Location: Plant Polymer Research
2020 Annual Report
Objectives
The overall goal is to produce novel bio-based materials from agricultural commodities to increase the market demand and value of U.S. non-food agricultural products and by-products, as well as to reduce the environmental impact from the plastics industry.
Objective 1. Enable, from a technological standpoint, the commercial production of new bio-based polymers, graft-copolymers, composites, and blends from polysaccharides.
Sub-Objective 1A. Selectively modify polysaccharides to provide higher product value using state-of-the-art, chemical methods and physical techniques, such as microwave, ultrasound, supercritical fluids, and on-line monitoring to produce materials suitable for coatings, personal care, food, and pharmaceutical applications.
Sub-Objective 1B. Synthesize and evaluate bio-based polymers, polymer blends and polymer composites for environmentally responsive plastics, controlled release materials, and composite materials using industrial, continuous production methods such as extrusion.
Approach
Environmental concerns over the production and disposal of polymeric materials have prioritized the creation of new bio-based materials from agricultural feedstocks. Sustainable processing technologies are also needed to replace industrial and consumer products made from petroleum based feedstock. This project focuses on making bio-based polymeric materials with useful applications from agricultural products such as starch and associated low cost corn processing and harvesting co-products. Modified biopolymers with new properties will be prepared using the latest technologies available. Specific objectives for this project include: 1) Develop novel carbohydrate-based materials, such as starches, celluloses, and chitosan, with novel structures and/or through the use of microwaves, autoclave heating, reactive extrusion, jet cooking, and other green chemical methods; and 2) Demonstrate that the biobased polymeric materials can be used in high-value applications such as composite materials, packaging, controlled release devices, and environmental responsiveness. As an example, starch-based copolymers with novel and unique properties will be compounded by reactive extrusion, characterized, and processed into films or fibers and then evaluated for targeted properties and specific applications.
Overall, this research will lead to bio-based polymer products with new or improved properties, have lower cost, are more environmentally friendly, and thus more acceptable to consumer markets. It will also generate new bio-based technologies enabling new market opportunities for agricultural products while reducing the environmental footprint relative to polymeric materials based on non-renewable resources.
Progress Report
This is the final report for project 5010-41000-174-00D which terminated in May 2020. See the report for the replacement project, 5010-41000-180-00D, "Circular Bio-economy via Value-Added Biobased Products" for additional information. Significant progress was made on both objectives which fall under National Program 306: Quality and Utilization of Agricultural Products, specifically Component 2, addressing Objective 1.3 of the ARS Strategic Plan.
Novel carbohydrate-based materials. There has been a lot of interest in using agro-based raw materials for the design of polymeric materials. A novel approach was developed to convert carbohydrates to polyurethanes through an energy-efficient and fast method with microwave heating. The polyurethanes constitute a $74.3 billion enterprise and have many applications. This research combined inexpensive carbohydrate starting materials (such as sucrose, starch, hemicellulose, and sorbitol) with the cost-effective microwave heating to produce these polyurethanes. The resulting polyurethanes could form interpenetrating polymer networks with a second polymer, thereby helping to improve the properties of the starting polyurethane.
Cyclodextrins (CD’s) are well known starch derived material. A microwave-assisted method to modify CD molecules with diisocyanates to produce polyurethanes was developed. As compared to conventional heating, this new synthetic method saved energy, significantly reduced reaction time, and improved the product yield. Our modified CD could complex with a variety of substances, e.g., drug molecules for improved solubility or controlled release, fragrance molecules for controlled release, cholesterol removal in the food industry and removal of toxic substances from the environment. It also has the potential to be used for the detection of mycotoxins for food safety applications.
Food packaging based on nanotechnology. There is ongoing interest in using agro-based polymers as alternative packaging materials and novel technologies were developed using renewable materials. Many foods are very sensitive to oxygen which contributes to food spoilage. By utilizing palladium (Pd) and cellulose nanoparticles, a novel active packaging material that could scavenge oxygen effectively and thus preserve foods by eliminating oxygen was produced. These nanocomposite films have promising active packaging properties, where the packaging material exhibits desirable functions in addition to containment of product. By incorporating Pd and cellulose nanoparticles in poly(ethylene-co-vinyl alcohol), the film has active packaging attributes, minimizing product oxidation/spoilage. These features make the nanocomposites promising candidates as active packaging materials which could be potentially used by food packaging industries.
Cellulose ester films as food packaging materials. Increased value can be obtained by incorporating essential oils into these polymers: cellulose acetate, cellulose acetate propionate and cellulose acetate butyrate. The resulting films had improved film flexibility, decreased water vapor permeability, variable opacity and possessed antimicrobial activity. The specific combination of polymer and oil gave different properties allowing for customization for specific applications. These formulations may be useful for future consideration in food packaging for all stages of food production and preservation.
