1a. Objectives (from AD-416):
Objective 1 - Develop chemistries and treatments that enable new cotton-based products for biomedical and specialty applications. Objective 2 - Develop enzyme-based technologies that enable new cotton-based products for decontamination applications. Objective 3 - Develop new finishing chemistries and innovative treatment processes that enable new cotton-based products with flame retardancy and moisture control. Objective 4 - Develop environmentally friendly cotton, dyeing and finishing processes based on the combination of sonication and enzymatic technologies.
1b. Approach (from AD-416):
The U.S. cotton industry continues to face supply and demand concerns. Since cotton is used in manufactured products, the industry has been challenged by the downsizing of manufacturing facilities that traditionally provide a major underpinning to domestic cotton consumption. Thus, with the goal of giving U.S. cotton utilization a competitive edge, research emphasis will be placed in cotton fiber science and product development where consumer and industrial needs are unmet and show promise. Some of the areas of consumer need for cotton products and process potential are: specialty nonwoven pads and wipes medical/hygiene, apparel/home furnishings, and enzymatic bio-processing. The targeted research in the areas of synthetic chemistry, enzymatic, bio-processing, flame retardant chemistry, and analytical cotton fiber science will be undertaken by the collaborative efforts of the Cotton Chemistry Utilization Unit to yield new cotton products. Collaboration and synergy with the research unit’s cotton nonwoven project in the areas of value-added cotton materials, enzymes, processing, and environmental sustainability make the likelihood of success high. Products that are envisioned to arise from this research include medical, hygiene, and hospital materials, broad spectrum anti-microbial and decontamination wipes, durable low-cost flame retardant apparel and home furnishings, and ultrasonic approaches for smooth finishing of cotton textiles. This proposed research also takes into account preserving the environment and economical cost. Research emphasis will be placed on developing approaches to enable a comprehensive understanding of the relation of structure to function on modified cotton for a broad range of potential uses.
3. Progress Report:
Agricultural Research Service (ARS) scientists at Southern Regional Research Center (SRRC), New Orleans, Louisiana, have developed new products, applications, and processes for expansion of domestic cotton in the areas of: 1) Flame Retardant Technology; 2) Nanotechnology; 3) Medical and Hygiene Products; 4) Bioprocessing; and 5) Biofuel Technology. Progress in these five areas of cotton research is as follows: 1) Flame Retardant Technology: A phosphoramidate derivative was prepared through a short organic syntheses route, and add-ons of 4-9% from aqueous solution formulations were found on cotton fabrics such as print cloth, twill, and fleece. All fabrics performed well in flammability tests [American Society for Testing and Materials (ASTM) method]. 2) Nanotechnology: A biosensor with potential for point of care diagnosis usage was made from cotton cellulose nanocrystals and protease substrate peptides. The biosensor is a sensitive colorimetric and fluorimetric detector of a destructive enzyme found in many chronic diseases. 3) Medical Products: Greige cotton was shown to posses properties associated with accelerated clotting and wound healing. Blood clotting studies revealed that nonwoven greige cotton accelerates coagulation over scoured and bleached cotton, and generates low level hydrogen peroxide levels associated with enhanced granulation tissue. 4) Hygienic Products: Nonwoven greige cotton was shown to possess fluid uptake and material surface properties similar to absorbent incontinence product materials making it of special interest to a high volume incontinence products market where cotton has historically been under used.
1. Flame retardant (FR) technology. Combining analytical techniques such as Fourier Transform Infraed Spectroscopy-Thermogravimetric Analyzer (FTIR-TGA) are proving valuable in delineating the kinetics of cotton pyrolysis and helping to guide chemical pathways to improve the main flame retardant product. Agricultural Research Service (ARS) scientists achieved an understanding of the flame retardant mechanism and in the process explained the flame retardant design criteria and the chemistry to achieve the new flame retardant compounds. The new compounds and their textile formulations will be of interest and use to professionals engaged in new materials design in textile industries to create new marketable uses such as firefighter apparel, institutional draperies and upholstery, carpet, transportation blankets and seat covers, children’s sleepwear, and bedding.
2. Cotton-based nanotechnology. Advances in biosensor technology hold promise to revolutionize healthcare, and agriculture through diagnosis at the point of care. Cotton cellulose nanocrystals possessing high surface area were shown to be excellent transducer surfaces to increase detection sensitivity. Bioactive conjugates of nanocrystalline cellulose were shown to increase efficiency, sensitivity, and high enzyme affinity. These were used to prepare a sensitive biosensor for a clinically relevant protease.
3. Medical products. It has been determined that nonwoven greige cotton has haemostatic, protease-lowering, and low-level hydrogen peroxide production properties that are of value in wound healing. These properties can be combined into single or multiple dressing prototypes useful as functional haemostatic and semi-occlusive wound dressings (dressings that promote moist wound healing). By retaining the outer layer of the cotton fiber’s native constituents and introducing absorbency through nonwoven processes that expose the cellulosic layer, simple cotton wound dressings can be improved in functionality including: 1) semi-occlusive properties, non-adherent and non-linting, from retention of calcium coordinated pectin and lipids on the outer cotton fiber layer, 2) it promotes blood clotting and low-level hydrogen peroxide production from pectin, 3) traps proteases by a net negative charge due to pectin and lipids on the outer portion of the cotton fiber, and web-formed micro channels from the hydroentanglement process. This was exhibited by a stakeholder at a national meeting on wound care.
4. Hygienic products. Nonwoven greige cotton was also found to possess properties suitable for use in the absorbent layers of incontinence products. The ability of the nonwoven greige cotton to perform similar to or better than top sheets and acquisition/distribution layers in commercial products was demonstrated using industry approved tests for strikethrough, rewet, and acquisition. The correlation of fabric surface properties of absorbency, swelling, and surface polarity to actual performance has attracted industrial interest toward incorporation into commercial products, and the enhanced use of cotton in nonwoven products.
5. Bio-processing of cotton textiles. A newly discovered polygalacturonase enzyme has bio-scouring enzymatic activity comparable to a commercially available source. Enzymes offer an environmentally friendly alternative to traditional caustic treatments currently used in the industry. Use of enzymes reduce or eliminate caustic waste streams which consume large quantities of water and require neutralization. The enzymatic bio-scouring method is a cost and time saving alternative to the existing method. The combination of ultrasound and enzymes improve cotton wet ability as measured by American Association of Textile Chemists and Colorists (AATCC) RA63 Water Resistance, Absorbency, and Wetting Agent Evaluation Test. Ultrasound-enhanced enzymatic bio-processing is effective across a broad range of fabric weights and has an application as an alternative fabric preparation method for the textile dyeing industry.
Condon, B.D., Easson, M.W., Yachmenev, V., Lambert, A.H., Smith, J.N. 2012. Low-level, uniform ultrasound field effects on enzymatic bioprocessing of greige cotton using three fabric weights. American Association of Textile Chemists and Colorists Review. 12(6):45-50.