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A study was conducted on a commercial grade hydroentanglement system to assess the effects of jet strip configuration in terms of both orifice diameter (0.10 mm, 0.12 mm, and 0.14 mm) as well as the number of orifices per inch (40 and 50) on the properties of resultant nonwoven cotton fabrics at various hydroentanglement pressures (0, 5.0, 7.5, 10.0, 12.5, and 14.0 MPa). It was found that an increase in the energy applied to the fabric web resulted in a nonwoven with increased absorbency. The results of air permeability testing indicate that a combination of variations in the orifice diameter and the number of orifices per inch as well as the energy applied determine the overall air permeability of the fabric. Tensile testing revealed that increasing the energy applied to the fabric resulted in increased strength in both the machine and cross directions and decreased elongations. These results indicate that the mechanical and performance characteristics of nonwoven cotton fabrics produced by hydroentanglement may be manipulated to obtain the desired characteristics for the targeted end-use application. [ABSTRACT FROM AUTHOR]

Several nonwoven materials were evaluated as candidates for wipe fabrics intended for sensitive applications, namely aviation maintenance. Wipes designed for this purpose must conform to specific guidelines delineated by the appropriate governing bodies. Fabric selections included both synthetic and natural staple fibers such as polyester, Lyocell and raw cotton varieties. A thorough evaluation of extractable material in an array of solvents revealed that cotton-based nonwovens as well as Lyocell have some of the lowest percentages of leachable solids. The resistance of these fabrics to abrasion and the damage incurred by them was also studied. Environmental scanning electron microscopy taken before and after the linting procedure showed that the greige cotton sample demonstrated some of the least damage. Fourier-transform infrared spectroscopy examinations of hexane extracts confirmed the absence of any silicone grease contamination on the wipes materials. Standardized tensile testing indicated that the cotton samples, especially mechanically cleaned greige cotton, have robust tensile properties that are important characteristics for wiping materials. These results indicate that cotton nonwovens, particularly greige cotton, are promising candidates for the development of future aviation and other wipes materials. [ABSTRACT FROM AUTHOR]

Greige cotton (unbleached cotton) is an intact plant fiber that retains much of the outer cotton fiber layers. These layers contain pectin, peroxidases, and trace metals that are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. When greige cotton is subjected to a nonwoven hydroentanglement process, components of the outer cotton fiber layers are retained. When hydrated, this fabric can generate H2O2 (5-50 micromolar). This range has been characterized as inducing accelerated wound healing associated with enhanced cell signaling and the proliferation of cells vital to wound restoration. On the other hand, H2O2 levels above 50 micromolar have been associated with bacteriostatic activity. Here, we report the preparation and hydrogen peroxide activity of copper/ascorbate formulations, both as adsorbed and in situ synthesized analogs on cotton. The cooper/ascorbate-cotton formulations were designed with the goal of modulating hydrogen peroxide levels within functional ranges beneficial to wound healing. The cotton/copper formulation analogs were prepared on nonwoven unbleached cotton and characterized with cotton impregnation titers of 3-14 mg copper per gram of cotton. The copper/ascorbate cotton analog formulations were characterized spectroscopically, and the copper titer was quantified with ICP analysis and probed for peroxide production through assessment with Amplex Red. All analogs demonstrated antibacterial activity. Notably, the treatment of unbleached cotton with low levels of ascorbate (~2 mg/g cotton) resulted in a 99 percent reduction in Klebsiella pneumoniae and Staphylococcus aureus. In situ synthesized copper/ascorbate nanoparticles retained activity and did not leach out upon prolonged suspension in an aqueous environment. An assessment of H2O2 effects on fibroblast proliferation are discussed in light of the copper/cotton analogs and wound healing. [ABSTRACT FROM AUTHOR]

