Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: VISCOELASTIC PROPERTIES OF BIO-BASED ELASTOMERIC COMPOSITES

Location: Plant Polymer Research

2006 Annual Report


1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter?
New and expanded markets are needed for annually renewable crops, such as corn and soybeans, because of their continued surplus production, and their depressed values. In addition, the gradual replacement of petroleum-based materials with renewable materials can ease the economic transition from a petroleum-based to a nonpetroleum-based economy because of reducing world petroleum reserves. Rubber composites are used as components in various products, and reinforcing fillers constitute a multi-billion dollar a year industry worldwide. Rubber composites for energy absorbing applications include devices that absorb vibration energy, such as rubber tires, rubber bumpers, and rubber feet. Currently, carbon black dominates the reinforcing fillers’ market used in elastomer applications. However, carbon black is petroleum-based, non-renewable, non-sustainable, and non-biodegradable. Projected 2006 worldwide carbon black volume used in rubber is 8.05 million metric tons. Roughly 70% of all carbon black is used in tire applications. Agricultural products (e.g. carbohydrates, proteins) and their blends possess several desirable characteristics (e.g. rigidity, self-association, renewability, low cost, and biodegradability) that make them attractive candidates for use as rubber reinforcing fillers. This has been demonstrated by recent proof-of-concept experiments in our lab, which show that, relative to carbon black, defatted soy flour provides stronger reinforcement at a much lower cost. However, successful development of high performance and low cost bio-based fillers for industrial rubber applications requires a thorough understanding of how variables such as particle size, aggregation, and surface chemistry of fillers made from various agricultural sources (soy, corn, wheat, etc.) affect the viscoelastic properties of the final rubber composites in both the melt and solid states. Our limited publications on bio-based fillers have received the attention of major manufacturers in the rubber industry, who have requested more information and materials for testing. It should be noted that several companies have programs to develop biomaterials for tire applications. For example, the Goodyear Corporation has patents claiming the use of starch as a partial replacement of carbon black in tire applications. This indicates the industrial interest in using biomaterial for this application. While our initial focus will be on tire applications, the anticipated biomaterial technology is expected to apply in other non-tire applications such as rubber sealing devices, conveying devices, and other energy absorbing devices. The special problems to be solved by this research are (1) incorporating bio-based materials as reinforcement for elastomeric composites used in tire applications, and (2) processing bio-based elastomeric composites into various products.

This work is relevant to the farmers growing soybean, wheat, and corn, as well as the grain processors who will benefit by realizing increased value for their products. The impact of this project includes: (1) new and expanded markets for soy products and cereal grains, (2) a reduction of federal outlays for surplus commodity support, and (3) an improvement of the profitability of American agriculture. This project will also contribute to sustainability and environmental quality, as well as the reduction of our consumption on petroleum and natural gas through partial replacement of carbon black with biomaterial fillers. Other customers of this research are the companies that produce and consume products containing reinforced rubber parts (e.g. rubber gaskets, automobile tires, rubber rollers, conveyer belts, toys, bumpers, footwear, sealants, etc.), and rubber molding manufacturers will be beneficiaries of this work.

The proposed research supports National program 306, Quality and Utilization of Agricultural Products component 1.1.1, which includes the search for new processes, uses, and value-added products from undervalued agricultural commodities. This project will result in technology leading to a broad range of new composite applications for soybeans, corn, and wheat. This research will lead to expanded value-added applications for carbohydrates and proteins in rubber composites for tire applications. The biomaterial reinforced rubber composites will meet or exceed the performance of existing rubber composites at a competitive price. The research will also foster a greater understanding of the structure-property relationships of bio-based composites and further improve their properties and marketability.


2.List by year the currently approved milestones (indicators of research progress)
Year 1 (FY 2006) 1. Soy-based fillers – complete a database on the structure/property of soy-based fillers and their composites.

2. Soy-based fillers – complete a database on the effect of composition and processing parameters on the flow properties of composites reinforced by soy-based fillers.

Year 2 (FY 2007) 1. Soy/carbon black co-fillers – develop the co-filler reinforced rubber composites that have an elastic modulus greater than their carbon black filled alternative.

2. Soy/carbon black co-fillers – determine the effect of processing parameters on the flow properties of composites reinforced with soy/carbon black co-fillers.

Year 3 (FY 2008) 1. Wheat-based fillers - complete a database on the structure/property of wheat-based fillers and their composites.

2. Soy/carbon black co-fillers – develop a cost-effective processing method and rubber composites by adjusting both the composite formulation and processing parameters. Prototype tests by industrial partners.

Year 4 (FY 2009) 1. Wheat/carbon black co-fillers - develop the co-filler reinforced rubber composites that have an elastic modulus greater than their carbon black filled alternative.

2. Wheat-based fillers – determine the effect of composition and processing parameters on the flow properties of wheat-filled composites. Pilot-scale tests and production plant trial by industrial partners.

Year 5 (FY 2010) 1. Corn-based fillers - complete a database on the structure/property of corn-based fillers and their composites.