Utilization of cashew gum/gelatin blend as food packaging film. A collaborative effort between ARS scientists in Peoria, Illinois, and Brazilian scientists resulted in a novel biodegradable packaging film. This film was composed of cashew gum (CG) and gelatin (G). Films with different CG/G blend ratios were found to have a range of water vapor permeability, thickness, solubility, mechanical and thermal properties, surface morphology and biodegradability that allow individual blend compositions and customization for specific applications. It is expected that the new films will fill a niche in the food packaging industry, offering a new product with unique characteristics which can be optimized. In another collaborative research effort with Brazilian researchers, a composite film was made from cashew gum and polypyrrole through electrochemistry. The use of biodegradable materials in electronics can possibly reduce the accumulation of persistent solid waste and mitigate serious environmental concerns.
A large category of biobased materials consists of plant-based oils. Several new products from plant triglycerides and related compounds were produced. Polymers were produced from epoxidized soybean oil via cationic polymerization. The molecular weight could be controlled by using fluorosulfonic acid, which was a new catalyst that produced lower molecular weight polymers. During processing, furan was generated and it could be further derivatized to form products that would have value in various end-uses, such as sunscreens to polymer modifiers.
Environmentally friendly grease from biodiesel. Biodiesel (methyl soyate) was epoxidized and made into polymers and copolymers. This is another way to convert an agro-based renewable starting material to potential products like lubricants, elastomers and coatings. Polymeric soaps (polysoaps) could also be made from polymeric epoxidized soybean oil. These new soaps may be used as grease for industrial applications.
Synthesis of fatty acid-based ionomers. One of the desirable research goals today is to convert agro-based raw materials into low-cost functional polymers. Among the readily available natural raw materials are the fatty acids that can be obtained from hydrolysis of plant oils or from the paper industry as byproducts. It has been shown that tall oil (from wood processing) fatty acids with other common materials produced a new type of polymer. Through a combination of different analytical techniques, the process in which this polymer is made is well understood which will be useful in making further improvements. An advantage of this new polymer is its low molecular weight which increases solubility. The polymer can also be made into different physical forms, such as solid block, film or foam. This work will promote the utilization and creation of a new market for bio-oil and tall oil fatty acids.
Cardanol based thickener. Cardanol is a phenolic lipid obtained from cashew nutshell liquid, a byproduct of cashew nut processing. Cardanol was chemically altered using diethyl azodicarboxylate through the ene reaction. The resulting product increased in viscosity with time and it may be useful as a thickener in oil-based commercial formulations and in other organic transformations.
A new solvent system containing water and Natural Deep Eutectic Solvents (NADES) was used for the extraction of sugars from crops. Over-ripe or rejected bananas serve as a good source for non-starch polysaccharides, which can be used as functional food ingredients and represent an opportunity for the utilization of food waste. Through the judicious mixtures of selected components, natural deep eutectic solvents (NADES) can be formed at optimal ratios at a certain temperature range. NADES is a material which is a liquid at a certain temperature, where its individual components would be solids. Using NADES with microwave heating allows for food fragrance and flavor manufacturers to extract soluble sugars from fruits like bananas. The novel processes will benefit industries by enabling them to extract fragrance and flavor selectively and faster from fruits in a more energy efficient way.
Biobased single use polyhydroxyalkanoates (PHAs) based films. There has been continuing interest in agro-based polymers that are biodegradable, eco-friendly and sustainable as alternatives to synthetic polymers based on petroleum feedstocks. The increasing awareness of the problems of single-use plastics and the presence of microplastics in the environment has reinforced the attention towards these materials. Among the agro-based polymers, PHAs appear attractive. These polyesters are derived from bacterial fermentation. PHAs are biodegradable, biocompatible and non-toxic. In collaboration with Spanish scientists, food wastes have been converted into well characterized PHAs which will have value in film or medical applications.
Xylan derivatives for packaging films. Xylan belongs to the hemicellulose family of biopolymers and serves as an under-utilized, plentiful and eco-friendly agro-based resource for product development. One of the xylan derivatives is xylan acetate, made from xylan and acetic anhydride with a strong mineral acid. Xylan acetate was produced using acetic anhydride and various safe Lewis acids. Five Lewis acids were studied (FeCl3, ZnCl2, AlCl3, SbCl3, and SnCl2) and compared to iodine as acylation catalysts. All the Lewis acids were active as catalysts for esterification but their activities differed as a function of temperature. These xylan esters would be valuable in food packaging.
