Enhanced Cotton (EC) for Value Added Applications research proposed here is performed within the Cotton Chemistry Utilization Unit (CCU) and intends to enable cotton’s use in expanded high value applications. The objectives cover a broad range of potential product types and thus are divergent to some extent. However, we strive to overlap in shared collaborative direction as illustrated below. The objectives of the EC Project are: 1. Resolve modifications in cotton-based textiles to enable new commercial applications of skin and wound contacting materials. 2. Enable, through chemical technologies, commercial production of conventional cotton-based (barrier protective) materials. 3. Derive novel cotton value-added products through nanocellulosic materials and conventional processes. The research objectives proposed above, in conjunction with the Cotton Nonwovens research project, are targeted to improving U.S. cotton production by increasing the demand for domestic cotton. Increasing domestic consumption will come from identifying key consumer unmet needs specific for cotton, and areas where domestic cotton is required for end use products. Historically, solutions to downturns in U.S. cotton consumption have come from infusing cotton with new technologies that impart a competitive edge to cotton (e.g. permanent press) over synthetic fibers, or creating a customer-expedited supply of high quality cotton products that compete well with overseas production. However, in the current global market, development of proprietary technologies specific to the domestic consumption of cotton, are needed. Each of the research areas listed above is critically important at this time because each, if successful, will contribute greatly to increasing the domestic demands of cotton.
For Objective 1, a broad set of characteristics requires a varied approach to de novo design and preparation of cotton-based prototypes as body-contacting material. The target products of the approach are hemostatic, antimicrobial, chronic wound dressings and incontinence topsheet absorbents. Although each of these product areas share similar fabric characteristics they differ in functionality. Experiments for these four fabric groups will vary based on the functional target use. Evaluation of the influence of fiber structure on fabric surface polarity is important to hemostatic and incontinence fabrics, and design features at the cellulose crystallite level and molecular modifications are important to the chronic wound dressing. These will be assessed for activity through in vitro assessment models based on current leads, and prototypes developed from structure/function relations. Structure-activity relations of the fiber/fabric derivatizations will be examined at the fiber, microfibrillar and molecular level using fiber surface chemistry, electrokinetic, fluorescence, colorimetry, infrared spectroscopy, x-ray crystallography, and computational chemistry. The derivatized cotton materials will utilize chemical and physical cotton fabric modifications as are required to optimize activity and may employ some synthetic modifications i.e. protease sensor constructs are outlined in Obj. 3. For Objective 2, discovery and development are outlined in three phases. In Phase 1, principle focus will be on the Layer-by-Layer (LbL) technology which will be applied to cotton nonwovens and compared on both bleached and greige cotton. Multifunctional activities will be explored i.e. antimicrobial, UV protection, and flame retardant activity. Phase 2 will predominantly be devoted to optimizing LbL functional properties to correspond with environmentally friendly, non-toxic approaches to conferring functionality i.e. antimicrobial, UV protection, and flame retardant activity while exploring ways to improve fabric hand. Phase 3 focus will be on working with stakeholders to identify LbL fabric technology with interest in applications i.e. military, sporting, wilderness medicine, fire barriers etc., and identifying key functionalities for cotton-based marketing and price point economy. For Objective 3, mechanical milling of feedstock materials will yield a uniform-sized intermediate raw material, which will be subjected to alkaline and oxidative chemical treatments to remove pectin, hemicellulose and lignin. The ensuing suspension of nanocellulose will be hydrolyzed with dilute sulfuric acid and then subjected to high-pressure homogenization, leading to a sulfated cellulose nanofiber (sCNF). The sCNF products obtained by this process will be characterized by an array of analytical methods as detailed in the Methods section of (Jordan, Easson et al. 2019). From these isolated and characterized products, hydrogels, thin films and aerogels will be prepared and nanomaterial-treated cotton analogs will be prepared to obtain an initial nanomaterial-treated composites. Several lead compounds will be prepared to explore different chemistries.
