Location: Plant Polymer Research
2021 Annual Report
Objectives
The goal of this research project is to use a wide range of technological approaches in the utilization of agricultural byproducts and feedstocks to improve functionalities of protein/carbohydrate particles for applications including, polymer seals, battery, pesticide, food ingredients, cellulose products, elastomer, and water treatment. Over the next five years, we will focus on the following objectives:
Objective 1: Enable commercial production of new products based on functionalized particles for polymer seals and energy storage applications.
Objective 2: Enable commercial production of new products based on the microencapsulation of environmentally-friendly pesticides and bioactive food ingredients.
Objective 3: Enable commercial production of value-added products of micro/nano-sized celluloses and hemicelluloses from various agricultural wastes.
Objective 4: Enable commercial processes to produce biochar products for elastomer composites and water treatment applications.
Approach
This research aims to enable biobased particle technologies that produce functional particles using renewable agricultural byproducts and feedstocks. The characteristics of these functional particles include size, shape, aggregate structure, and surface functionalities. These particles can be further modified to function as reinforcements in polymer matrices, multifunctional coatings for battery separator membranes, as controlled-release materials delivering food ingredients and chemicals and as cosmetic ingredients, and filtering media for water purification. The outcome of this research will contribute to the utilization of vast amounts of byproducts generated by the food industries, and benefit climate change by reducing greenhouse gases, all of which will promote a sustainable global bio-economy. Our previous research on biobased particles has produced composites with useful mechanical properties. Further development will advance polymer seals and energy storage applications. Our ‘masterbatch process’ will be applied to develop multifunctional coatings on battery separator membrane for ion conduction and short circuit prevention. Encapsulated products will be developed to extend active time of natural pesticides and to stabilize bioactive food ingredients. We will also develop nano-size hemicellulose/cellulosic materials for composite and cosmetic applications. Sustainable biochar from agricultural byproducts will be developed as an effective water filtration media for agricultural run-off and potable water. We will also improve biochar to become a more effective rubber filler. Upon the completion of this project plan, all technologies developed will be transferred to respective industries.
Progress Report
For objective 1, significant progress was made on the preparation and evaluation of polymer seals with soy-derived particles. One of the many applications for rubber is as rubber seals, such as O-rings, cup gasket, bellows diaphragms, sealing/wiper lips, and many others. The current rubber seals in the market do not contain renewable agricultural materials. To expand the market for agricultural materials and increase their value, we have attempted to incorporate these materials in rubber seal products. Among the requirements for rubber seals is good oil resistance so that the seals can maintain their mechanical properties in oily environment; however, not all rubbers have acceptable oil resistance when used in various applications. To improve oil resistance of rubbers by using renewable materials, three rubbers that have poor oil resistance were chosen as targets for improvement. Soybean-derived protein particles were used as filler at 40-60% to reinforce these rubbers. ARS researchers at Peoria, Illinois, found that the rubbers reinforced with soy protein particles had less swelling in oil and their strength was more stable with temperature change when compared with carbon black reinforced rubbers. The results indicate that the approach used is a promising route to further improve physical properties of rubber seals.
For Objective 2, significant progress was made on the preparation of protein microparticles that carry biopesticides. Encapsulation of pesticides into biodegradable polymers is a recent technology that enables pesticides to remain effective for a longer time following application. Corn protein (zein) was used as a shell material because of its well-established functionality as an encapsulant and then identified several controlling factors that lead to the highest encapsulation efficiency. This year, for the evaluation of the effect of encapsulation (i.e., controlled release of pesticides), we investigated the release profile of encapsulated pesticides and developed our own lab equipment for this work, as no commercial equipment is available for the continuous monitoring of the release profile. The obtained data clearly demonstrated that the encapsulation delays the evaporation of chemicals. This delay in evaporation varies depending on the encapsulation conditions. As zein is expensive, we isolated and purified another protein (gliadin, a wheat protein) that will replace zein. It's been noted that the functionality of gliadin as an encapsulant is promising. These findings will help scientists who use encapsulation technology when developing controlled-release chemicals.
For Objective 3, significant progress was made on the preparation of micro-/nano- cellulose and hemicellulose from agricultural wastes. Agricultural waste such as sorghum stover has little value. However, value-added products such as hemicellulose and cellulose can be prepared from sorghum stover. Three preparation methods have been investigated and compared to obtain the hemicellulose. One method was to use hot water to extract hemicellulose from sorghum stover at three solvent temperatures (80-100 C). Another method was to use sodium hydroxide at three different concentrations (4% - 10%). The last method was to use ethanol and strong base to remove the lignin from sorghum stover first, and then the hemicellulose was extracted with a dilute sodium hydroxide solution. The properties of the hemicellulose were investigated using infrared spectroscopy, liquid chromatography, and rheometer. The results show that sorghum stover hemicellulose, when prepared further into gels, can absorb significant amount of water. The ability of absorbing water indicates it can be used as a component in cosmetics to retain moisture in products such as face creams.
For Objective 4, significant progress was made on optimizing nanoparticle milling methods for biochar composites. Carbon black, the dominant filler in the global tire industry, is sourced from petroleum and contributes towards global warming. However, renewable sources of carbon reduce petroleum dependence while helping the environment. Biochar is a renewable source of carbon made from biomass that can replace carbon black in rubber composites. ARS researchers have discovered a synergistic effect between calcium carbonate and soy protein that helps reinforce rubber composites. By combining calcium carbonate, soy protein, and biochar in a new milling technique, rubber composites were created that allow up to 50% replacement of carbon black with virtually no loss in strength and with increased elongation and toughness. Rubber composites such as these have similar properties as their carbon black analogs but are more sustainable and reduce dependence on petroleum.
