Cellulose development

Bacterial Cellulose. Development of a new strain of Acetobacter may lead to economical production of another novel ceUulose. CeUulon fiber has a very fine fiber diameter and therefore a much larger surface area, which makes it physicaUy distinct from wood ceUulose. Its physical properties mote closely resemble those of the microcrystalline ceUuloses thus it feels smooth ia the mouth, has a high water-binding capacity, and provides viscous aqueous dispersions at low concentration. It iateracts synergisticaUy with xanthan and CMC for enhanced viscosity and stabUity. 

Aaronson, Evaluate Method of Nitrating Cellulose Developed by the Stein Hall Co , PATR 1331 (1943) 3) W. Latimer J. Hildebrand,... 

Thin films of the solutions between microscope slides were sheared by applying even pressure on a coverslip while sliding it approximately one cm. The anisotropy appeared to increase as measured by increases in the birefiingence. Solutions containing 10-16% (w/w) cellulose developed a threaded texture and the mesophases were stable with time and oriented in the direction of shear. These observations, while not definitive, suggested a cholesteric to nematic transition occurred on shearing. 

Adsorption systems are governed by adsorption rather than a partition mechanism. Compounds adsorbed by cellulose may be separated on unmodified cellulose developed with water or salt solutions [33]. Compounds adsorbed by adsorbents such as silica or alumina are separated on papers impregnated with these adsorbents and developed with organic solvents. 

Pierre-Antoine F, Francois B, Rachida Z. Crosslinked cellulose developed by CuAAC, a route to new materials. Carbohydr Res. 2012 356 247-51. 

Tables R( Values and Limits of Detection of Anions Achieved on Layers of Microcrystalline Cellulose Developed with 0.1 M HCI-Acetone (1 9)...

Figure 2 Chromatography of Fraction 3 on carboxymethyl cellulose. Development of a column 2 x 92 cm was by stepwise elution with disodium succinate-acetic acid buffer at a flow rate of 60 ml per hour. The molar concentrations of sodium succinate to acetic acid are given at the top of the graph. Fraction 4 gave an identical elution pattern. Subfractions A - G were collected as indicated by the arrows.

Americans experience with cellulose developed a related... 

The two procedures primarily used for continuous nitration are the semicontinuous method developed by Bofors-Nobel Chematur of Sweden and the continuous method of Hercules Powder Co. in the United States. The latter process, which uses a multiple cascade system for nitration and a continuous wringing operation, increases safety, reduces the personnel involved, provides a substantial reduction in pollutants, and increases the uniformity of the product. The cellulose is automatically and continuously fed into the first of a series of pots at a controlled rate. It falls into the slurry of acid and nitrocellulose and is submerged immediately by a turbine-type agitator. The acid is deflvered to the pots from tanks at a rate controlled by appropriate instmmentation based on the desired acid to cellulose ratio. The slurry flows successively by gravity from the first to the last of the nitration vessels through under- and overflow weirs to ensure adequate retention time during nitration. The overflow from the last pot is fully nitrated cellulose. 

Carbon disulfide [75-15-0] is a clear colorless liquid that boils at 46°C, and should ideally be free of hydrogen sulfide and carbonyl sulfide. The reaction with alkaU cellulose is carried out either in a few large cylindrical vessels known as wet chums, or in many smaller hexagonal vessels known as dry chums. In the fully continuous viscose process, a Continuous Belt Xanthator, first developed by Du Pont, is used (15). 

The Finnish viscose producer Kemira Oy Saeteri collaborated with Neste Oy on the development of a carbamate derivative route. This system is based on work (89) that showed that the reaction between cellulose and urea gives a derivative easily dissolved in dilute sodium hydroxide ... 

Phosphoric Acid-Based Systems for Cellulosics. Semidurable flame-retardant treatments for cotton (qv) or wood (qv) can be attained by phosphorylation of cellulose, preferably in the presence of a nitrogenous compound. Commercial leach-resistant flame-retardant treatments for wood have been developed based on a reaction product of phosphoric acid with urea—formaldehyde and dicyandiamide resins (59,60). 

Dyes. In contrast to benzotrifluorides and fluoropyrknidines, limited commercialization has developed for dyes containing a fluoroaromatic group. FluorophenyUiydrazines have been converted to (fluorophenyl)pyrazolones, which are disperse dyes for cellulose acetate and nylon (192). 

Membrane modules have found extensive commercial appHcation in areas where medium purity hydrogen is required, as in ammonia purge streams (191). The first polymer membrane system was developed by Du Pont in the early 1970s. The membranes are typically made of aromatic polyaramide, polyimide, polysulfone, and cellulose acetate supported as spiral-wound hoUow-ftber modules (see Hollow-FIBERMEMBRANEs). 

Reverse Osmosis. This was the first membrane-based separation process to be commercialized on a significant scale. The breakthrough discovery that made reverse osmosis (qv) possible was the development of the Loeb-Sourirajan asymmetric cellulose acetate membrane. This membrane made desalination by reverse osmosis practical within a few years commercial plants were installed. The total worldwide market for reverse osmosis membrane modules is about 200 million /yr, spHt approximately between 25% hoUow-ftber and 75% spiral-wound modules. The general trend of the industry is toward spiral-wound modules for this appHcation, and the market share of the hoUow-ftber products is gradually falling (72). 

The first reverse osmosis modules made from cellulose diacetate had a salt rejection of approximately 97—98%. This was enough to produce potable water (ie, water containing less than 500 ppm salt) from brackish water sources, but was not enough to desalinate seawater efficiently. In the 1970s, interfacial composite membranes with salt rejections greater than 99.5% were developed, making seawater desalination possible (29,30) a number of large plants are in operation worldwide. 

Phloroglucinol is Hsted in the Colourindex as Cl Developer 19. It is particularly valuable in the dyeing of acetate fiber but also has been used as a coupler for azoic colors in viscose, Odon, cotton (qv), rayon, or nylon fibers, or in union fabrics containing these fibers (157). For example, cellulose acetate fabric is treated with an aromatic amine such as (9-dianisidine or a disperse dye such as A-hydroxyphenylazo-2-naphthylamine and the amine diazotizes on the fiber the fabric is then rinsed, freed of excess nitrite, and the azo color is developed in a phloroglucinol bath at pH 5—7. Depending on the diazo precursor used, intense blue to jet-black shades can be obtained with excellent light-, bleach-, and mbfastness. 

---