2. Corn-based fillers – determine the effect of composition and processing parameters on the flow properties of corn-filled composites. Commercialization of bio-filler reinforced rubber composites by industrial partners.


4a.List the single most significant research accomplishment during FY 2006.
Soy spent flakes reinforced rubber composites: Soy spent flakes is a by-product or residue in commercial soy protein extraction process. Soy spent flakes has minimal commercial value in the present time. A treated soy spent flakes was used to reinforce rubber composites and a significant reinforcement effect was found. This development will lead to cost effective rubber products. This information, which is presently not available in the scientific literature, is essential in developing cost-effective composites and applications. This research falls under National Program 306, Quality and Utilization of Agricultural Products, 4.1.1.1 New Uses, Products, and Materials.


4b.List other significant research accomplishment(s), if any.
This research falls under National Program 306, Quality and Utilization of Agricultural Products, 4.1.1.1 New Uses, Products, and Materials. Reinforcement mechanism of the combination of soy protein and soy carbohydrate: Composites reinforced by the combination of soy carbohydrate and soy protein showed a significant reinforcement effect. Soy protein concentrate contains ~70% protein and insoluble carbohydrate showed a greater reinforcement effect than protein dominated soy protein isolate or carbohydrate dominated soy spent flakes. This synergistic reinforcement effect is explained in terms of stronger filler network and filler immobilized polymer network. This study indicates soy filler with a certain combination of soy carbohydrate and soy protein can yield a greater reinforcement effect in rubbers than soy filler dominated by carbohydrate or protein. This information is useful in optimizing the performance and cost of rubber products.

Determine the effect of preparation methods on the viscoelastic properties of polymer composites reinforced by soy spent flakes: In rubber reinforcement, filler network structure has significant effect on rubber modulus. Different preparation methods may produce different filler network structures and lead to different reinforcement effect. In this study, more insight on the reinforcement mechanism is obtained by comparing different preparation methods - casting versus freeze-drying. Soy spent flakes (SSF) as filler used in this study is mostly a soy carbohydrate fraction in soybean and carbon black (CB) is also included as a comparison. Comparison between the freeze-drying and casting method indicates filler network related structure in the composites prepared by freeze-drying method is more elastic than that by casting method and can be explained by the model of polymer mediated filler network. The stress softening effect of SSF and CB composites again indicates the composites prepared by freeze-drying method have better recovery behavior than that by casting method due to their more elastic filler network structure. This information is useful in optimizing the processing method.


4c.List significant activities that support special target populations.
None.


4d.Progress report.
None.


5.Describe the major accomplishments to date and their predicted or actual impact.
This research falls under National Program 306, Quality and Utilization of Agricultural Products, 4.1.1.1 New Uses, Products, and Materials. Cost effective rubber composites were developed by reinforcing rubbers with inexpensive soy spent flakes. Soy spent flakes is a by-product or residue in commercial soy protein extraction process. Soy spent flakes has minimal commercial value in the present time. A treated soy spent flakes was used to reinforce rubber composites and a significant reinforcement effect was characterized.

Rubber composites with a very significant reinforcement effect were developed through the combination of soy carbohydrate and soy protein. Soy protein concentrate contains ~70% protein and insoluble carbohydrate showed a greater reinforcement effect than protein dominated soy protein isolate or carbohydrate dominated soy spent flakes.

Knowledge leading to the optimization of processing methods was developed by characterizing the reinforcement mechanism of rubber composites through the comparison of different preparation methods - casting versus freeze-drying. In rubber reinforcement, filler network structure has significant effect on rubber modulus. Different preparation methods may produce different filler network structures and lead to different reinforcement effect.


6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
The reinforcement mechanism and the method of using soy-fillers in rubber composites were transferred to a rubber company who had completed a successful test by incorporating soy-fillers in their rubber formulations.

The findings of this research were also transferred to other scientists working in academia, government, and industry throughout the year by the timely reporting of our research in scientific journals and presentations at various national scientific meetings.

It is expected that technology from this CRIS will become available for transfer to industry towards the end of FY 2008.


7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
None.


Review Publications
Jong, L. 2005. Rubber composites reinforced by soy spent flakes. Polymer International. 54(11):1572-1580.

Jong, L. 2005. Characterization of defatted soy flour and elastomer composites. Journal of Applied Polymer Science. 98(1):353-361.

Jong, L. 2005. Viscoelastic properties of ionic polymer composites reinforced by soy protein isolate. Journal of Polymer Science Part B: Polymer Physics. 43(24):3503-3518.

Jong, L. 2005. Synergistic reinforcement effect of soy carbohydrate and soy protein in polymer composites. Proceedings of American Chemical Society National Meeting. 93:612-613

Jong, L. 2006. Effect of preparation methods on the viscoelastic properties of polymer composites reinforced by soy spent flakes. Proceedings of American Chemical Society National Meeting. 47(1):125-126.

Last Modified: 7/30/2014
Footer Content Back to Top of Page