Cotton fibrils

Fibril and Acrylic Resin Mixture A blend of cotton fibrils and acrylic resin was prepared by mixing a highly fibril-lated but unstrained cotton with a 13.8% solution of Rhoplex HA-16 in a ratio of 50 1. The fibrils and water were mixed for 5 h to form a slurry containing approximately 0.5% fibrils and 0.29% Rhoplex HA-16. 

The results presented in Table III show that only the treatment with cotton fibrils (3.5% add-on) improved the tensile strength (13% increase), whereas the other treatments weakened the fabrics. Add-ons obtained with the CMC and fibril-adhesive mixtures were extremely high, ranging from 24.5 to 72.0%. The affinity between substrate and consolidant in these cases was very poor. 

Table III. Add-on and Strength of Cotton Print Cloth Degraded by Exposure to 100 Mr ad of Ionizing Radiation and Treated with Cotton Fibrils and Resins...

This investigation was supported in part by the National Museum Act, which is administered by the Smithsonian Institution. The authors are grateful for this assistance. The authors also wish to express their gratitude to Mr. Win Chuan Chang for carrying out the experiments involving cotton fibrils. 

In the three sections below we consider important areas of applications of ESCA in migration phenomena, in the synthesis of polymer surfaces by means of plasma techniques and in reactions initiated at the surface of cotton fibrils in the nitration of cellulose. 

The gross features of the equilibria which are involved in determining the overall DOS in the surface regions of cotton fibrils is outlined schematically in Figure 37. For mixed acid... 

Treatment of the algal cellulose (mixture of la—IP) from Valonia in ethylenediamine to give Cellulose IIIj simultaneously induced sub fibrillation in the initial microfihril (75). Thus crystallites 20 nm wide were spHt into subunits only 3—5 nm wide, even though the length was retained. Conversion of this IIIj back to I gave a material with an electron diffraction pattern and nmr spectmm similar to that of cotton Cellulose ip. 

Proteia and starch stains are removed by proteases and amylases, respectively. Fats and oils are generally difficult to remove at low wash temperatures by conventional detergents. By usiag Upases, it is possible to improve the removal of fats/oils of animal and vegetable origin even at temperatures where the fatty material is ia a soUd form. Particulate soils can be difficult to remove, especially if the particle sise is small. Removal of particulate soil from cotton fabric can be improved by use of a ceUulase which removes cellulose fibrils from the surface of the yam. 

The precise effects obtained are dependent on the fabric quality, the type of cellulase enzyme and the application conditions, but no mechanical forces are involved in removal of the fibrils. The process has attracted considerable attention and is now one of the main methods of defibrillating lyocell fabrics [94,101-114]. Simultaneous treatment with cellulase and protease enzymes has been applied to the biofinishing of wool/cotton blends [115]. 

Estimation of the degree of polymerization of the D-glucan chains within the cellulose fibrils is complicated by the necessity of first solubilizing the D-glucans, and this process is likely to break the chains. One estimate put the degree of polymerization at 6000 to 7000 for cellulose chains derived from cotton fibers221 (see also, Ref. 217 and references cited therein). 

As with cotton and other cellulosics, the use of the electron microscope has aided the evaluation of mechanical degradation and wear of wool fabrics. Scale removal and fibrillation were more representative of normal wear, whereas a variety of fiber faults were observed on wool fabrics abraded by laboratory testers such faults included longitudinal splitting, transverse fracture, and abraded fibrils (172). 

Cotton Cellulose To prepare a fibrillar or macrofibrillar suspension of native cellulosic fibrils, approximately 1% of cotton fiber was blended with water for 3 h in an ordinary blender and then filtered through a polyester screen having openings of 240 X 240 /un supported by a Buechner funnel to which a vacuum was applied. The filtrate was a cloudy suspension that contained fibrils and macrofibrils ranging in size from 100A to several micrometers in width. 

Fibril and CMC Mixture A blend of CMC and fibrils was made by mixing CMC prepared in the manner described above in the ratio of 1 50 with cotton pulp that had been beaten in a blender for 3 h. 

Type 6 happens in wet cotton fibers. In air-dried cotton fibers, tensile failure starts when fibrils split apart. The break generally occurs adjacent to a reversal, and the splitting is caused by untwisting effects. Finally, a tear develops along the fiber and joins up the split which follows the helical path of the fibrils around the fiber (Figures 3a and 3b). In wet cotton, a weaker attraction exists between fibrils, and the break appears as a gradually thinning out due to separate breaks. In completely dry or cross-linked cottons, the fracture runs across the fiber... 

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