Nanocellulose has high specific surface area, hydration properties, and ease of derivatization to prepare protease sensors. A Human Neutrophil Elastase sensor designed with a nanocellulose aerogel transducer surface derived from cotton is compared with cotton filter paper, and nanocrystalline cellulose versions of the sensor. X-ray crystallography was employed along with Michaelis-Menten enzyme kinetics, and circular dichroism to contrast the structure/function relations of the peptide-cellulose conjugate conformation to enzyme/substrate binding and turnover rates. The nanocellulosic aerogel was found to have a cellulose II structure. The spatiotemporal relation of crystallite surface to peptide-cellulose conformation is discussed in light of observed enzyme kinetics. A higher substrate binding affinity (Km) of elastase was observed with the nanocellulose aerogel and nanocrystalline peptide-cellulose conjugates than with the solution-based elastase substrate. An increased Km observed for the nanocellulosic aerogel sensor yields a higher enzyme efficiency (kcat/Km), attributable to binding of the serine protease to the negatively charged cellulose surface. The effect of crystallite size and β-turn peptide conformation are related to the peptide-cellulose kinetics. Models demonstrating the orientation of cellulose to peptide O6-hydroxymethyl rotamers of the conjugates at the surface of the cellulose crystal suggest the relative accessibility of the peptide-cellulose conjugates for enzyme active site binding. [ABSTRACT FROM AUTHOR]

Quaternary ammonium compounds, commonly referred to as quats, are cationic surfactants widely used as the active biocidal ingredient for disposable disinfecting wipes. The cationic nature of quats results in a strong ionic interaction and adsorption onto wipes materials that have an anionic surface charge, such as cellulosic materials, including cotton. The degree of adsorption of quats onto cotton nonwovens is affected by pretreatment of the substrate, more specifically whether it is a greige or a scoured and bleached fabric. This study examined the effect of varying the chemical and physical properties of solutions on the adsorption of the quat alkyl-dimethyl-benzyl-ammonium chloride (ADBAC) onto greige and scoured and bleached cotton nonwoven fabrics produced by hydroentanglement. At a constant surfactant concentration, the liquor ratio, pH, temperature, and concentrations of various electrolytes in the solution were varied and the amount of ADBAC depleted from solution was determined over time. The results suggested that a more alkaline solution increased the amount of ADBAC adsorbed onto both cotton nonwoven fabrics, while a more acidic solution reduced ADBAC adsorption. Likewise, increasing the temperature and concentration of salts in the solution reduced the adsorption of ADBAC onto the cotton fabrics. The presence of nonionic surfactants or low molecular weight quats also reduced ADBAC adsorption onto cotton fabrics in a concentration-dependent manner. The results of this study will provide guidance for optimized chemical formulations compatible with disposable disinfecting cotton-based wipes, cloths, and other cotton-containing implements intended for use in cleaning and disinfecting applications. [ABSTRACT FROM AUTHOR]

Nanocellulosic aerogels (NA) provide a lightweight biocompatible material with structural properties, like interconnected high porosity and specific surface area, suitable for biosensor design. We report here the preparation, characterization and activity of peptide-nanocellulose aerogels (PepNA) made from unprocessed cotton and designed with protease detection activity. Low-density cellulosic aerogels were prepared from greige cotton by employing calcium thiocyanate octahydrate/lithium chloride as a direct cellulose dissolving medium. Subsequent casting, coagulation, solvent exchange and supercritical carbon dioxide drying afforded homogeneous cellulose II aerogels of fibrous morphology. The cotton-based aerogel had a porosity of 99% largely dominated by mesopores (2-50 nm) and an internal surface of 163 m²·g-1. A fluorescent tripeptide-substrate (succinyl-alanine-proline-alanine-4-amino-7-methyl-coumarin) was tethered to NA by (1) esterification of cellulose C6 surface hydroxyl groups with glycidyl-fluorenylmethyloxycarbonyl (FMOC), (2) deprotection and (3) coupling of the immobilized glycine with the tripeptide. Characterization of the NA and PepNA included techniques, such as elemental analysis, mass spectral analysis, attenuated total reflectance infrared imaging, nitrogen adsorption, scanning electron microscopy and bioactivity studies. The degree of substitution of the peptide analog attached to the anhydroglucose units of PepNA was 0.015. The findings from mass spectral analysis and attenuated total reflectance infrared imaging indicated that the peptide substrate was immobilized on to the surface of the NA. Nitrogen adsorption revealed a high specific surface area and a highly porous system, which supports the open porous structure observed from scanning electron microscopy images. Bioactivity studies of PepNA revealed a detection sensitivity of 0.13 units/milliliter for human neutrophil elastase, a diagnostic biomarker for inflammatory diseases. The physical properties of the aerogel are suitable for interfacing with an intelligent protease sequestrant wound dressing. [ABSTRACT FROM AUTHOR]

