Location: Plant Polymer Research
2017 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
Edible beans as food additives. ARS researchers in Peoria, Illinois, and collaborators have demonstrated that extruded high starch fraction from beans, because of its high water solubility, high water absorption and high fiber content, make a good additive ingredient for minced meat formulations, to improve moisture retention and fiber content. We characterized and determined differences in properties of pinto bean flour in the form of whole flour in order to find new edible bean-based ingredient applications. Pinto beans were milled and air classified to obtain a high starch fraction, and then extruded. Properties of non-extruded and extruded high starch fraction were compared with whole pinto flour. This result will help to expand bean ingredient options beyond the use of whole edible bean flours. Furthermore, value-added ingredients from dry beans will provide suitable alternatives to soybean which is a known allergen. The bean growers will benefit from additional uses for these beans.
Polysaccharide cashew gum as bio-based conductive film. ARS researchers in Peoria, Illinois, and collaborators have developed a novel conductive biobased film from electrodeposition of polypyrrole/cashew gum (PPy/CG). The use of biodegradable materials in electronics can reduce the accumulation of persistent solid waste and mitigate serious environmental concerns. Electronic systems consisting of renewable, biodegradable materials and minimum amounts of toxic materials are desirable. This study was carried out to investigate the electrosynthesis and the evaluation of the electrochemical, morphological, and topographical characteristics of a novel conducting PPy/CG composite material. The films were characterized by using Fourier-Transform Infrared-Attenuated Total Reflection, Scanning Electron Microscopy, Atomic Force Microscopy, and cyclic voltammetry techniques.
Alkyl Ketene Dimer (AKD) Modified Cashew Gum. Cashew gum is a polysaccharide extracted from the trunk and branches of the cashew tree. In cold water it swells into a gel but dissolves rapidly when heated. Chemical modification of Cashew gum to improve its properties will be useful for food and pharmaceutical applications. We attempted to derivatize cashew gum with a hydrophobic reagent, AKD, which could impart a surfactant-like property to this polymer. Reactions were conducted at 90°C, using Dimethyl sulfoxide (DMSO) as a solvent and 4-dimethylaminopyridine as a catalyst. Samples with various degrees of substitution (DS) from 0.002 – 0.009 were made; the samples with higher DS values tended to be insoluble. Additional testing will be needed to find out if this material can be used for drug encapsulation.
Cellulose acetate films for food packaging. Films made from cellulose esters are often used as food packaging materials. We studied the incorporation of nine essential oils into cellulose acetate, cellulose acetate propionate and cellulose acetate butyrate. The essential oils were lime, nutmeg, eugenol, pimenta berry, rosemary, petitgrain, coffee, anise, and trans-cinnamaldehyde. We observed at least four valuable characteristics: improved film flexibility, decreased water vapor permeability, variable opacity and possible antimicrobial activity. The combination of three cellulose esters and nine essential oils studied show different behavior, and each formulation can be customized for specific applications. Thus, these possible formulations may be useful for future consideration in food packaging for all stages of food production and preservation. Other uses of the essential oil-embedded cellulose esters may be found in air freshener applications or herbicidal mulches.
Improving quality and safety of fresh foods with active packaging. Packaging materials were developed using waxy corn starch (100% amylopectin) and mercerized cellulose from woody biomass and recycled newsprint. The biosynthesis of starch is tailored by its origin (e.g. rice, corn, potato, wheat) and its hybrid (e.g. normal, waxy, high amylose) to produce different mixtures of amylose and amylopectin. In addition, the molecular weights, chain length, and branching may vary. The different structures lead to different physical properties such as viscosity in solution, thermal stability, crystallinity and recrystallization. Amylose and amylopectin are packaged into granules of different sizes and shapes depending on plant origin. The different starches allow a wide range of properties as food ingredients. For example, “crispness” in a cracker can be hard (rice) or soft (wheat) depending on the flour ingredient. Starches are well known for their film forming capabilities, textural properties (viscosity), but are sensitive to moisture. In many cases, this sensitivity leads to loss of strength and integrity, but may be a benefit for absorbing or releasing flavor and aroma compounds in a food product. The film forming properties can be tailored by controlling the amounts of amylose or amylopectin in the film. The properties of amylopectin as a film former are different than high amylose materials. To impart strength and water resistance, regenerated (mercerized) cellulose from woody biomass was used. Films were constructed of varying amounts of hydroxylpropyl waxy corn starch and mercerized cellulose. Films were evaluated for mechanical strength and transport properties.