Accomplishments
1. Improved oil resistance of rubber containing agricultural filler for seal applications. Some common rubbers have poor oil resistance, which is a disadvantage for rubber seals in many applications. ARS researchers at Peoria, Illinois, have studied the effect of an agricultural filler (from soy protein) in rubber composition on the oil resistance of the reinforced rubber. They found that rubber reinforced with soy protein particles has less swelling in oil and the mechanical strength does not decrease significantly as the temperature is increased when compared to carbon black reinforced rubber. The development of a new soy protein-reinforced rubber product for rubber gasket applications has the potential to increase the market and value of the soybean crop and soy protein, creating new economic opportunities for farmers and rural communities.
2. Encapsulation of natural biopesticides into protein nanocapsules. Many essential oils are natural biopesticides that are environmentally friendly. However, essential oils evaporate quickly, so their active times as pesticide are short. To resolve this issue, ARS researchers at Peoria, Illinois, encapsulated the major component of an essential oil (menthol, as a model system) into a shell comprised of a corn protein, and developed an optimized encapsulation process that leads to the highest possible encapsulation efficiency. The established encapsulation procedure can be applied with minor modifications to various essential oils and other volatile natural biopesticides to increase their active times. In the case of eucalyptus oil, the active time was increased three to four times.
3. Development of value-added hemicellulose from agricultural waste sorghum stover. Sorghum stover is normally categorized as waste because it has very little economic value. At present, most sorghum stover is mulched back into the soil or burned as fuel. Sorghum contains hemicellulose, a polysaccharide present with cellulose in almost all terrestrial plant cell walls. ARS researchers at Peoria, Illinois, developed an optimized method for the inexpensive and relatively “green” production of value-added hemicellulose from sorghum stover. Hemicellulose has many applications such as package films, emulsifiers, stabilizers, gels, and binders in food products, and can be further cross-linked into hydrogels that can be used in cosmetic products, agricultural seed coatings, and wound healing materials. This work on a biobased renewable resource benefits the environment and could generate additional income for sorghum growers.
Review Publications
Jong, L. 2020. Synergistic effect of calcium carbonate and biobased particles for rubber reinforcement and comparison to silica reinforced rubber. Journal of Composites Science. 4(3). Article 113. https://doi.org/10.3390/jcs4030113.
Cheng, H.N., Biswas, A., Kim, S., Alves, C.R., Furtado, R.F. 2021. Synthesis and characterization of hydrophobically modified xylans. Polymers. 13:291. https://doi.org/10.3390/polym13020291.
Liu, S.X., Chen, D., Plumier, B.M., Berhow, M.A., Xu, J., Byars, J.A. 2020. Impact of particle size fractions on composition, antioxidant activities, and functional properties of soybean hulls. Journal of Food Measurement and Characterization. 15:1547-1562. https://doi.org/10.1007/s11694-020-00746-0.
Peterson, S.C., Kim, S., Adkins, J.E. 2021. Surface Charge Effects on Adsorption of Solutes by Poplar and Elm Biochars. C - Journal of Carbon Research. 7(1). Article 11. https://doi.org/10.3390/c7010011.
Jackson, M.A., Price, N.P., Blackburn, J.A., Peterson, S.C., Kenar, J.A., Haasch, R., Chen, C. 2019. Partial hydrodeoxygenation of corn cob hydrolysate over palladium catalysts to produce 1-hydroxy-2-pentanone. Applied Catalysis A: General. 577:52-61. https://doi.org/10.1016/j.apcata.2019.03.019.
Kim, S., Peterson, S.C. 2021. Optimal conditions for the encapsulation of menthol into zein nanoparticles. LWT - Food Science and Technology. 144:Article 111213. https://doi.org/10.1016/j.lwt.2021.111213.
Moser, B.R., Doll, K.M., Peterson, S.C. 2019. Renewable poly(thioether-ester)s from fatty acid derivatives via thiol-ene photopolymerization. Journal of the American Oil Chemists' Society. 96(7):825-837. https://doi.org/10.1002/aocs.12244.
Vaughn, S.F., Moser, J.K., Berhow, M.A., Byars, J.A., Liu, S.X., Jackson, M.A., Peterson, S.C., Eller, F.J. 2020. An odor-reducing, low dust-forming, clumping cat litter produced from Eastern red cedar (Juniperus virginiana L.) wood fibers and biochar. Industrial Crops and Products. 147. Article 112224. https://doi.org/10.1016/j.indcrop.2020.112224.
Vaughn, S.F., Byars, J.A., Jackson, M.A., Peterson, S.C., Eller, F.J. 2021. Tomato seed germination and transplant growth in a commercial potting substrate amended with nutrient-preconditioned Eastern red cedar (Juniperus virginiana L.) wood biochar. Scientia Horticulturae. 280. Article 109947. https://doi.org/10.1016/j.scienta.2021.109947.
Vaughn, S.F., Theiling, C., Rosenbohm, P., Eller, F.J., Peterson, S.C. 2021. Evaluation of engineered soils for bioretention areas containing dredged Illinois River sand, compost, biosolids and pyrolyzed biosolids. Crop, Forage & Turfgrass Management. 7(1). Article e20096. https://doi.org/10.1002/cft2.20096.