The increasing use of synthetic disposable nonwoven products generates a large amount of non-biodegradable solid waste. In an effort to enhance the use of raw cotton in nonwoven wipes applications, this study compares the biodegradation of low-weight nonwoven fabrics (around 50 g/m2) made of mechanically pre-cleaned raw cotton, rayon, polypropylene (PP), and polylactic acid (PLA) in a Captina silt loam soil. The biodegradation rates of raw cotton and rayon fabrics were fitted to the first-order kinetics model with half-life values of 12.6 and 7.6 days, respectively. The slightly faster disintegration of cellulose structure for rayon was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectra, and distinct morphological changes in the fiber (cracks and breakage were prevalent in raw cotton, whereas the thinning and merging of fibers occurred in rayon) were observed during their biodegradation. PLA and PP nonwoven fabrics exhibited no weight loss during the burial periods studied, but showed some evidence of oxidation in ATR-FTIR spectra. The breaking and burst strengths of PLA fabric decreased by 45% and 23% of the original strengths, respectively, while neither significantly decreased in PP fabric. The results suggest that mixing raw cotton or rayon low-weight nonwoven wastes with surface soil provides an alternative disposal method, but this land application could not be recommended for PLA and PP nonwoven wastes. [ABSTRACT FROM AUTHOR]

The adsorption kinetics and isotherms of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on hydroentangled nonwoven fabrics (applicable for wipes) including raw cotton, bleached cotton, and their blends with polyester (PES) were studied at room temperature. The adsorption kinetics of ADBAC on all nonwoven fabrics was best described by the pseudo-first-order kinetic model. Unlike bleached cotton/PES blends, the equilibrium adsorption capacities of ADBAC on raw cotton/PES blends were enhanced in comparison with predictions based on the binary mixing rule. The adsorption rates for raw cotton, determined by the KASRA (kinetics of adsorption study in the regions with constant adsorption acceleration) model and Elovich equation, were significantly greater than those for bleached cotton, resulting in a rapid decrease of adsorption rates when blending with PES, which has a negligible interaction with ADBAC. This distinctive adsorption property of raw cotton was attributed to its unique surface characteristics induced by the hydroentangling process: retained pectin, partial removal of waxes, and surface fibrillation, which enhance electrostatic interaction, hydrophobic interaction, and accessible surface area to ADBAC, respectively. In adsorption isotherms, raw cotton/PES blends exhibited a non-linear decrease in maximum adsorption capacity and monolayer adsorption capacity, calculated by the Langmuir and Langmuir-type equations, respectively, as a function of PES blend ratio. [ABSTRACT FROM PUBLISHER]

Countless hours of research and studies on triazine, phosphonate, and their combination have provided insightful information into their flame retardant properties on polymeric systems. However, a limited number of studies shed light on the mechanism of flame retardancy of their combination on cotton fabrics. The purpose of this research is to gain an understanding of the thermal degradation process of two triazine-phosphonate derivatives on cotton fabric. The investigation included the preparation of diethyl 4,6-dichloro-1,3,5-triazin-2-ylphosphonate (TPN1) and dimethyl (4,6-dichloro-1,3,5-triazin-2-yloxy) methyl phosphonate (TPN3), their application on fabric materials, and the studies of their thermal degradation mechanism. The studies examined chemical components in both solid and gas phases by using attenuated total reflection infrared (ATR-IR) spectroscopy, thermogravimetric analysis coupled with Fourier transform infrared (TGA-FTIR) spectroscopy, and 31P solid state nuclear magnetic resonance (31P solid state NMR), in addition to the computational studies of bond dissociation energy (BDE). Despite a few differences in their decomposition, TPN1 and TPN3 produce one common major product that is believed to help reduce the flammability of the fabric. [ABSTRACT FROM AUTHOR]