Corrosion inhibition using a natural coating. Anticorrosive exopolysaccharides (EPS) produced from cell-free cultures were produced in pilot scale quantities (1kg) for distribution of samples upon request. EPS 1501, 1498, and 1254 were cultured using enzyme, dextransucrase, from L. mesenteroides, precipitated and purified by successive ethanol-water precipitations. EPS were then drum dried into flakes. They were screened for anti-corrosive activities on Society of Automotive Engineers 1010 steel plates by re-dispersing in water and then cast or sprayed onto plates to form thin films. Film thicknesses ranged for 30 to 100 nm. Coated steel coupons were artificially corroded to test the durability of the coatings. In addition, diffusion studies were carried out in order to characterize the durability and efficacy of anti-corrosive exopolysaccharides.
Accomplishments
1. Gelatin, and cashew gum blend film for food packaging applications. Agricultural Research Service scientists in Peoria, Illinois, along with Brazilian collaborators developed a novel and biodegradable packaging film, comprising 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 film will fill a niche in the food packaging industry offering a new product with unique characteristics.
2. Polyurethanes from xylan. Xylan is a hemicellulose, which is found abundantly in nature. A novel polyurethane was developed by reacting xylan and diisocyanates. Microwave heating was found to be useful for accelerating the reaction. Several polymers with specific diisocyanate/xylan weight ratios were obtained. Characterization was conducted with spectroscopy and thermal stability tests indicated that the xylan polyurethane exhibits increased thermal stability over xylan. The poly urethanes business is a $74.3 billion enterprise and a key element of the U.S. economy. Our work utilizes inexpensive xylan to make cost effective more affordable poly urethanes that potentially could be used in building and construction, furniture bedding, appliances, footware, and electronics.
3. Corrosion inhibition using a natural coating. A corrosion inhibitor is a coating material that prevents or decreases corrosion rates when applied to a metal or alloy. Corrosion causes severe economic losses to machinery and infrastructure, and represents a safety hazard as it results in loss of strength and structural integrity. The global market of anti-corrosion coatings is projected to reach $20 billion by 2020. Agricultural Research Service scientists in Peoria, Illinois, have developed patented technology that uses a water-dispersible, natural polymer harvested from bacteria as a corrosion inhibitor. This patented technology is used at very low concentrations reducing Volatile Organic Compounds (VOCs) and can be applied by existing spray technology similar to paints. The anticorrosive coatings are very thin (nano-scale), bond tightly to the metal surfaces and can be painted as a final finishing step, providing a new product to the multimillion dollar anticorrosion industry.
Review Publications
Finkenstadt, V.L., Bucur, C., Cote, G.L., Evans, K.O. 2017. Bacterial exopolysaccharides for corrosion resistance on low carbon steel. Journal of Applied Polymer Science. doi: 10.1002/app.45032.
Biswas, A., Alves, C.R., Trevisan, M.T.S., da Silva, R.L.E., Furtado, R.F., Liu, Z., Cheng, H.N. 2016. Synthesis of a cardanol-amine derivative using an ionic liquid catalyst. Frontiers of Chemical Science and Engineering. 10(3):425-431.
Simons, C., Hall, C., Biswas, A. 2017. Characterization of pinto bean high-starch fraction after air classification and extrustion. Journal of Food Processing and Preservation Research. 41(6).
Mendes, F., Bastos, M., Mendes, L.G., Silva, A., Sousa, F.D., Monteiro-Moreira, A., Cheng, H.N., Biswas, A., Moreira, R.A. 2017. Preparation and evaluation of hemicellulose films and their blends. Food Hydrocolloids. 70:181-191.
Cheng, H.N., Furtado, R.F., Alves, C.R., Bastos, M.S.R., Kim, S., Biswas, A. 2017. Novel polyurethanes from xylan and TDI: Preparation and characterization. International Journal of Polymer Analysis and Characterization. 22(1):35-42.
Gordon, S.H., Harry-O'kuru, R.E., Mohamed, A.A. 2017. Elimination of interference from water in KBr disk FT-IR spectra of solid biomaterials by chemometrics solved with kinetic modeling. Talanta. 174:587-598.
