Oxidized cellulose fibers

Typical fillers calcium carbonate, kaolin, carbon black, talc, zinc oxide, cellulose fibers... 

Cell-150 signify oxidized cellulose fibers with carboxylic content equal to 150 mol/g... 

S. Alila, F. Aloulou, D. Beneventi, and S. Boufi, "Self-Aggregation of Cationic Surfactants onto Oxidized Cellulose Fibers and Coadsorption of Organic Compounds", Langmuir, Vol. 23, pp. 3723-3731,2007. 

Cellulose LiCl/DMAc, NMMO/water Crystallization, oxidation to produce oxidized cellulose fiber [128]... 

The cellulose dissolving potential of the amine oxide family was first realized (79) in 1939, but it was not until 1969 that Eastman Kodak described the use of cycHc mono(/V-methy1amine-/V-oxide) compounds, eg, /V-methylmorpho1ine-/V-oxide [7529-22-8] (NMMO), as a solvent size for strengthening paper (80) by partially dissolving the cellulose fibers. 

Natural Products. Many natural products, eg, sugars, starches, and cellulose, contain hydroxyl groups that react with propylene oxide. Base-cataly2ed reactions yield propylene glycol monoethers and poly(propylene glycol) ethers (61—64). Reaction with fatty acids results ia a mixture of mono- and diesters (65). Cellulose fibers, eg, cotton (qv), have been treated with propylene oxide (66—68). 

Electric discharge (corona, cold plasma) is another method of physical treatment. Corona treatment is one of the most interesting techniques for surface oxidation activation. This process changes the surface energy of the cellulose fibers [28]. In the case of wood surface activation it increases the amount of aldehyde groups [291. 

The chemistry of quinone dyes has been discussed in a series of books entitled The Chemistry of Synthetic Dyes, edited by Venkataraman.1 The general chemistry of quinoid compounds has been discussed by Patai.2 There have been many books that cover quinoid compounds as dyes and pigments but very few discuss the chemistry of the corresponding leuco dyes. Traditional vat dyes are applied to cellulosic fiber in the leuco form. The chemistry of the leuco form of vat dyes is rather simple. Some leuco quinones are quite stable in the solid state and can be stored for a year. Other leuco dyes are unstable in solution and gradually undergo aerial oxidation. 

Anthraquinone leuco dyes are widely known as vat dyes.10 Vat dyes possess extensively conjugated aromatic systems containing two or more carbonyl groups, e.g., anthraquinone, indigoid chromophores. The colored form of vat dyes are insoluble in water. The dyes are applied by a process whereby the dye is converted to the reduced form (leuco dye) which is soluble in water and can penetrate into a cellulosic fiber. On exposure to the atmosphere the leuco form is oxidized to the original quinoid form which then precipitates as an aggregate. Vat dyes generally have excellent chemical and photochemical stability. 

Y. Kurokawa, T. Sano, H. Ohta, and Y. Nakagawa, Immobilization of enzyme onto cellulose-titanium oxide composite fiber. Biotech. Bioenerg. 42, 394—397 (1993). 

Newcell A process for making reconstituted cellulose fibers by dissolving cellulose in N-methyl morpholine N-oxide and injecting the solution into water. Invented in 1977 by Akzona, NC. 

It is difficult to find any definitive information that indicates ozone damage as extensive as that suggested in the mri report. The latter identified cotton, nylon, and rayon as particularly susceptible to ozone. The oxidation of cellulose fibers by ozone was the subject of a study in 1952 that showed that dry cotton was not seriously degraded by ambient ozone. In more recent studies, these conclusions were confirmed. The only information available on fibers other than cotton addressed the effect of ozone on modacrylic, acrylic. Nylon 66, and polyester fabrics.The results indicated minimal effects on these fibers. 

Oxidized cellulose is very similar to normal cotton but with a defined texture and an acid taste. The material tends to disintegrate on handling. Under the microscope, the fibers are very similar to those of normal absorbent cotton. Oxidized cellulose is used as an absorbable haemostatic in many types of surgery. It is incompatible with penicilline and can not be heat-sterilized. 

Sulfur Dyes. These dyes arc synthesized by heating aromatic amines, phenols, or nitro compounds with sulfur or. more usually, alkali polysullides. Sulfur dyes are used for dyeing cellulosic fibers. They are insoluble in water and are reduced to ihe water-soluble leuco form for application to the substrate by using sodium sulfide solulion, The sulfur dye proper is then formed within the fiber pores by atmospheric oxidation. Sulfur dyes constitule an important class of dye lor producing cost-effective tertiary shades, especially black, on cellulosic fibers. 

Anthraquinone vat dyes are water-insoluble dyes. They arc converted til leuco compounds (anthrahydroquinone.s) by reducing agents such as sodium hydrosulfite in alkaline conditions. These water-soluble leuco compounds have an affinity to cellulose fibers and penetrate them. After reoxidation by means of air or other oxidizing agents, the dye becomes water-insoluble again and fixes firmly on the fiber. 

In Activity 3.4, paper is made in a basic solution. For paper in which wood fibers are used, NaOH (sodium hydroxide) can make the pulp mixture basic by providing an excess of OH" ions. The NaOH breaks down cellulose fibers in the wood and other plant materials that form the primary paper structure. A suspension of these fibers can be placed on fabric on an embroidery hoop. Also, CIO- ions can act as oxidizing agents in the basic solution. Finally, KA1(S04)2 12H20 (potassium aluminum sulfate Alum) is added to the cellulose fibers to coagulate the pulp (clay is added when it is not naturally present). The aluminum ion (Al3+) helps the clay loosely bond to the cellulose fibers so that the resulting paper is dense and smooth. 

Research on the weathering and mechanism of photo-degradation of cellulose is reviewed. It is pointed out that many factors such as dyes and delustrants, in the case of regenerated cellulose fibers, as well as the ambient atmosphere and the wavelength of the irradiation may affect the rate of degradation. Recent work on the photodegradation of oxidized cellulose is described. 

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