Location: Plant Polymer Research
2019 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 elastomer, coating, agricultural, medical, and cosmetic applications. Over the next 5 years, we will focus on the following objectives:
Objective 1: Enable the commercial production of new products based on functionalized particles for applications in elastomeric composites and latex coatings.
Objective 2: Enable new commercial processes to produce marketable biochar particles for rubber composite filler applications.
Objective 3: Enable the commercial production of new products based on nano- or micro-particles for controlled-release of chemicals.
Objective 4: Enable the commercial production of new products based on biodegradable nanoparticles from starch, and expand their end-use applications.
Objective 5: Enable the commercial production of new products based on micro-and nano-sized particles of lignin and cellulose.
Approach
The aim of this research is to develop biobased particle technologies that produce functional particles using renewable agricultural byproducts and feedstocks. The characteristics of the functional particles include size, shape, aggregate structure, and surface functionalities that can be changed for the particles to function as reinforcements in polymer matrices, hydrocolloids for modifying rheological and surface properties, and controlled-release vehicles for delivering chemicals. The outcome of this research will contribute to the utilization of voluminous byproducts generated by the biofuel and food industries, reduction of greenhouse gases responsible for climate change from carbon black production, and sustainability of the global economy. Currently, carbon black is the dominant filler in rubber products. Our previous research on biobased particles has produced natural rubber composites with useful mechanical properties. Further development will be on the regulation of particle connectivity and interface adhesion. Our masterbatch process will be extended to the rheology and films of latex coatings. Carbonized biomaterials as feedstock will also be developed as rubber filler with emphasis on the methods of biochar production to address performance, quality, and supply issues. We have produced nanoparticles of amylose complexes with steam jet cooking technology and will improve particle functionality for composite, coating, and medical applications. We will also develop nano-size cellulose/lignin for composite and cosmetic applications. For controlled-release applications using biobased particles, the functional particles to deliver chemicals, specifically pesticides, will be developed to solve wash-away issues and reduce pesticide consumption. The resulting technologies will be transferred to users who use these products.
Progress Report
For Fiscal Year 2019, we have met all our milestones. Our accomplishments and progress are documented in peer-reviewed scientific publications, a patent application, and a material transfer agreement.
Latex paint for interior architectural coating is a widely used commercial product. The flowing properties of such paint are important and must be adjusted in the formulation with a thickener to change its viscosity and flow properties. For better performance, the viscosity of the paint should be low when brushing/rolling to produce a thin coating, while the viscosity should be suitably high so it will not sag when the paint is on a wall. In the current development, the insoluble soy carbohydrate waste is modified after soy protein has been extracted from defatted soy flour. The modified soy carbohydrate is found to increase the viscosity and change the flowing behavior of latex paint and is also found to have better performance compared to commercial thickeners based on modified cellulose.
Our research effort is to make rubber composites for the tire industry that replace carbon black filler (fossil-fuel based) with biochar (from renewable biomass) as much as possible without detrimental effects in the final composite. In past milestones, we have focused on styrene-butadiene rubber (SBR) as the rubber matrix. With this milestone, we have applied our biochar improvement methods learned in previous years and formulated composites using natural rubber as the matrix, thus demonstrating and expanding market potential of biochar-filled rubber composites.
The problem with existing insecticides is that they can be washed away by rain or morning dew after application. This situation requires repeated application of the insecticide to annihilate the targeted insects. To resolve this issue, ARS scientists in Peoria, Illinois, have developed a procedure to encapsulate insecticides into tiny particles that adhere on the surface of plant leaves and remain there until the insects consume them. A provisional patent for this technology was filed last year. For commercial viability, the production procedure was improved by using non-toxic chemicals and low-cost materials. The performance of the products produced with an improved process was proven to be excellent. Application for an international patent is in progress.