In this paper, we studied the synthesis, characterization,andflammability of the water-soluble, nonhalogenated organophosphorusflame retardant (FR) dimethyl-[1,3,5-(3,5-triacryloylhexahydro)triazinyl]-3-oxopropylphosphonatefor application to cotton fabrics by nonpolymeric network. The FRwas synthesized in a one-step reaction from dimethyl phosphite and1,3,5-triacryloylhexahydro-1,3,5-triazine under mild conditions, andits structure was fully characterized by 1H, 13C, and 31P nuclear magnetic resonance (NMR), mass spectrometry(MS), and Fourier transform infrared spectroscopy (FT-IR). The finishingconditions to achieve a covalent bond between the FR and fibers wereoptimized, and the FR capability of the treated cotton was investigatedby limiting oxygen index (LOI), flame test, thermogravimetric analysis(TGA), and micro cone calorimeter (MCC) tests. This study showed thatfabrics treated with the FR are effectively flame resistant, and theFR property is enhanced by covalent bonding of the FR to fibers. [ABSTRACT FROM AUTHOR]

The growing incidence of chronic wounds in the world population has prompted increased interest in chronic wound dressings with protease-modulating activity and protease point of care sensors to treat and enable monitoring of elevated protease-based wound pathology. However, the overall design features needed for the combination of a chronic wound dressing that lowers protease activity along with protease detection capability as a single platform for semi-occlusive dressings has scarcely been addressed. The interface of dressing and sensor specific properties (porosity, permeability, moisture uptake properties, specific surface area, surface charge, and detection) relative to sensor bioactivity and protease sequestrant performance is explored here. Measurement of the material’s zeta potential demonstrated a correlation between negative charge and the ability of materials to bind positively charged Human Neutrophil Elastase. Peptide-cellulose conjugates as protease substrates prepared on a nanocellulosic aerogel were assessed for their compatibility with chronic wound dressing design. The porosity, wettability and absorption capacity of the nanocellulosic aerogel were consistent with values observed for semi-occlusive chronic wound dressing designs. The relationship of properties that effect dressing functionality and performance as well as impact sensor sensitivity are discussed in the context of the enzyme kinetics. The sensor sensitivity of the aerogel-based sensor is contrasted with current clinical studies on elastase. Taken together, comparative analysis of the influence of molecular features on the physical properties of three forms of cellulosic transducer surfaces provides a meaningful assessment of the interface compatibility of cellulose-based sensors and corresponding protease sequestrant materials for potential use in chronic wound sensor/dressing design platforms. [ABSTRACT FROM AUTHOR]

The title compound, C26H22N5O4P3·C3H6O, has been achieved in a two-step synthesis that does not require chromatography. This mol-ecule contains a seven-membered spiro-cyclic ring at two P-atom positions and a five-membered ring containing new P-N bonds at the other P-atom position. Endocyclic torsion angles about the central biphenyl C-C bonds are -41.5 (3) and -44.4 (3)°, and P-N bonds of the central P3N3 ring are within the range 1.5665 (17)-1.6171 (17) Å, while the P-O distances are in the range 1.5940 (14)-1.6041 (14) Å. One N-H group makes an inter-molecular N-H⋯N hydrogen bond, forming centrosymmetric dimers, while the other N-H group makes an N-H⋯O hydrogen bond to the acetone solvent mol-ecule. The crystal was a two-component non-merohedral twin with ratio 0.811/0.189.