Location: Plant Polymer Research
2017 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 FY17, we have met our planned milestones to develop modified rubber composites with soy nanoparticles, charcoal particulates from Paulownia and poplar wood, encapsulation of spinosad molecules, particles of starch-fatty amine complexes, and micro-/nano-cellulose particles from soybean stover for a variety of industrial elastomer, plastic, and coating applications. Our accomplishments and progress are documented in peer-reviewed scientific publications, invention disclosures, material transfer agreements and material transfer research agreements.
Rubber products require reinforcing filler materials, which are currently dominated by carbon black that is produced by burning heavy oil with the generation of harmful emissions. Renewable fillers from agriculturally-derived particles can be used to increase mechanical strength of rubbers for various applications such as rubber cushion, sound insulation, and automobile tires. The strength of the rubber can be further increased by making it more compatible with biobased particles. A single step process was developed to incorporate a hydrophilic molecule to a blend of a synthetic and natural rubber to make them more compatible with soy protein nanoparticles. Soy protein nanoparticles were prepared by breaking up soy protein aggregates with different types of chemicals and processed at different temperatures for a certain duration. They were further processed with different shearing force to further break up the larger particles into nano-sized particles. The mechanical properties including strength, stiffness, and toughness were measured. The results indicate the strength of the rubber composites were improved substantially, especially when the rubber is highly stretched. These results show that they have potential to be used in a variety of molded rubber objects for damping applications.
Our research objective 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 on the final composite. To do this, we worked with a collaborator to procure potential wood feedstocks that would be successful in producing biochar to meet industry criteria. Two feedstocks that are plentiful due to their rapid growth rate and wide geographical footprint across the United States were selected. Biochars made from these feedstocks are co-milled with commercial ingredients, can replace 30-40% of the carbon black in a styrene-butadiene rubber composite and increase the elongation and toughness with minimal loss of tensile strength compared to the 100% carbon black control. This is doubling the amount of replaceable carbon black from our previous research. There is great potential to use co-milled biochar in not only tire applications but other composite applications that require the combination of elongation and strength.
Excessive use of synthetic pesticides has resulted in an increased risk of pesticide resistance, enhanced pest resurgence, toxicological implications to human health, and increased environmental pollution. To mitigate these problems, natural pesticides emerged as an alternative to the existing synthetic chemicals. Bio-pesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. These pesticides generally affect only the target pest and closely related organisms. Spinosad is a bio-pesticide that can be used on lawns, vegetables, and fruit trees, to control caterpillars, thrips, leaf miners, borers, fruit flies, spider mites, and aphids. Pesticides wash away with rain. To avoid repeated applications, encapsulation of spinosad molecules was accomplished. The encapsulated spinosad stays on the surface of leaves intact until it is ingested by the insects. The performance of encapsulated spinosad was evaluated by using three different caterpillar pests of several crops, cabbage loopers, corn earworms and fall armyworms. As the encapsulated material showed excellent performance on both washed (i.e., imitation of rainfall) and non-washed cabbage leaves treated with the encapsulated spinosad, an invention disclosure was filed based on this product and the results.
Films prepared from mixtures of polyvinyl alcohol (PVOH) and the water soluble starch complexes prepared from the salts of fatty amines had higher values for percent elongation than films that were prepared from pure PVOH or from mixtures of PVOH and similar starch complexes prepared from the salts of fatty acids. The resistance of these films to the penetration of water, as shown by the contact angles of water droplets, was also greater than films prepared from pure PVOH. Microscopy of the films showed no phase separation of PVOH and amylose complex. This is consistent with an intimate mixture of the two film components, possibly due to ionic association between the cationic ammonium groups of the amylose salt complexes and the hydroxyl groups of PVOH. The high percent elongations of these films suggest that they could have a marketable advantage in some areas of application. These films are more biodegradable than films prepared from pure PVOH, since they contain a high percentage of starch-based complexes. In a second area of research, an US patent has been filed on the application of water solutions of amylose fatty amine salt complexes to paper to make the paper more resistant to the penetration of water. Positive charges on the water soluble amylose amine salt complexes causes the complexes to adhere to the negatively charged hydroxyl groups of the cellulose fibers of the paper. A second treatment with a solution of sodium hydroxide converts the fatty amine salt in the amylose complex to the corresponding water insoluble amine causing the complex to precipitate onto the cellulose fibers, making the paper more water resistant.