Intimate mixtures of high amylose starch and oleic acid in ethanol were prepared and the ethanol was evaporated at room temperature. The starch-oleic acid mixtures were then cooked at high temperature and pressure, and the resulting solutions were instantly cooled to 0 deg. C. Smaller crystals were obtained by rapid cooling, and the average size of the crystals obtained by this procedure was 300 nanometers. The aqueous dispersions of crystals were blended with a rubber latex. Films prepared with 25-60% of crystals in rubber were neither soft and sticky or brittle, and these films had tensile strengths and elongations that indicated a potential for commercial applications. Although the tensile properties of films cast from the rubber latex could also be varied by varying the ratios of components in the rubber latex, the advantage of varying film properties by using different amounts of the biodegradable crystals is that the presence of starch in the films will enhance their biodegradability when they are disposed of in landfills.
Three high shearing methods were used to reduce the particle size of lignin. The particle sizes were measured with an optical microscope and a scanning electron microscope. The untreated commercial lignin particle sizes are several tens of microns. After high mechanical shearing, the sizes of the lignin particles were reduced to several microns. The preparation method of plastic-like composites made with commercial lignin and micro-sized-lignin were developed. Two biodegradable polymers, polyvinyl alcohol and polycaprolactone, together with lactic acid and lignin, were investigated for the preparation of lignin-based composites. The different ratio of polyvinyl alcohol:lignin or polycaprolactone:lignin was evaluated. The optimum lignin-based composite can be made with 20-30% polyvinyl alcohol, 10% lactic acid, and 60-70% lignin or micro-sized-lignin. Several molding methods have been studied and evaluated. The mechanical properties of lignin plastic-like materials are currently under investigation.
Our research contributes to the national economy by creating new applications and potential markets for agricultural materials.
Accomplishments
1. Improve the flowing performance of latex paint with modified soy carbohydrate. Flowing properties are important in the application of latex paint. The paint should have low viscosity when brushing /rolling to provide a thin coat, but high viscosity when on a wall to prevent sagging. ARS scientists in Peoria, Illinois, have developed a better thickener from modified soy carbohydrate that produces low viscosity during brushing/rolling and high viscosity on a wall compared to modified cellulose thickener commonly used in latex paint. This development will increase the value of soy carbohydrate, which is currently a waste product from the extraction of soy protein from soybean and provide a better product for latex paint applications.
2. Formulation of natural rubber composites with 50% replacement of carbon black with biochar. Natural rubber composites are widespread in the tire and automotive industries. Up to this point, we have focused solely on utilizing biochar as filler in styrene-butadiene rubber, and our work demonstrates that our technology for replacing carbon black with biochar is also applicable to natural rubber composites as well. ARS scientists in Peoria, Illinois, have developed natural rubber composites that substitute 50% of the carbon black filler with renewable biochar. These composites retain 95% of the tensile strength of a 100% carbon black-filled control, while having improved elongation and toughness properties. This technology expands the market of biochar-filled rubber composites. Carbon black is a non-renewable, fossil-fuel based commodity that has an enormous market in the tire industry (roughly 1.2 million metric tons in 2015), so even partially replacing this fossil fuel-based commodity with renewable biochar would have a significant impact in reducing climate change and reducing our dependence on petroleum.
3. Optimum conditions for the encapsulation of essential oils into protein microcapsules. Certain essential oils are used as a natural pesticide for pests, specifically insects and select arthropods. Because essential oils are volatile, encapsulation into micrometer-scale particles that are comprised of protein is needed to retard their evaporation and increase their effective time. Although zein has long been utilized to prepare microcapsules, systematic investigation to understand the optimum conditions to produce microcapsules has not been conducted. ARS scientists in Peoria, Illinois, have investigated the mechanism for this encapsulation process and identified the major controlling factors that govern the encapsulation efficiency. As a result, it was demonstrated that the encapsulation efficiency can exceed 90% by producing micro-particles at optimum conditions. This development will help farmers reduce costs and increase the efficiency and safety of applying insecticides to crops.
4. Mechanical properties of rubber reinforced with starch and fatty acid complexes. Non-biodegradable polymer film is an environmental issue. To improve the biodegradability of polymer film, ARS scientists in Peoria, Illinois, have developed nano-sized particles of starch-oleic acid inclusion complexes using steam jet cooking mixtures of high amylose corn starch and oleic acid and then rapidly cooling the jet cooked dispersions with ice. Films with good tensile properties were prepared from mixtures of these nanoparticles with styrene-butadiene rubber latex. The advantage of such films containing starch-oleic acid nanoparticles is that the presence of starch in the films will enhance their biodegradability and improve our environment.