Progress was made by ARS researchers in New Orleans, Louisiana on all three objectives, all of which fall under National Program 306, Component 2, Quality and Utilization of Agricultural Products, Non-Food. Progress on this project focuses on Problem 2A to increase or protect the market demand for (or increase the value of) existing U.S.-produced non-food bio-based products derived from agricultural products and byproducts. ARS researchers in New Orleans, Louisiana, have developed new products, applications, and processes for expansion of domestic cotton in the areas of: (1) moisture control properties and hygienic and cotton fabric hand applications; (2) conversion of biomass to nanocrystals; (3) flame retardant cotton; (4) utilization of enabling technologies for improved flame retardant cotton; (5) Sensors that utilize a form of cellulose with high surface area to detect disease biomarkers; (6) cotton-based blood antibacterial and antiviral fabrics for wound dressings and face masks; and (7) hemorrhage control dressings with improved clotting properties. Intelligent Cotton Dressings with Protease Sensors in Support of Objectives 1 and 3: ARS researchers in New Orleans, Louisiana believe proteins play an important role in wound healing. Proteases are proteins that cut up other proteins. An overabundance of proteases in a wound is harmful, and results in loss of a protein's ability to function in wound healing. Sensors that detect destructive levels of proteases, which are present in wounds that fail to heal, are important for human healthcare. These types of sensors are an important tool for doctors and nurses to use at a patient’s bedside to predict and improve wound healing. ARS researchers in New Orleans, Louisiana prepared a form of modified cotton that detects proteases destructive to wound healing. To improve on this ARS researchers in New Orleans, Louisiana treated cotton materials with a special form of cellulose designed to fit and conform easily to a wound dressing. The special form of cellulose is a gel useful for a wide variety of medical applications. The cellulose gel, also extracted from cotton, improved the sensor’s ability to detect destructive wound proteases. The approach to test the sensor’s function used techniques that visualize how the sensor works. The work resulted in a tenfold improvement in the sensor’s detection of destructive proteases that block wound healing. Progress with the research has made the sensor more useful at detecting agents that are harmful to wound healing. Cotton-Based Sensor Assembly and Design to Detect COVID-19 associated virus in Support of Objective 1 and 3: Combating the virus that has caused the COVID-19 pandemic has been a challenge for healthcare professionals and the public at large. ARS researchers in New Orleans, Louisiana have investigated how cotton is applicable to both the detection and prevention of virus infection. ARS researchers in New Orleans, Louisiana work on detecting and preventing the spread of the virus first focused on how the virus enters human cells. The virus enters human cells by binding to the virus surface. Design of sensors that detect the virus use information about the virus process of cell entry. ARS researchers in New Orleans, Louisiana used this concept to help design agents (peptides), which were prepared and studied for their ability to adhere to components (proteins) on the surface of the virus. The ‘virus-binding peptides’ were then prepared by ARS researchers in New Orleans, Louisiana and their structure studied. Using a special technique to study the peptides’ structure, ARS researchers in New Orleans, Louisiana showed that the shape of the peptides influences their ability to adhere to the virus. Further work by ARS researchers in New Orleans, Louisiana will be required to apply the information obtained from the study to the design of cotton sensors and potentially agents that combat the virus. Thus, the goal is to use information from this study to both detect and combat viruses and their spread. Construction and Testing of Cotton-Based Face Mask with Antiviral Activity in Support of Objective 1 & 2: Facemasks have been widely used to combat infection resulting from the COVID-19 pandemic. Some facemask designs use a double layer of cotton cloth to prevent the virus from contacting the face due to aerosolized virus. The Centers for Disease Control (CDC) has approved this type of design for use by the public. However, facemasks that inactivate the virus are scarce. ARS researchers in New Orleans, Louisiana revealed that a cotton fabric treated with small amounts of vitamin C destroys two types of viruses. The results of virus activity tests on the fabric revealed a 99.99 percent reduction of a virus like polio and a 90 percent reduction of coronavirus. ARS researchers in New Orleans, Louisiana prepared cotton facemasks with the modified fabric, according to CDC specifications. The facemask also tested positive for breathability and is within acceptable breathability limits for human use. The mask provides an improved, safe, economical, and sustainable alternative to both disposable and reusable cloth masks. Stakeholders are working on commercializing the technology. Cotton By-Products to Increase Paper Strength In support of Objective 3: The paper industry is interested in improving paper strength. There are many ways to make paper stronger, but many of these ways are harmful to the Earth and the environment. It is important to find new methods to make paper stronger without hurting the Earth. ARS researchers in New Orleans, Louisiana found that in a series of tests, paper strength increased after treatment with small amounts of cotton-derived fibers, crystals, and protein. Testing of the treated paper