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United States Department of Agriculture

Agricultural Research Service

Research Project: VISCOELASTIC PROPERTIES OF BIO-BASED ELASTOMERIC COMPOSITES

Location: Plant Polymer Research

2009 Annual Report


1a.Objectives (from AD-416)
Develop improved rubber composites and their applications by using bio-based fillers. The research product of this work will aid in generating new markets for agricultural materials, and alleviate the problem of surplus agricultural commodities. This work will also aid in reducing our dependence on petroleum by substituting bio-based fillers from renewable resources for petroleum-based fillers (carbon black).


1b.Approach (from AD-416)
This proposal seeks to develop various economically viable bio-based fillers for rubber composite applications, and their optimum use and processing technology in rubber applications. The proposed experimental approach will investigate factors that can influence the properties of rubber composites such as filler size, filler structure, filler-filler interactions, and filler-rubber interactions. The result will then be used to identify commercially viable bio-fillers and to optimize the composite properties. The proposed experiments will also investigate the mixing and flow behaviors of bio-filler reinforced rubber composites, and develop a commercially viable processing technology for these composites.


3.Progress Report
This goal of this project is to substitute petroleum-based fillers (carbon black) with bio-based fillers from renewable resources to contribute to our material sustainability. In the current development, effects of filler types, filler combinations, and filler treatments on the polymer composite properties were investigated and evaluated for their potential in composite applications. The composites reinforced by wheat gluten, carbon black, and their mixtures were prepared by an internal mixer with various temperatures and processing periods to investigate the change of their moduli with processing conditions. The results showed that the composite moduli prepared by this method were less than those prepared by the freeze-drying method in a previous study. The research indicates that a further improvement of the composite properties may require better bonding between bio-filler and polymer matrix. Phthalic anhydride modified soy protein isolates, both hydrolyzed and un-hydrolyzed, were investigated as reinforcement fillers in rubber composites. The reinforcement effect of modified protein in the composites was significant and the moduli of modified protein composites prepared under a mild acidic condition were similar to that of carbon black reinforced rubber composites. In order to develop a practical process for these bio-based rubber composites, soy/carbon black co-fillers in rubber composites were investigated through collaboration with an industrial company. Ongoing tests showed improvements in some rubber properties. Several carbonized agricultural feedstocks such as distillers dried grains, rice hulls, hominy feed, and corn bran were studied as possible filler material for rubber composites. It was found that the amount of processing required to make these materials worthwhile reinforcement fillers was not cost-effective. Collaboration with other Agriculture Research Service (ARS) scientists and an industrial company that use more effective means of carbonization on waste agricultural feedstocks was pursued and this has led to promising initial results of composites made with these materials as fillers. Studies were conducted to determine the effect of preparation method on the properties of composites of natural rubber filled with defatted soy flour. Samples prepared by vacuum drying and air-drying had modulus up to 50% of samples prepared by freeze-drying. This may provide a more economical means of preparation when only moderate reinforcement is required. A new method of composite preparation using helical inclusion complexes from jet-cooked high-amylose starch was shown to yield significant reinforcement in styrene-butadiene rubber. Acid precipitation of the complexes is believed to form small particles that provide the reinforcement. Further work will be aimed at understanding the reinforcement mechanism and improving composite properties. The current progress contributes to the development of economical and renewable reinforcement fillers for polymer composite applications and has potential scientific and industrial impact for polymer composite developers.


4.Accomplishments
1. Rubber reinforcement with hydrolyzed phthalic anhydride modified soy protein isolates in rubber composites: To increase the sustainability of materials we use today, development of different economical alternatives is required. Hydrolyzed phthalic anhydride modified soy protein isolates is a readily available industrial product and was developed into a useful bio-filler for rubber applications. This work will impact the technology of rubber composites and their applications by providing reinforcing fillers based on renewable agricultural materials instead of petroleum or natural gas derived fillers.


6.Technology Transfer

Number of the New/Active MTAs (providing only)1

Review Publications
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.

Liu, S.X., Kim, J., Kim, S., Singh, M. 2009. The Effect of Polymer Surface Modification on Polymer-protein Interaction via Interfacial Polymerization. Journal of Applied Polymer Science. 112:1704-1715.

Jong, L. 2008. Reinforcement Effect of Soy Protein and Carbohydrates in Polymer Composites. In: Cheng, H.N., Gross, R.A., editors. Polymer Biocatalysis and Biomaterials II. ACS Symposium Series No. 999. Washington, DC: American Chemical Society. p. 86-108.

Jong, L., Peterson, S.C. 2008. Effects of Soy Protein Nanoparticle Aggregate Size on the Viscoelastic Properties of Styrene-Butadiene Composites. Composites Part A Applied Science and Manufacturing. 39(11):1768-1777.

Peterson, S.C., Jong, L. 2008. Effect of Wheat Flour Pre-cooking on the Composite Modulus of Wheat Flour and Carboxylated Styrene-Butadiene Latex. Composites Part A Applied Science and Manufacturing. 39(12):1909-1914.

Last Modified: 9/10/2014
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