2007 Annual Report
1a.Objectives (from AD-416)
The overall goal is to develop processes to enhance the conversion of cereal crops into value added polymers and chemicals, and thus generate expanded markets for cereals and reduce dependence on petroleum.
1b.Approach (from AD-416)
Investigate the effects of stirring during cooling on the rheological properties of hot dispersions prepared by jet cooking starch in both the presence and absence of non-starch additives. Further investigate the structure, properties and end-use applications of spherocrystals formed in slowly-cooled solutions of jet-cooked starch. Modify laboratory techniques to permit commerical scale-up of processes used for deposition of thin starch coatings onto plastic surfaces and modification of these coatings by graft polymerization. Prepare starch esters having low to high degree of substitution and controlled substitution patterns with high efficiency and minimal byproducts. Characterize structure-property relationships and identify applications. Prepare new, inexpensive hydrophobic starches by reaction of starch with unsaturated hydrocarbons and characterize utility as adhesives. Prepare starch graft copolymers by reactive extrusion.
Cooperative research was conducted with Binghamton University under the non-funded cooperative agreement "Starch-Lignin Blends Materials". A manuscript on this has been accepted by J. Biobased Materials and Bioenergy. Cooperative research was conducted with Bradley University under the non-funded cooperative agreement "Nano-Structured Materials from Starch".
Simple method for preparation of starch-fatty acid esters. Starch-fatty acid esters are difficult to prepare by conventional chemical routes but can have useful properties and applications. It was found that fatty acid esters of starch can be prepared simply by heating starch under mild conditions (75 deg C) with certain ionic liquids and vinyl stearate or stearic acid. The starch fatty ester can then be isolated by precipition in water or ethanol. The ionic liquid can be subsequently recovered by evaporating the solvent and reused. This easy, green synthesis should facilitate more studies and applications of starch fatty esters and result in greater adoption of materials based on safe, renewable resources (starch from corn and fatty acids from soybean oil).
Novel catalyst for making starch esters. Corn starch has potential applications in biodegradable packaging, adhesives, coatings, dispersants, etc. but usually needs to be chemically modified. New methods of chemical modifying corn starch are needed to improve the properties of starch for these applications. It was found that a novel catalyst called scandium triflate was able to cause starch to react with acetic acid at fairly low temperatures. This is the first time that such a reaction has been reported. A novel starch having acetic groups on the surface of the starch particles only was also prepared. These findings should facilitate the preparation of new starch esters under mild "green" conditions.
Critical fluid extraction of native lipids from cornstarch. Critical fluid extraction with 75% ethanol/water as the solvent removed over 99% of the native lipid from cornstarch. The percentage of native lipid extracted depended upon the starch/solvent ratio. The pasting properties and shear storage modulus of defatted, critical fluid-extracted cornstarch differed from those of cornstarch defatted with hot 75% propanol/water, even though both samples contained only trace amounts of residual native lipid. The amount of soluble starch in pasted samples of critical fluid-extracted starch was higher than that observed with un-extracted starch. The discovery of this non-toxic method for extracting native lipids from cereal starch could lead to new end-use applications, due to the unique pasting and gelling properties of the extracted starches.
Modification of Natural Polymers by Novel Processes. A novel method for the preparation of cellulose acetate was developed involving the concurrent use of iodine, acetic anhydride and microwave. The method is simple, rapid, efficient, and solvent-less. With this method, cellulose acetates have been synthesized in minutes. This solvent-free method that we discovered would help the cellulose acetate manufacturers to prepare cellulose acetate in an environment friendly way. This method reduces the use of solvents and acids. The collaborator for this work was Eastman Chemical Company, Research Laboratories, Kingsport, TN.
Developing new synthetic techniques for starch derivatization. An improved method is needed for incorporating appropriate groups onto starch that will allow the use of controlled techniques to deliver higher value starch based materials. We have modified our synthetic approach and we have been able to place bromo-acetyl groups on starch which may serve as initiating sites for polymerization. We have also performed similar substitutions, in higher yields/grafting efficiencies, onto pullulan and cyclodextrin. End result will be a method to produce starch graft co-polymers with unique properties derived from the low polydispersity of the grafts on starch. These grafts may also have block architecture.
All of this work was carried out in support of ARS National Program 306, Quality and Utilization of Agricultural Products and addresses Problem Statement 2c, New and Improved Processes and Feedstocks.
5.Significant Activities that Support Special Target Populations
|Number of new CRADAs and MTAs||1|
|Number of active CRADAs and MTAs||1|
|Number of non-peer reviewed presentations and proceedings||3|
|Number of newspaper articles and other presentations for non-science audiences||3|
Willett, J.L., Finkenstadt, V.L. 2006. Reactive extrusion of starch-polyacrylamide graft copolymers using various starches. Polymers and the Environment. 14:125-129.
Shogren, R.L., Hochmuth, R.C. 2004. Field evaluation of watermelon grown on paper/polymerized vegetable oil mulches. HortScience. p. 1588-1591.
Biswas, A., Sharma, B.K., Willett, J.L., Vermillion, K., Erhan, S.Z., Cheng, H.N. 2007. Novel modified soybean oil containing hydrazino-ester: synthesis and characterization. Green Chemistry. 9:85-89.
Biswas, A., Adhvaryu, A., Stevenson, D.G., Sharma, B., Willett, J.L., Erhan, S.Z. 2007. Microwave irradiation effects on the structure, viscosity, thermal properties and lubricity of soybean oil. Industrial Crops and Products.
Shogren, R.L., Biswas, A. 2006. Preparation of water-soluble and water-swellable starch acetates using microwave heating. Carbohydrate Polymers. 64:16-21.
Biswas, A., Shogren, R.L., Stevenson, D.G., Willett, J.L., Bhowmik, P.K. 2006. Ionic liquids as solvents for biopolymers: acylation of starch and zein protein. Carbohydrate Polymers. 66:546-550.
Shogren, R.L., Biresaw, G. 2007. Surface properties of water soluble starch, starch acetates and starch acetates/alkenylsuccinates. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 298(3):170-176.
Peterson, S.C., Eller, F.J., Fanta, G.F., Felker, F.C., Shogren, R.L. 2007. Effects of critical fluid lipid extraction on the gelatinization and retrogradation of normal dent cornstarch. Carbohydrate Polymers. 67(3):390-397.
Fanta, G.F., Felker, F.C., Shogren, R.L., Salch, J. 2006. Effect of fatty acid structure on the morphology of spherulites formed from jet cooked mixtures of fatty acids and defatted cornstarch. Carbohydrate Polymers. 66:60-70.
Stevenson, D.G., Biswas, A., Jane, J., Inglett, G.E. 2007. Changes in structure and properties of starch of four botanical sources dispersed in the ionic liquid, 1-butyl-3-methylimidazolium chloride. Carbohydrate Polymers. 67(1):21-31.
Shogren, R.L., David, M. 2007. Biodegradable paper/polymerized vegetable oil mulches for propagation of tomatoes and peppers. Applied Horticulture Consulting. 8(1):92-94.
Biswas, A., Selling, G.W., Appell, M.D., Woods, K.K., Willett, J.L., Buchanan, C.M. 2007. Iodine catalyzed esterification of cellulose using reduced levels of solvent. Carbohydrate Polymers. 68(3):555-560.