Location: Plant Polymer Research
Title: Natural rubber protein as interfacial enhancement for biobased nano-fillers Author
Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 21, 2013
Publication Date: November 5, 2013
Citation: Jong, L. 2013. Natural rubber protein as interfacial enhancement for biobased nano-fillers. Journal of Applied Polymer Science. 130(3):2188-2197. Interpretive Summary: Commercial rubber contains many types of filler that improve the physical properties so as to meet the ultimate consumer’s needs. Most of the rubbers currently being produced use a great deal of carbon black, a product from the petroleum industry. We have developed a technology that uses agriculturally produced, renewable feedstocks. A useful natural rubber composite was developed by the use of nano-size soy protein aggregates as reinforcement; replacing rubber. Soy protein is an abundant renewable resource and its mechanical/adhesive properties enhance the mechanical properties of rubbers. The size of the reinforcing particles can play a major role in the magnitude of the improvement seen in the rubber. In the current development, the size of soy protein was reduced by an economical process using a high speed mixer, and then blended with natural rubber to form a composite. The working mechanism by which the soy protein improved the properties of the natural rubber was analyzed using various theoretical models. This development will create new markets for soybean products, and will be beneficial to soybean farming industries.
Technical Abstract: Natural rubber was enhanced with soy protein nano-aggregates and carbon black using a hybrid process. The rubber composites reinforced with an optimum amount of soy protein or soy protein/carbon black showed useful tensile properties. The stress-strain behaviors were analyzed with a micro-mechanical model that describes the stress-strain measurements well. The model analysis provides insight into filler network characteristics and entanglement modulus. The composites were also analyzed with both linear and non-linear viscoelastic properties. Temperature and frequency dependent modulus as well as the model analysis of stress softening effect describe the ability of soy protein to constraint polymer chains in the highly filled composites. For the composites reinforced with soy protein, the good tensile properties are attributed to good filler-polymer adhesion through the compatibilization effect of natural rubber protein.