Location: Plant Polymer Research
2024 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
A critical vacancy has halted progress of Objective 1. In support of Objective 2, research has progressed as planned. The corn protein, zein, is the most common encapsulant for many types of core materials, including fragrances, drugs, nutraceuticals, and pesticides. With conventional encapsulation technology, the core materials must dissolve in 90% ethanol. Therefore, highly hydrophobic compounds that do not dissolve in this solvent, such as long-chain fatty acids and many bio-active food ingredients, cannot be encapsulated with zein. To resolve this issue, ARS researchers in Peoria, Illinois, developed a new encapsulation process by modifying the conventional process. With this new process, the difficulty of dissolving the starting material was resolved by using multiple solvents. This new process allows encapsulation of most water-insoluble core materials, such as fragrances, drugs, nutraceuticals, and pesticides, into zein capsules.
For the controlled release and/or environmental protection of core materials, such as bioactive essential oils and healthy polyunsaturated fats, zein encapsulation has been utilized. However, the application of the conventional encapsulation process is limited to water-insoluble core materials. To resolve this issue, a protocol for the encapsulation of water-soluble compounds was developed. With this protocol, a water-soluble biopolymer is used as a base material and mixed with a target core material and freeze-dried to prepare solid particles. These particles are then coated with zein. In principle, any type of water-soluble core material, such as certain vaccines, can be encapsulated into zein capsules using this process. Encapsulation of vaccines is particularly useful for oral administration of animal vaccines because the shell can protect the vaccine from degradation in the gut.
In support of Objective 3, three different preparation methods have been investigated, compared, and optimized to prepare cellulose from soybean hulls, a plentiful agricultural waste material. ARS researchers in Peoria, Illinois, determined various conditions of the extraction process such as pH, temperature, and heating time. Three separate mechanical shearing methods (homogenization, micro-fluidization, and jet-cooking) were also compared and optimized to determine the most efficient means of nanocellulose production. Characterization of the soybean hull-based nanocellulose is ongoing and involves determining chemical purity, morphological studies by low-voltage electron microscope, mechanical properties of nanocellulose thin films, and viscoelastic properties of nanocellulose gels.
In support of Objective 4, biochars, sourced from pistachio shells and walnut shells, were evaluated as a potential rubber composite filler. Walnut and pistachio shells are a plentiful, low-value agricultural waste stream. By heat- treating these shells in the absence of oxygen, they can be converted to biochar, a sustainable source of carbon that is like carbon black, a common rubber composite filler that is sourced from fossil fuels. ARS researchers in Peoria, Illinois, have formulated rubber composites where up to 40% of the carbon black has been replaced with walnut or pistachio shell biochar, and yet still has improved tensile strength, elongational properties, and toughness relative to a 100% carbon black-filled control.
Accomplishments
1. Development of high-value nanocellulose fibers from waste soybean hulls for cosmetic, pharmaceutical, and medical products. Soybean hulls are an agricultural waste product that has little value. Millions of bushels of soybean hulls are produced each year in the United States. ARS researchers in Peoria, Illinois, have developed a method to prepare nanocellulose from soybean hulls. Nanocellulose fibers are tiny, plant-based fibers that are incredibly strong, environmentally friendly, sustainable, and non-toxic (safe for food and medical uses). Because of their very small size and unique properties, nanocellulose fibers are high-value, biodegradable materials that are useful in the production of cosmetics, drug delivery systems, and wound-healing applications. These results advance the conversion of a high-volume agricultural byproduct into valuable biobased materials promoting economic opportunities for soybean farmers and sustainable options for industry and consumers.
2. Using walnut and pistachio shells to reduce fossil fuel dependence. Pistachio and walnut shells are low-value agricultural waste materials. These shells can be processed into biochar, a sustainable form of solid carbon that is like carbon black, a common rubber composite filler sourced from fossil fuels. ARS researchers in Peoria, Illinois, have developed natural rubber composites where up to 40% of the carbon black has been replaced with pistachio or walnut shell biochar that provides improved tensile strength, elongation, and toughness properties relative to a 100% carbon black-filled control. Thus, this technology enables the conversion an agricultural waste stream into a renewable filler for rubber capable of replacing a large portion of a fossil fuel-derived filler, namely, carbon black. This development promotes new economic opportunities for pistachio and walnut producers as well as rubber compound producers and users and helps reduce our dependence on fossil resources.
Review Publications
Peterson, S.C., McMahan, C.M. 2023. Replacement of carbon black with coppiced biochar in guayule rubber composites improves tensile properties. Journal of Composites Science. 7(12):499. https://doi.org/10.3390/jcs7120499.
Hwang, H., Kim, S., Moser, J.K. 2024. Unsaturation and polar compounds of vegetable oils affect the properties of sunflower wax oleogels. European Journal of Lipid Science and Technology. https://doi.org/10.1002/ejlt.202300205.
Cheng, H.N., Biswas, A., Kuzniar, G., Kim, S., Liu, Z., He, Z. 2024. Blends of carboxymethyl cellulose and cottonseed protein as biodegradable films. Polymers. 16(11). Article 1554. https://doi.org/10.3390/polym16111554.
Xu, J., Boddu, V.M., Kenar, J.A. 2024. Micro-heterogeneity and micro-rheological properties of cellulose-based hydrogel studied by diffusing wave spectroscopy (DWS). Cellulose Chemistry and Technology. 58(1-2), 1-7. https://doi.org/10.35812/CelluloseChemTechnol.2024.58.01.
Xu, J., Kenar, J.A. 2024. Rheological and micro-rheological properties of chicory inulin gels. Gels. 10(3). Article 171. https://doi.org/10.3390/gels10030171.
Selling, G.W., Hay, W.T., Peterson, S.C., Hojilla-Evangelista, M.P., Kenar, J.A., Utt, K.D. 2024. Structure and functionality of surface-active amylose-fatty amine salt inclusion complexes. Carbohydrate Polymers. https://doi.org/10.1016/j.carbpol.2024.122186.
