investigated in terms of their dynamic shear modulus. DSF is an inexpensive and plentiful renewable material from soybean after soybean oil is removed. DSF contains soy protein and soy carbohydrate. The aqueous dispersions of DSF and CB were first mixed at three different ratios (CB:DSF = 3:1, 1:1, and 1:3) and then blended with carboxylated styrene-butadiene latex to form rubber composites by freeze-drying and compression molding method. Thermal mechanical measurements of G’ show that DSF composites have a significantly greater G’ than CB composites within the rubber plateau region. Comparing with CB composites, all co-filler composites show a greater elastic modulus in the rubber plateau region. Although the composites with higher DSF content have higher G’, the recovery behavior favors a higher CB content. A compromise between elastic modulus and recovery behavior appears to be the composites with 50% to 75% substitution of CB with DSF. This study shows the use of more economical DSF to partially substitute CB as the reinforcement co-filler produces rubber composites with enhanced shear modulus.