A method of preparation of micro-/nano cellulose from soybean stover was developed. The condition of the extraction such as acidity/basicity (pH), temperature, and heating time were determined. The temperature, pressure, and passing time of mechanical shearing using homogenizer were optimized. The study of the form, size, and structure of the micro-/nano cellulose has been conducted using transmission electron microscopy. The rheological properties of nano-sized cellulose gels produced from corn stover were characterized. The viscoelastic (material behavior between solid and liquid) properties of the nano-cellulose gels at different concentrations were investigated. The nano-cellulose gels exhibited concentration-dependent, solid-like properties. Higher nano-cellulose concentrations resulted in stronger properties. The analysis for different concentrations of the nano-cellulose gels indicated that they were physical gels, meaning the cross-linkers between the molecules exhibited physical interactions. The mechanical shearing studies implied that the nano-cellulose gels from corn stover exhibited shear thinning behavior (viscosities decreased with increasing shearing rate), which can be well described by a mathematical model.
Our research contributes to the national economy by creating new applications and potential markets for agriculture materials.
Accomplishments
1. Improved rubber blends with biobased nanoparticles from soybeans. In order to have good mechanical strength in rubber products for a variety of uses, small particles are used in most rubber products to make them stronger. The most common particles used in rubber are carbon black derived from petroleum by-products. Agricultural Research Service scientists in Peoria, Illinois, have produced useful rubber composites reinforced with soy-based nanoparticles by attaching a hydrophilic molecule to a blend of synthetic and natural rubber so that the mechanical strength of the rubber composite is significantly increased. This development will increase the use and value of soybean products, and improve functionality of the rubber products.
2. Identification of viable woody biochar feedstocks for carbon black substitution as rubber composite filler. The price of petroleum and its byproducts (such as carbon black) are projected to rise over time as demand increases, especially in rapidly growing markets like China and India. Biochar is a solid, granular, carbon-containing material made from renewable biomass that can substitute carbon-black applications. Agricultural Research Service scientists in Peoria, Illinois, have tested and confirmed a process for making biochar from two hardwood sources that contains at least 95% carbon and less than 3% ash. The feedstocks are plentiful due to their popularity as biomass energy crops, which is a result of their rapid growth rate. Biochar with that level of carbon purity has been successful in replacing up to 30% of the carbon black filler in rubber composites that can stretch and absorb energy without breaking just as well or better than the carbon black control. With the sheer size of the carbon black market (roughly 1.2 million metric tons in 2015), even partially replacing this fossil fuel-based commodity with renewable biochar would have a significant impact in reducing our dependence on petroleum.
3. Encapsulation of natural pesticides. Biopesticides provide an alternative to the use of chemical insecticides; however, biopesticide efficacy is affected by climatic conditions, especially rain that washes away the products. Agricultural Research Service scientists in Peoria, Illinois, have encapsulated spinosad (as a model pesticide) in tiny particles that adsorb on the surface of leaves, reducing wash-off by rain or morning dew and increasing exposure to insects, thus reducing application of pesticides as well as envionmental contamination. This encapsulation technique can be extended to other pesticides and possibly herbicides and fungicides.
4. Starch-containing polyvinyl alcohol (PVOH) films with improved properties. Although films prepared from PVOH are widely used and have excellent elongation properties, PVOH biodegrades slowly, creating a need for high quality films prepared from mixtures of PVOH and inexpensive, rapidly-biodegradable components. Agricultural Research Service scientists in Peoria, Illinois, have prepared films with marketable properties from mixtures of PVOH and starch complexes prepared from fatty ammonium salts. This research will enable manufacturers to prepare films that are more environmentally friendly due to the starch component that biodegrades rapidly and completely.
