2006 Annual Report
The future use of cotton in specialty textiles will be influenced by market trends. In the area of smart and interactive textiles the projected growth rate is 36% by 2009. Subsets of that textile market, which include medical and military textiles and enzymes, will grow even more rapidly. In the areas of chronic wounds and uncontrolled blood loss dressings, a variety of new medical textile cotton products will offer improved efficacy and economic alternatives for medical and military uses. The product market for wound care is now valued at $1.74 billion, and 5 million Americans suffering from chronic open wounds require care that is estimated at $5-7 billion per year and increasing at a 10% annual rate. Cotton-based chronic wound dressings and bedsore prevention bed sheets are being developed to address unmet needs in chronic wound healing. Although, laboratory experiments have produced active chronic wound dressings that have been found to greatly alleviate this problem, industrial-scale production of these high technology products remains a major problem. More than 90% of combat deaths take place before reaching the field hospital, thus the ideal method for hemorrhage control on the battlefield would include an immediate and robust clotting response within the soldiers clothing. There are currently few cotton-based dressings that accelerate clotting appropriately for battlefield trauma. A cotton-based medical textile having blood clotting properties that can be applied to both wound dressings and uniforms would meet this need. The project specifically addresses Objective 1.1 of Goal 1 of the ARS Strategic Plan to provide science-based knowledge and technolgies to generate new or improved high-quality, value-added products and processes to expand domestic and foreign markets for agricultural commodities. This project is assigned to National Program 306, New Uses, Quality, and Marketability of Plant & Animal Products, subheading New Processes, New Uses and Value Added Biobased Products. The work is dedicated solely to expanding the use of cotton fibers.
Formaldehyde is classified as a mutagen and a probable carcinogen as well as an irritant. It also causes skin allergies. Furthermore, losses of strength and abrasion resistance in commercial durable press finishing are major problems for the cotton apparel industry. These problems directly impact cotton's competitiveness with synthetic fibers. There is a pressing need for innovative processes and new crosslinking agents to regain cotton's market share for these products. Cotton and cotton/synthetic fiber blend materials are not marketed commercially for some end-use applications because of their inability to pass specific flammability tests. This places cotton at a tremendous disadvantage compared to other less aesthetically desirable products that contain a high percentage of synthetic fibers and allow passage of mandated tests. This research is relevant to the cotton farmer, the textile industry, and the consumer of textile products. With respect to large area floor covering materials, cotton is basically excluded from a market of well over five million bales of fiber. Also, cotton is excluded from the 100 percent fleece fabric market and only participates in cotton/polyester blends where the cotton content is 50 percent or less. Effective, low cost chemical modification of cotton will allow cellulose-containing products to meet flammability standards, satisfy consumer needs, and allow cotton to garner its share of targeted markets. Processing cotton with enzymes generates wastewater effluent that is readily biodegradable and does not pose an environmental threat. Given the increasing legislative pressures by governments to decrease quantity and toxicity of textile wastewaters, even partial replacement of harsh organic/inorganic chemicals with environmentally benign combined enzyme/ultrasound processing will greatly reduce the amount of hazardous textile wastewater effluents released into environment and help textile mills conform with U.S. Environmental Protection Agency (EPA) environmental regulations.
To develop cotton with accelerated clotting properties for uncontrolled blood loss, three types of grafted and crosslinked cotton fabrics have been designed and prepared. Cotton fabrics including nonwoven, print cloth and gauze were crosslinked with naturally occurring polymers (carbohydrates and proteins) that accelerate blood clotting. The biological functionality of these added polymers has been considered in the design of these dressings. For example, chitosan (a carbohydrate) binds to platelets to initiate clotting, calcium alginate (a carbohydrate) exchanges calcium for sodium and promotes the activity of calcium with clotting factors, and collagen (a protein) has coagulant activity. Thus, development of a variety of potential approaches to wound response clothing that is on site at the time of trauma assures the likelihood of greater success for interactive clotting.
FY 2007: (18) Evaluate solid-state Nuclear Magnetic Resonance (NMR) studies of labeled crosslinked cotton. (19) Construct woven and nonwoven textiles from nanocomposite fabrics. (20) Select and develop hemostatic fabrics with good commercialization potential. (21) Develop technical specifications, order, install and test the new textile processing equipment (2-Roll Laboratory Padder HVC, Laboratory Drying, Condensation and Fixation Apparatus KTF-500, Laboratory Overflow Jet Dyeing Apparatus JFO and Pad-Steam Range PSA-HTF) in order to re-establish the Textile Pilot Plant that was destroyed by Hurricane Katrina. (22) Design and manufacture two different ultrasound untis (planar and coaxial) for controlled combined high energy treatment called sonication of textile samples and enzyme processing solution. These units will be also instrumental in our new study of the enhancement of enzymatic hydrolysis of plant cellulose in bio-fuel applications by ultrasound. (23) Study the performance of specific enzymes on cotton and plant cellulose and their possible synergistic combinations under sonication conditions. (24) Improve the sensitivity of elastase colorimetric indicator on cotton using paper as a model. (25) Apply and test the application of novel silicon/phosphorus containing compounds to chemcially mofidied cotton.
