A cellulose acetate

Details Dreyfus brothers begun experimental work on the development of cellulose acetate in 1904. In 1910 they opened a factory capable to produce 3 tons of cellulose acetate per day, mainly used as base for motion picture film and lacquer also used by growing aircraft industry for fabric coatings for wings and fuselage covering  

Formulation example - oellulose/acetlo anhydride ratio = 3.43-10.29 Daud, W R W Djuned, F M. Carbohydrate Polym., 132, 252-60,2015. 

Method of synthesis oellulose derived from wood pulp is reacted with acetic anhydride In the presence of sulfuric acid, followed by the oontrolled partial hydrolysis in which sulfuric acid and some acetic acid groups are removed to achieve required degree of acetylation  

Mass average molecular weight, dalton, g/ 45,000-237,000 Rscher, S Thuemmler, K Volkert, 

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Cellit, n. cellite (a cellulose acetate), cellonieren, v.t. treat with Cellon-Lack. Cellon-Lack, m. a cellulose acetate Lacquer. T. N. 

The enzyme is used in an enzyme electrode in which a tube is sealed at its lower end with a cellulose acetate membrane. An outer membrane of collagen is also attached to the end of the electrode tube and glucose oxidase enzyme is contained in the space between the two diaphragms. 

Figure 50-2. Technique of cellulose acetate zone electrophoresis. A A small amount of serum or other fluid is applied to a cellulose acetate strip. B Electrophoresis of sample in electrolyte buffer is performed.

The literature reports various (multidimensional) chromatographic approaches involving SEC and LC operating on dissolved polymer/additive mixtures. Floyd [985] has used microbore (1 mm i.d.) SEC-RPLC for the quantitative analysis of Tinuvin P in a cellulose acetate solution in THF, after separation of the polymeric and additive fractions total analysis time about 30 min. Relative accuracy and precision of 3 % and 1.5% were quoted. SEC-RPLC was also used to determine the styrene level in polystyrene crystals [986]. Additives in copolymers have been separated in a SEC/C system [987]. Chlorohydrin mixtures may be analysed by RPLC, but not in the presence of polymer. Thus, SEC... 

The process flowsheet for a cellulose acetate fibers process is shown in Figure 19.12. Solvent is removed from the fibers in a dryer by recirculating air. The air is cooled before it enters an absorber where the solvent is absorbed in water. The solvent-water mixture is separated in a distillation column and... 

Figure II. Effect of film casting conditions on the performance of resulting (a) cellulose acetate (12) and (h) aromatic polyamide-hydrazide membranes. The latter data are tho.se of O. Kutowy and S. Sourirafan (not yet published).

Membrane Specifications. At a specified operating temperature and pressure, a cellulose acetate membrane is completely specified in terms of its pure water permeability constant A and solute transport parameter D /k6 for a convenient reference solute such as sodium chloride. A single set of experimental data on (PWP), (PR), and f at known operating conditions is enough to obtain data on the specifying parameters A and (DAM/X6)jjg(. 2 at any given temperature and pressure. 

Using eq 11, 14, 15, 16 and 17, one can for example calculate the effect of feed concentration and feed flow rate on f and (PR) for NaCl-H20 feed solutions obtainable with a cellulose acetate membrane specified in terms of A and (DAM NaCl ... 

This presentation will discuss the membrane performance and its physical and chemical changes under unfavourable conditions. This kind of studies will give us information on trouble-shooting counter-measures for unexpected membrane deteriorations, and on the durability of a cellulose acetate membrane under adverse conditions. 

DNA modification of a commercial carbon ink without any electrochemical preconditioning by dry-adsorption was also reported. The surface was modified by covering with dsDNA solution and leaving the electrode to dry overnight. A stable, thin (about 100 p,m) DNA layer was obtained [111, 112]. The dsDNA was also demonstrated to be stably adsorbed when entrapped in a cellulose-acetate-based film on the surface of a carbon-based ink [113]. 

For acid-labile drugs, a coating of wax or of a cellulose acetate polymer is used to prevent disintegration of solid dosage forms in the stomach. Accordingly, disintegration and dissolution will take place in the duodenum at normal speed (A, track 1) and drug liberation per se is not retarded. 

Several amperometric immunosensors have been developed for monoclonal antibodies (IgG), a-interferon and the pesticide 2,4-dichlorophenoxy-acetic acid (2,4-D) by using a flow-cell with the catching antibody covalently bound to a cellulose acetate or activated nylon membrane as shown in Fig. 3.31. B. With multiepitope antigens (e.g. a protein), after the antigen is bound and washed, a second enzyme-labelled antibody is used to form a sandwich... 

Several variants of the biosensor in Scheme 5 have been proposed. One is a CPE containing at its tip a paste of graphite powder loaded with HRP and ferrocene ([Cp Fe(II) Cp]) mediator, which is further covered with a cellulose acetate film coated with Nafion. The biosensor is mounted on a FIA system in a three-electrode setup, as working electrode at a potential of 4-100 mV vs. SCSE and a Pt counterelectrode. The LOD (SNR 6) for H2O2 is 200 fmol (20 p,L injection of 10 nM solution), with linearity up to 25 In... 

TABLE 3.7 Effects on viable counts of contact with a cellulose acetate coating containing toluidine blue and rose bengal and exposed to light from a 25-W fluorescent lamp (adapted from Decraene et at., 2006)... 

Figure 5.67 Influence of temperature on the stress-strain response of (a) cellulose acetate and (b) poly(methyl methacrylate). Reprinted, by permission, from J. M. G. Cowie, Polymers Chemistry Physics of Modem Materials, 2nd ed., p. 283. Copyright 1991 by J. M. G. Cowie.

The choice of material for use as inhibitor depends mainly upon the type of propellant, that is, DB, CMDB, Composite and Fuel-rich and also on the ingredients in their formulations. For double-base propellants, cellulosic materials such a cellulose acetate, ethyl cellulose and different filled or unfilled flexible polyesters are used while fuel or binder material filled with inert substances such as asbestos, mica, silica, etc. in fine powder form is used for composite propellants. Since nitroglycerine is present in CMDB propellants also as in DB propellants, the materials used for DB propellants may also be used with minor modifications for the inhibition of CMDB propellants. 

In reverse osmosis both solvent and solute diffuse because of gradients in their chemical potentials. For the solvent there is no gradient of chemical potential at an osmotic pressure of x at applied pressures p greater than 7r, there is such a gradient that is proportional to the difference p — ir. To a first approximation, the gradient of the solute chemical potential is independent of p and depends on the difference between concentrations on opposite sides of the membrane. This leads to the result that the fraction of solute retained varies as [1 + const./(p — 7r)] 1. Verify that the following data for a reverse osmosis experiment with 0.1 M NaCl and a cellulose acetate membrane follow this relationship ... 

Fig. 5. Intrinsic viscosity of a cellulose acetate graft copolymer (44.1% combined polystyrene) and the corresponding homopoly-mers in toluene-acetone mixtures...

It has already been implied that cellulose triacetate will not produce a thermoplastic, as its softening point cannot be reduced appreciably by plasticizers. It is used in solution processes, however, to produce films and libers. Triacetate films absorb less water than films of secondary cellulose acetate, and they arc therefore more dimensionally stable in environments where the humidity is not controlled. Triacetate fibers, with a similar resistance to water, impart to fabrics wrinkle resistance, dimensional stability, and the ability to dry rapidly. Under United Slates federal regulations, a filler must tic made from a cellulose acetate having... 

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