Deep eutectic solids (DESs) for lignin removal. To eastablish an environmentally friendly and cheaper method to delignify lignocellulosic biomass feedstock, DESs were investigated as a green alternative to conventional solvents. Six different DESs were facilely prepared and used to delignify miscanthus and birchwood feeds, including monocarboxylic acid/choline chloride, dicarboxylic acid/choline chloride, and polyalcohol/choline chloride (ChCl). They were used for the delignification of miscanthus and birchwood feeds. The largest recovery of lignin from the miscanthus was achieved by ChCl/formic acid; for birchwood, ChCl/oxalic acid DESs provided the best results.
Accomplishments
1. Improved packaging film made from cotton co-products. In recent years, there has been increasing concern about the environmental impact of non-degradable plastics that accumulate in landfills or generate microplastics in the ocean. One solution is to replace some of the plastics with water-soluble and biodegradable materials. Poly(vinyl alcohol) (PVOH) is water-soluble and biodegradable and the right candidate for this replacement. ARS scientists in Peoria, Illinois, found that when PVOH is blended with cotton gin trash (CGT, that material left over after cotton processing) the resulting composite is more cost-effective and still biodegradable. ARS researchers found that high value composite films could be made using up to 60% inexpensive CGT. If the CGT was chemically modified, the properties of the blended films were further improved. By using a cotton waste product in a higher value product, the value of U.S. cotton co-products is increased, benefiting U.S. cotton farmers. In addition, the biodegradable biobased films will help mitigate the plastic pollution problem.
2. Bio-sensor to detect food spoilage made from cashew gum. A gum is a complex polymer made from sugars which may have other components, like proteins, in it. Gums are isolated from plants and have many uses, such as thickeners or adhesives. ARS scientists in Peoria, Illinois, collaborating with Brazilian researchers, have developed a method of chemically modifying cashew gum to provide a high value product. The modified cashew gum was used to make bio-sensors which can detect Salmonella contamination, one of the most common causes of food poisoning. Because of its importance to public health, analysis for Salmonella in food is a requirement for the regulatory agencies of many governments. The technique developed using cashew gum is a fast, specific, and quantitative test. The new biosensor has been evaluated for the detection of Salmonella in milk and found to be superior to two of the best test methods available. The biosensor shows great potential for use in the food industry. Industrial producers of foods and the ultimate consumer will benefit from improved Salmonella detection using cashew gum.
3. Green technique for producing reinforced cellulosic articles. Wood is mainly composed of cellulose and lignin. To remove the lignin is a complex and expensive process that destroys the inherent structure of the wood. ARS scientists in Peoria, Illinois, have developed a unique green method for removing lignin from woody biomass but leaves the woody cellulosic structure intact. The removal of lignin from woody biomass is accomplished by using acetic acid and hydrogen peroxide. Novel composites can then be produced by infusing the lignin free cellulosic with biobased polymers (such as corn starch or corn derived polylactic acid) which have improved properties. A variety of cellulosic based materials have been treated in this fashion, including pine or oak wood. Non-woody samples, such as soy hulls or alfalfa, can also be processed to provide cellulose composites. The wood composites produced using materials from corn will benefit corn growers and producers as well as tree processors by providing another product line for corn and woody products.
Review Publications
Biswas, A., Cheng, H.N., Kim, S., Alves, C.R., Furtado, R.F. 2020. Hydrophobic modification of cashew gum with alkenyl succinic anhydride. Polymers. 12(3):514. https://doi.org/10.3390/polym12030514.
Biswas, A., Cheng, H.N., Evangelista, R.L., Hojilla-Evangelista, M.P., Boddu, V.M., Kim, S. 2020. Evaluation of composite films containing poly(vinyl alcohol) and cotton gin trash. Journal of Polymers and the Environment. 28:1998-2007. https://doi.org/10.1007/s10924-020-01742-7.
Biswas, A., Bastos, M.R., Furtado, R.F., Kuzniar, G.M., Boddu, V.M., Cheng, H.N. 2020. Evaluation of the properties of cellulose ester films that incorporate essential oils. International Journal of Polymer Science. Article ID 4620868. https://doi.org/10.1155/2020/4620868.
Araujo Melo, A.M., Felix Oliveira, M.R., Furtando, R.F., de Fatima Borges, M., Biswas, A., Cheng, H.N., Alves, C.R. 2020. Preparation and characterization of carboxymethyl cashew gum grafted with immobilized antibody for potential biosensor application. Carbohydrate Polymers. 228:115408. https://doi.org/10.1016/J.carbpol.2019.115408.
Alves Do Nascimento, Carvalho Da Silva, L., Mendes, L.G., Furtado, R.F., Correia Da Costa, J.M., Biswas, A., Cheng, H.N., Alves, C.R. 2020. Pequi oil microencapsulation by complex coacervation using gelatin-cashew gum . International Journal of Food Sciences and Nutrition. 9:SI97-SI109. https://doi.org/10.7455/ijfs/9.SI.2020.a8.
