Project Number: 6054-41430-009-000-D
Project Type: In-House Appropriated
Start Date: Nov 17, 2020
End Date: Nov 16, 2025
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.