Location: Bioproducts Research2013 Annual Report
1a. Objectives (from AD-416):
Objective 1: Develop novel commercially viable composite materials from agricultural residues and industrial crops. a. Develop novel commercially viable fiber-reinforced composite materials. b. Develop novel commercially viable composite materials for agricultural applications and consumer goods. Objective 2: Develop novel technology to enable the commercial production of nanofibers from biopolymers. Objective 3: Develop commercially viable biobased polymers and polymer blends with improved functionality. Objective 4: Develop technologies to enable the commercial production of non-fuel commodity bioproducts from agricultural and biorefinery feedstocks and byproducts.
1b. Approach (from AD-416):
Novel commercially viable composite materials will be developed from agricultural fibers and binders. Fiber composites with superior strength and flexibility will be made by uniformly distributing agricultural fibers in matrices using and array of dispersants. Matrix materials will include biopolymers and inorganic binders. Fiber reinforced composites will also be made using micro and nanofibers made from biopolymers. Composite materials with liquid activated clumping properties will be made using agricultural binders with high molecular weight and strong hydrophilic properties. Composite materials that function as control-release devices will be developed both for controlling important agricultural pests and for providing plant nutrition and protection. The devices will utilize biodegradable, natural polymers and beneficial soil microbes. In addition to composite materials, micro and nanofibers and/or nanoparticles will be made from biopolymers using a solution blow spinning technology recently developed. Biopolymer solutions will be used to make an array of micro and nanofibers with active agents that provide functionality for applications for medical products and personal hygiene items. Nanoparticles from starch and/or cellulose will be produced by chemical and mechanical means. The materials will be used to make nanocomposites with improved strength and modulus. Low molecular weight polyesters will be made based on di and triols/diacids that can plasticize polylactic acid (PLA) or polyhydroxyalkanoates (PHA). PLA and PHA polymers containing the plasticizers will be tested for strength and stability by recording mechanical properties. Green pathways for making styrene and terephthalic acid will be explored along with other WRRC cooperators. The Bioproducts Group’s main focus in this collaborative effort will be to assist in characterizing the mechanical and physical properties of the biopolymers and partnering with industry to facilitate scale-up. Non-fuel commodity bioproducts from crop residues, fish waste and wheat gluten will be made. Cellulose fiber will be extracted from crop residues and processed into bioproducts including agricultural mulches and tessellated fiber board. Bioproducts from fish waste will include gelatin polymers for biomedical applications such as tissue scaffolding. Nanofibers from fish gelatin or blends of fish gelatin and other polymers will be made by electrospinning. Processing parameters will be optimized and fiber properties will be characterized using microscopy and analytical methods. Antibiotics will be incorporated into the fibers and films. The antimicrobial effectiveness of fibers will be compared to films as to their effectiveness against different bacteria using an overlay inhibition technique. Work on wheat gluten bioproducts will also be performed with the goal of developing natural protein polymers from vital wheat gluten that can be chemically modified to impart greater ability to absorb water. Formerly 5325-41000-044-00D (6/09). Replacing 5325-41000-051-00D (8/10)
3. Progress Report:
Efforts were made to develop new composite materials using agricultural fibers as specified in objective 1 of the project plan. Polylactic acid (PLA)/fiber composites were made using kenaf core which is a byproduct of the kenaf fiber industry. The core was a suitable filler and produced superior results compared to PLA/wood flour composites. Starch/PLA composites were made using starch concentrations of 70% or higher. In these composites, the starch formed the continuous phase and the PLA was the discontinuous phase. PLA was infiltrated into the starch matrix by solution infiltration. The composites had good strength and improved moisture resistance. In another project, various torrefied agricultural waste by-products were used in composite materials. We incorporated the torrefied biomass as fillers into different polymers to produce composites with improved properties. Progress was made on objective 2 where nanofibers were produced from fish gelatin and PLA using both electrospinning and solution blow spinning. Antimicrobial agents were incorporated into these fibers for controlled-release applications. The use of PLA nanofibers in metering the release of essential plant oils was also investigated. The nanofiber composites had improved mechanical properties and effectively controlled the release of the oil. In research focused on objective 3, progress was been made in further developing a block-copolymer of d-lactide and a polyester for use in plasticizing PLA. The plasticizer improved the heat distortion temperature of PLA and a bio-based filler has been identified that further improved the heat distortion temperature. Efforts are being made to provide quantities of product to potential customers for evaluation. As part of objective 4, phosphoric acid derivatives of vital wheat gluten were made and tested as sorbents for water, salt solutions, and ethanol in laboratory environments. The modified wheat gluten absorbed up to 78 times its weight in water. These materials were also added back to unmodified vital gluten at low concentrations and significantly altered the properties of the vital gluten during mixing by extending the stability of the material and retarding protein agglomeration. This suggests their possible use as a powerful modifier suitable for food applications and in preparing biobased product resins. The high degree of hydrophilicity may also overcome brittleness often reported for molded objects from biopolymers at low relative humidity. Several computational methods for analysis of gluten data using unique capabilities of Mathematica were advanced to enhance interpretation of gluten protein composition reported in two-dimensional electrophoresis vis a vis a polymer resource rather than a bread constituent. One of these methods led to a cover illustration for the cited article by Robertson, et al (Journal of Applied Polymer Chemistry).
1. Chemical alteration of wheat gluten to create superabsorbents. Native or vital gluten or chemically modified wheat gluten can be an inexpensive polymer resource for bio-based products. Ressearchers at Albany, Calfornia, combined vital gluten with citric or phosphoric acid. This changed the insoluble gluten with a low water absorbency into a superabsorbent, capable of forming a gel that absorbs 40-70 times its weight in water. It is also effective in salt solutions or solvents, which means it can be used in spill cleanup, disposable diapers, in surgical dressings, or as a modifier in foods and biobased products.
2. Slow release of active ingredients in foods and drugs. Metering the release of active agents is of growing interest as a means of providing sustained dosages and avoiding over-dosing. Researchers in Albany, California, produced nanofibers from fish gelatin and poly lactic acid (PLA) using both electrospinning and solution blow spinning. Antimicrobial agents were incorporated into these fibers as a means of achieving controlled-release. The fibers were effective in providing slow-sustained release of the active agent. This research could help provide better drug delivery at safe and sustained amounts.
3. Adding value to agricultural waste. Agricultural waste that is stockpiled can be challenging to properly dispose. One solution is to convert the waste into value-added products. Researchers in Albany, California, are working closely with a collaborator partner to develop an economical process for torrefying agricultural waste. The torrefied product is being evaluated as a filler/colorant in plastic composites and as a bio-coal fuel product. This research is being used by a commercial partner to develop a value-added use for agricultural biomass.
Robertson, G.H., Blechl, A.E., Hurkman II, W.J., Anderson, O.D., Cao, T., Tanaka, C.K., Gregorski, K.S., Orts, W.J. 2013. Physical characteristics of genetically-altered wheat related to technological protein separation. Cereal Chemistry. 90(1):1-12.