FY 2008: (26) Develop technique for postively charged pre-treatment of samples of waste cotton that will be well-matched with "pillared" and "loaded" clay-based finishes. (27) Study the influence of auxiliary agents (cavitation bubbles promoters, degassing agents and wetting agents) on the combined enzyme/ultrasound processing of cotton and plant cellullose (bio-fuel applications). (28) Determine cottn crosslinking mechanism based on Nuclear Magnetic Resonance (NMR) studies. (29) Study the influence of auxiliary chemicals (surfactants, wetting agents, complexing agents, salts, etc.) on the combined enzyme/ultrasound processing of cotton. (30) Evaluate flammability of woven and nonwoven textiles. (31) Complete manufacturing trials of the cotton-based chronic wound dressing and provide product prototype for clinical trials. (32) Addfress manufacturing trials of the cotton-based chronic wound dressing for initial distribution.
FY 2009: (33) Complete the design and testing of a pilot-scale sonication reactor for continuous enzymatic bio-procjessing of cotton textiles. (34) Assess batericidal properties of samples of waste cotton pillared and loaded clay-based finishes.
REGENERATED CELLULOSE COMPOSITE FIBERS HAVE BEEN PRODUCED BY SOLUTION SPINNING TECHNIQUES. The composite fibers were processed into nonwoven substrates by small-scale paper production techniques. The fibers used to produce these materials show enhanced fire-resistant and self-extinguishing properties and are being scaled up to produce nonwoven products in collaboration with the University of Tennessee in Knoxville. ENHANCEMENT OF ENZYMATIC PROCESSING: New enzymatic preparation and finishing techniques of various cotton textiles were investigated and tested. This novel environmentally friendly process utilizes a combination of ultrasound energy and highly specific enzymes. Industrial implementation of this new textile processing should greatly reduce the amount and toxicity of wastewater effluents, energy consumption, and overall processing costs.
Five compounds (based on inexpensive and easily reactive starting materials) were prepared and their reactivity to UV light initiation and atmospheric conditions were studied. Such derivatives are members of a promising class of compounds for textile finishes that can be prepared under inexpensive and environmentally friendly conditions, such as exposure to air and ultraviolet light.
New enzymatic preparation and finishing techniques for cotton textiles were developed employing the combined pectinase/ultrasound and cellulase/ultrasound processing of variety of cotton fabrics. These environmentally friendly techniques utilize a combination of low energy, uniform sonication and highly specific enzymes. Widespread implementation of this new textile processing should greatly reduce the amount of wastewater effluents and overall processing costs.
Print cloth was treated with a chemical agent (polymer) to make it sensitive to ultraviolet light and allow a finish to be chemically bonded with the cloth. The grafting onto the textile surface has been confirmed by instrumental techniques. Standard strength tests on the print cloth indicate that a moderate loss in tear strength (12%) results from the loss of molecular weight because of the light activation, but this loss in strength is overcome by the grafting/finishing reaction because of the entanglement of the polymer chains on the surface of the cloth. The amount of agent bound to the surface was studied to determine the viability with common compounds and was found to be acceptable.
Enhanced Enzymatic Processing: Compound treatment of cotton and other cellulosic fibers with enzymes is a nontoxic, environmentally benign process that is gaining greater recognition for numerous textile-processing applications, such as desizing, souring, polishing, bleaching, stoning, and garment laundering. But in addition to numerous advantages, there are several important shortcomings in the enzymatic treatment of cotton fibers, such as more expensive processing costs and slow reaction rates and, occasionally, excessive fiber damage. Our research demonstrated that enzyme activity could be significantly enhanced by the introduction of a low energy, highly uniform ultrasonic energy field. The combined enzyme/ultrasound processing of cotton and other cellulosic fibers offers significant advantages, such as less consumption of expensive enzymes, shorter processing time, and significant decrease in the amount and toxicity of textile effluents. The predicted impact of this technology is that combining an enzymatic processing with low energy, uniform sonication could significantly enhance the performance of the variety of industrial enzymes, thus making this new, environmentally benign processing of cotton more suitable for widespread implementation.
Cotton-based Chronic Wound Dressings: ARS scientists' findings show that the activity of the enzyme, elastase, in chronic wound fluid can be lowered with modified cotton gauze. This further suggests that our modified gauze may be better suited for application to chronic wounds over standard cotton gauze in use now. This preference is scientifically based on rational design of an enzyme active site uptake affinity of harmful enzymes such as elastase. In addition burn wound dressing materials were invented to promote moist healing and retain elasticity around joints while providing water transmissibility. Blood clotting bandages were made that accelerate the rate of clotting response on the fabric, and stop the flow of blood in a bleeding wound more rapidly than regular bandages. The impact of these technologies is significant for value-added cotton and in aiding the improvement of cotton gauze dressings for chronic and burn wounds. Impact will be realized both as an agricultural commodity and on a major health care problem.
Clearly all of the above accomplishments relate to National Program 306, New Uses, Quality, and Marketability of Plant & Animal Products, subheading New Processes, New Uses and Value Added Biobased Products.