5. Investigate micro-scale dispersion properties of soluble glutinous rice starch using diffusing wave spectroscopy. As a natural biopolymer, soluble glutinous rice starch is widely used in the food industry. However, the properties and structure-function relationship of rice starch are still not clearly understood. Diffusing wave spectroscopy (DWS) is a novel technology that can probe micro-scale dispersion properties of polymers over a wider range of scale than similar instruments. It monitors the thermal-driven motion of micro-beads that are embedded in a polymer sample without disturbing the sample and gains the insight of the sample properties. ARS scientists in Peoria, Illinois, have studied micro-scale dispersion properties of rice starch using DWS. We observed relatively rapid concentration-induced transitions of the micro-scale dispersion properties of rice starch solutions. This work revealed new insight into the physical properties of rice starch solutions, and the results of this work will be useful in creating new applications of rice starch solutions in drug delivery and wound healing to increase the utilization of this agricultural material and benefit the farming economy.
Review Publications
Jong, L. 2019. Particle reinforced composites from acrylamide modified blend of styrene-butadiene and natural rubber. Polymer Composites. 40(2):758-765. https://doi.org/10.1002/pc.24734.
Evans, K.O., Compton, D.L., Kim, S., Appell, M.D. 2019. Charged phospholipid effects on AAPH oxidation assay as determined using liposomes. Chemistry and Physics of Lipids. 220:49-56. https://doi.org/10.1016/j.chemphyslip.2019.02.004.
Gómez, A.V., Tadini, C.C., Biswas, A., Buttrum, M., Kim, S., Boddu, V.M., Cheng, H.N. 2019. Microwave-assisted extraction of soluble sugars from banana puree with natural deep eutectic solvents (NADES). LWT - Food Science and Technology. 107:79-88. https://doi.org/10.1016/j.lwt.2019.02.052.
Biswas, A., Cheng, H.N., Kim, S., Appell, M.D., Boddu, V.M., Alves, C.R., Furtado, R.F. 2019. Preparation of sorbitol-based polyurethanes and their semiinterpenetrating polymer networks. Journal of Applied Polymer Science. 136:47602. https://doi.org/10.1002/app.47602.
Biswas, A., Kim, S., Buttrum, M.A., Furtado, R.F., Alves, C.R., Cheng, H.N. 2018. Preparation of hydrophobically modified Cashew Gum through reaction with Alkyl Ketene Dimer. Green Polymer Chemistry: New Products, Processes, and Applications. ACS Symposium Series. 1310:137-146.
Biswas, A., Kim, S., Furtado, R.F., Alves, C.R., Buttrum, M., Boddu, V.M., Cheng, H.N. 2018. Metal chloride-catalyzed acetylation of starch: Synthesis and characterization. International Journal of Polymer Analysis and Characterization. 23(6):577-589.
Liu, S., Chen, D., Xu, J. 2019. Characterization of amaranth and bean flour blends and the impact on quality of gluten-free breads. Journal of Food Measurement and Characterization. 13(2):1440-1450. https://doi.org/10.1007/s11694-019-00060-4.
Hay, W.T., Fanta, G.F., Felker, F.C., Peterson, S.C., Skory, C.D., Hojilla-Evangelista, M.P., Biresaw, G., Selling, G.W. 2019. Emulsification properties of amylose-fatty sodium salt inclusion complexes. Food Hydrocolloids. 90:490-499. https://doi.org/10.1016/j.foodhyd.2018.12.038.
Xu, J., Liu, W-C., Boddu, V.M. 2018. Viscoelastic properties of microfibrillated cellulose (MFC) produced from corn stover. Cellulose Chemistry and Technology. 52(5-6):337-342.
Felker, F.C., Fanta, G.F., Peterson, S.C. 2019. Glucose-reduced silver nanoparticles prepared with amylose-sodium palmitate inclusion complexes and their dry storage and reconstitution. Starch. https://doi.org/10.1002/star.201800238.