5. Increased water resistance of paper. Paper absorbs water rapidly, and numerous chemical treatments have been used to reduce water absorption. However, most of the chemicals used for this purpose are toxic and non-biodegradable. Agricultural Research Service scientists in Peoria, Illinois, have filed an US patent on a new method for preparing water resistant paper using starch and fatty ammonium salt complexes. These complexes can potentially replace other petroleum based water resistant coatings. These complexes are non-toxic and are prepared from biodegradable starch, compared to other similar coating products made from petroleum feedstocks and contain toxic components.
6. Investigation of nano-sized cellulose from agricultural waste - corn stover. Many agricultural residues including corn stover, soybean stover, sorghum stover, corn fiber, rice hulls, wheat straw, rice straw, and pennycress weed have little economic value other than for burning as fuel. Little research has been conducted into using these agricultural wastes for higher value polymer material applications. Agricultural Research Service scientists in Peoria, Illinois, developed a method to prepare a nano-sized cellulose from corn stover for the first time. The rheological property study for this product indicated that the function and behavior of the corn stover nano-cellulose can be a candidate for applications in cosmetic gels and wound skin care materials after compared to corn stover nano-cellulose properties with some cosmetic gels and wound skin care material properties. The micro- and nano-sized celluloses can be widely used in cosmetics, wound-healing, drug delivery, and reinforcement of composites. This work provided a path to develop new value-added materials from agricultureal wastes.
Review Publications
Jong, L., Liu, Z. 2017. Biobased composites from cross-linked soybean oil and thermoplastic polyurethane. Polymer Engineering & Science. 57(3):275-282.
Hay, W.T., Behle, R.W., Fanta, G.F., Felker, F.C., Peterson, S.C., Selling, G.W. 2016. Effect of spray drying on the properties of amylose-hexadecylammonium chloride inclusion complexes. Carbohydrate Polymers. 157:1050-1056. doi: 10.1016/j.carbpol.2016.10.068.
Fanta, G.F., Felker, F.C., Hay, W.T., Selling, G.W. 2017. Increased water resistance of paper treated with amylose-fatty ammonium salt inclusion complexes. Industrial Crops and Products. 105:231-237.
Liu, S.X., Chen, D., Inglett, G.E., Xu, J. 2017. The effect of thermo-mechanical processing on physical properties of processed amaranth and oat bran composites. Journal of Food Research. 6(2):82-91.
Vaughn, S.F., Kenar, J.A., Tisserat, B., Jackson, M.A., Joshee, N., Vaidya, B.N., Peterson, S.C. 2017. Chemical and physical properties of Paulownia elongata biochar modified with oxidants for horticultural applications. Industrial Crops and Products. 97:260-267.
Finkenstadt, V.L., Kenar, J.A., Fanta, G.F. 2016. Corrosion protection of steel by thin coatings of starch-oil dry lubricants. In: Sharma, B.K., Biresaw, G., editors. Environmentally Friendly and Biobased Lubricants. Boca Raton, FL: CRC Press. p. 407-417.
Jong, L. 2017. Reinforcement effect of soy protein nanoparticles in amine-modified natural rubber latex. Industrial Crops and Products. 105:53-62.
Hay, W.T., Fanta, G.F., Byars, J.A., Selling, G.W. 2017. Rheological characterization of solutions and thin films made from amylose-hexadecylammonium chloride inclusion complexes and polyvinyl alcohol. Carbohydrate Polymers. 161:140-148.
Kim, S. 2016. A protocol for the production of gliadin-cyanoacrylate nanoparticles for hydrophilic coating. Journal of Visualized Experiments. doi:10.3791/54147.
Xu, J., Inglett, G.E., Liu, S.X., Boddu, V.M. 2016. Micro-heterogeneity and micro-rheological properties of high-viscosity barley beta-glucan solutions studied by diffusion wave spectroscopy (DWS). Food Biophysics. 11(4):339-344.
Kim, S., Adkins, J.E., Biswas, A. 2017. Reinforcement of latex rubber by the incorporation of amphiphilic particles. Journal of Rubber Research. 20(2):87-100.
