Cellulose Wadding

This is a loosely structured, highly absorbent fiber product. It is made from virgin fibers. Its use includes the production of sanitary towels, surgical artificial cotton, patients sheets, and packing cotton. 

Toilet paper (bathroom tissue) is the biggest single product made from tissue. It is made in one, two, three or five plys with or without moderate wet strength, because this type of tissue has to disintegrate in the sewage system. Toilet paper should be smooth and can be embossed, unprinted or patterned, tinted, purely white or off-white. 

Kitchen towels are the second biggest product for the consumer sector. Kitchen towels usually have a basis weight of 20-24 g m . Sheets are 220-280 mm wide and 250-280 mm long. The number of sheets to a roU is normally between 54 and 100. 

Most kitchen towels are two-ply. Good wet strength and high water absorbency behavior are the most important functionalities. 

Serviettes can be one-, two-, three- or four-ply. The size and type of fold vary greatly. 

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Cellulose wadding is produced from delignified wood pulp and manufactured in a multiple laminate material form. It is used in large pieces to absorb large volumes of fluid in incontinence but is not used in contact with a wound unless enclosed in an outer fabric sleeve to prevent fiber loss to the wound. 

Polysaccharides, such as cellulose and starch, can be oxidized with ozone and then converted to their formazans. A cellulose wad or a sample of starch powder, finely divided or suspended in water, was placed in a gas-washing bottle with a shrunken glass filter and ozonized at room temperature for 8 to 18 hours, carefully washed, and reacted in acetic acid with phenylhydrazine. This resulted in vividly yellow phenyl-hydrazones of the oxidized polysaccharides. By the reaction with an ice-cold solution of diazotized aniline in pyridine and ethyl alcohol, the bright red formazans of the ozone-oxidized polysaccharides were obtained. 

By regulating the rate of oxidation it is possible to determine how many formazan groups form per monosaccharide unit. For instance, in a cellulose wad oxidized as prescribed by Jajnne and Satre, for 120 hours, statistically every third monosaccharide is converted into a formazan and in a wad oxidized for four hours, every sixteenth monosaccharide. Provided that the rate of oxidation is not too high, the formazan obtained retains its original fibrous structure. The transformation into formazan can be regulated in all the other polysaccharides in the same way. With the soluble polysaccharides (for example, dextran), oxidation is a much quicker process. 

Yackel and Kenyon and Maurer and Reiff were the first to oxidize cellulose with nitrogen dioxide to obtain a poly(glycosiduronic acid). In addition to the principal reaction, their investigations pointed to the possibility of a number of side reactions. The formazan reaction revealed the presence of aldehyde groups in cellulose wads transformed to... 

Structure of the Cell Wall. The iaterior stmcture of the ceU wall is shown in Figure 6. The interfiber region is the middle lamella (ML). This region, rich in lignin, is amorphous and shows no fibnUar stmcture when examined under the electron microscope. The cell wall is composed of stmcturaHy different layers or lamellae, reflecting the manner in which the cell forms. The newly formed cell contains protoplasm, from which cellulose and the other cell wall polymers are laid down to thicken the cell wall internally. Thus, there is a primary wall (P) and a secondary wall (S). The secondary wall is subdivided into three portions, the S, S2, and layers, which form sequentially toward the lumen. Viewed from the lumen, the cell wall frequendy has a bumpy appearance. This is called the warty layer and is composed of protoplasmic debris. The warty layer and exposed layer are sometimes referred to as the tertiary wad. 

Magnesium perchlorate contained in a glass tube between wads of cotton wool was used to dry a mixture of oxygen and dinitrogen tetraoxide. After several days the drying tube exploded violently. It seems probable that the acidic fumes and cotton produced cellulose nitrate, aided by the dehydrating action of the perchlorate. 

Humidity. If the humidity of the packaging area is higher than that of the storage area, condensation may form on the containers, wads, or closures, and any cellulose-based materials will begin to absorb moisture. It may take days (even weeks in the case of roll materials) to reach equilibrium with the filling area. 

Woven cloth, cotton wadding, cellulose fiber batt, papers, and foamed polyurethane have been used as traditional absorbent materials for water. These materials can absorb 1-20 g of water per gram material and the water absorbed is easily removed from the materials by applying low pressure. In recent years, superabsorbent polymers, which can absorb up to 1000 g of water per gram of polymer and up to about 100 g of dilute salt solution per gram of polymer and the water absorbed can hardly be removed from the polymers even by applying high pressure, have been prepared and commercially used in many applications. 

Dimethyl phthalate and diethyl phthalate are traditional plasticisers for cellulose acetate, but due to their high volatility, triphenyl phosphate (TPP) is preferred for applications where permanence is important. TPP also improves the flame retardance of cellulose acetate and is generally used in conjunction with dimethoxyethyl phthalate to improve the melt flow properties of the compound. Dimethoxyethyl phthalate is also used as a bonding agent for cellulose acetate fibre waddings. About 5-15% of the plasticiser is sprayed on to the matted fibre which is then bonded at approximately 175°C to produce a non-woven fabric. 

Transfer the eaiqple on a wad of dry cellulose pulp to the top of the prepared alumina-cellulose column and extract the uranium with 200 to 250 ml of ether-nltrlo acid solvent if arsenic or molybdenum and arsenic Is present In the original saaqple. If molybdenum alone Is present, the anount of solvent can be reduced to I50 ml. Screen the column from direct sunlight. After removal of ether from the eluate, determine the uranium volune-trlcally.i ... 

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