showed a 97% improvement in strength compared to untreated paper. Since each compound used comes from cotton, a natural substance, the treated paper product is better for the environment. This improved strength property is expected to be useful in the packaging industry. The processing of field cotton with ginning produces a high volume of cotton waste. ARS researchers in New Orleans, Louisiana are looking for high value uses of the cotton waste. The specific types of cotton gin waste are termed gin motes and cotton gin trash. Lignin, which is a naturally occurring rigid polymer found in most plants, is a part of the cotton gin waste. ARS researchers in New Orleans, Louisiana used gin motes and gin trash to prepare a special type of cellulose fiber that contains lignin. The special material is lignin-containing nanofibers (LCNFs). The amount of lignin measured in LCNFs varied from 3% to 18%. The different amounts of lignin gave the LCNFs different properties useful for high value products. LCNFs from gin motes were larger, were more organized and heat tolerant and tended to group together in water. Those from gin trash were less resistant to heat, were less organized, and shorter. Because of this, these LCNFs did not bunch together. This finding is important when mixing LCNFs with plastics, when using LCNFs as thickening agents, or when using LCNFs to strengthen materials. These results suggest potential use in bio-based plastics, packaging, and tissue engineering products.Cotton-Based Nanocellulose from Cotton By-Products in Support of Objective 3:Cellulose nanocrystals (CNCs) are small, hard, and well-organized parts of cotton fibers. They are prepared using harsh conditions and strong acids. This produces a lot of excess waste. To reduce waste, CNCs were prepared from cotton gin motes using dilute acids and an ionic liquid. The ionic liquid can be recycled, which is safer for the environment. Using this method, the CNCs were larger, which can be important for preparing gas absorbents and emulsions. They were also more tolerant to high heat. This has other benefits. Some uses require CNCs that can resist heating. Future work will look at other ionic liquids to see what effect they have on CNCs properties.Flame Retardant Cotton In support of Objective 2: Innovative approaches to prepare flame retardant cotton fabrics are required to advance the industrial efficiency of developing low-cost and effective flame retardant cotton. ARS researchers in New Orleans, Louisiana used microwave technology to modify cotton fabrics with minimum amounts of solvent. The small amount of solvent used is an advance over current industrial processes to make flame retardant cotton. Thus, a rapid chemical treatment of cotton fabrics is use of microwave-assisted technology. The cotton fabrics designed contained environmentally friendly molecules including urea, diammonium phosphate, and phosphorous nitrogen containing compounds. ARS researchers in New Orleans developed an efficient method for the chemical treatments of a series of fabrics that tested for positive flame retardant activity. The treatment yields an effective flame retardant fabric, resulting in the addition of more of the chemical to the fabric (100 percent add-on). The compounds are also low-cost and commercially amenable to large-scale production of cotton fabrics. Microencapsulation in Support of Objective 2: Microencapsulation is a rapidly growing technology used commercially to confer properties suitable for protection against microbes, mosquitoes, and flame retardant activity. The technology is adaptable for cotton textiles. Recently, ARS researchers have developed microcapsules using flame retardant, mosquito repellant, and antimicrobial compounds such as phosphorus–nitrogen containing small molecules and essential oils. Microcapsules are prepared by depositing a thin polymeric coating on small solid particles or liquid droplets. Cotton fabrics treated with microcapsules will be studied for their slow time-release. ARS researchers in New Orleans demonstrated preliminary results that validate the design of the microcapsule-treated fabrics using standard test methods.
1. Safe, environmentally friendly cotton fabrics use vitamin C to promote disinfectant activity against bacteria and viruses. ARS researchers in New Orleans, Louisiana, believe there is a worldwide demand for effective, safe, and economical textile fabrics that prevent the spread of infectious diseases. This is apparent from an eighteen-billion-dollar annual market for textiles that prevent the spread of microbes and viruses. Moreover, the outbreak of COVID-19 has increased that market demand. However, an issue in addressing the current need for these types of fabrics is development of a low-cost, non-toxic treatment that is safe and effective. To address the demand for improved microbe fighting textiles, ARS researchers in New Orleans, Louisiana, developed a low-cost treatment of cotton fabrics. The new treatment uses small amounts of vitamin C applied directly to the fabric. The treated fabric prevents growth of bacteria and viruses at the 99.99 percent level. The treatment is also ideal for manufacturing lines and streamlines the production process. ARS researchers in New Orleans, Louisiana are working with the cotton and textile manufacturing industry to transfer the process. The process for making the new fabric is also sustainable and employs a type of domestic cotton that will boost cotton production in the United States. The new cotton fabric will be applicable to a wide range of textile uses including facemasks, wound dressings, hygienic wipes, and fabrics used as barriers to the spread of microbes and viruses in hospitals.
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