Antimicrobial Ag/Na carboxymethyl cotton burn dressings are developed by partial cation exchange of sodium by silver from sodium carboxymethyl cotton gauze/nonwovens through treatment with silver nitrate in an 85/15 ethanol/water medium. The ethanol/water medium is necessary to preserve the fibrous form of carboxymethyl gauze/nonwovens with a degree of substitution of 0.3 to 0.4. From the behavior of antimicrobial release and the suppression of bacterial and fungal proliferation, it is apparent that the dressings containing the silver antimicrobial agent will protect wound surfaces from microbial invasion and effectively suppress bacterial proliferation. Antimicrobial evaluations of Ag/Na carboxymethyl cotton at North American Science Associates and the Southern Regional Research Center are positive. Additionally, the results show that an enhanced burn treatment is possible using a highly moisture retentive sodium carboxymethyl gauze instead of conventional gauze now used with silver nitrate. The carboxymethyl gauze’s capacity to hold a large amount of antimicrobial solution creates the possibility for better antimicrobial treatment. The retention of a greater amount of silver nitrate solution on the dressing will require less replenishment of solution on dressings on patients, which will reduce nursing time.

Eliminating unwanted noise in passenger compartments of vehicles is important to automobile manufacturers. The ability to reduce noise inside the vehicle enhances the perceived value of the vehicle to the consumer, and offers a competitive advantage to the manufacturer. Several methods are presently employed to reduce noise and its sources, one of which uses sound-absorbing materials attached to various components such as floor-coverings, package trays, door panels, headliners and trunk liners. Natural fibers are noise-absorbing materials that are renewable and biodegradable, making them an effective choice for the automobile industry. Floor coverings using natural fibers (kenaf, jute, waste cotton, and flax) in blends with polypropylene (PP) and polyester (PET) were developed as carded needle-punched nonwovens. The acoustical absorption coefficients of these floor coverings, and of floor coverings in combination with an underpad (either a rebonded polyurethane foam, or a soft cotton nonwoven) were evaluated by ASTM E— 1050 in the frequency range of 100 to 3200 Hz. By stacking an underpad and a floor covering together, a floor covering system was created. The measurements demonstrated that each of the natural fiber-based nonwoven floor coverings contributed to noise reduction, e.g., coefficients = 0.54—0.81 at 3.2 kHz. Noise was significantly reduced with a floor covering system using either of the underpads. The most reduction occurred with a polyurethane pad; for example, for kenaf floor covering C20-1 the coefficients at 3.2 kHz were: 1.0 with polyurethane versus 0.81 with cotton pad.

Two types of nonwoven composites, uniform and sandwich structures, are produced using bagasse, kenaf, ramie, and polypropylene (PP) fibers. The experimental uniform composites include kenaf/PP (70/30), bagasse/PP (50/50), and ramie/PP (70/30). The experimental sandwich composites include kenaf/bagasse/kenaf and ramie/kenaf/ramie. A comparative study of these experimental composites is conducted in terms of mechanical properties, thermal properties, and wet properties. Composite tensile and flexural properties are measured using a desktop tensile tester. Composite thermal properties are characterized using dynamic mechanical analysis (DMA). Water absorption and thickness swelling of the composites are evaluated in accordance with an ASTM method. Scanning electron microscopy is used to examine the composite bonding structures. Statistical method of ANOVA is used for the comparative analysis. The study finds that the uniform structures have higher tensile strength and modulus, as well as higher flexural yielding stress and modulus than the sandwich structures. In terms of the wet properties, the uniform composites have less water absorption but higher swelling rate than the sandwich composites. The DMA results show that the uniform composites feature a higher softening temperature (140 C) and melting temperature (160 C), in contrast to the sandwich composites with the softening point 120 C and melting point 140 C. Within the uniform structure group or sandwich structure group, the composite thermal mechanical properties did not differentiate very much among the different natural fibers, indicating that the composite thermal mechanical strength was largely dependent upon the thermal property of the polypropylene bonding fiber.

It has long been recognized through X-ray diffraction (and other techniques) that cellulose is part crystalline and part amorphous (semicrystalline) [1]. In the crystalline (ordered) regions the cellulose chains are held in mutual H-bonding, whereas the cellulose chains do not form hydrogen bonding in the amorphous (disordered) regions. In other words, large numbers of cellulosic hydroxyl groups are available for modification. During the physical and chemical treatments, these hydroxyl groups in the amorphous regions are modified, resulting in changes in swelling and percentage crystallinity.For native cotton cellulose, portions of the fiber are arranged in an orderly fashion or lattice. The fundamental unit to make up this lattice is referred to as the unit cell. A diagram of this unit cell, as derived by Meyer and Misch [2], is reproduced in Figure 1. The cell is a monoclinic with three principal planes of reflection shown as (002), (101), and (101).Using x-ray diffraction, Sarna and Wlochwicz [3] determined that the crystallinity index (CI) of raw cotton from Uzbekistan and Turkmenistan was in the range of 73-78% and that the CI values increased with growth in the maturity of cotton fibers. These CI values were similar to those obtained by other researchers [4, 5]. 1 2 3 A setup of a continuously recording X-ray diffractometer is shown in Figure 2(a) and that of a plot of the angular dependence of the intensity of X-ray photons as a function of 2θ in Figure 2(b). The three peaks for native cotton Cellulose I are (101) at 2θ = 14.9 o , (101) at 2θ = 16.6 o and (002) at 2θ = 22.7 o . Segal and Conrad and Segal et al. [6, 7] developed an empirical method for estimating the degree of crystallinity of native cellulose (Cellulose I). The amount of crystallineAbstract An X-ray diffractometer was used to study the crystalline structure of cotton fibers after bleaching, crosslinking and a combination of bleaching and crosslinking treatments. Wet crosslinking was accomplished with formaldehyde (Form W) and dry crosslinking was carried out with either dimethyloldihydroxyethyleneurea (DMDHEU) or citric acid (CA). Results indicated that crosslinking of bleached cotton did not change the crystalline nature of cotton (i.e. it was Cellulose I), but did increase its degree of crystallinity when crosslinked with either DMDHEU or CA; crosslinked formaldehyde (Form W) was relatively less crystalline.

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