Cellulose triacetate properties

The predominant cellulose ester fiber is cellulose acetate, a partially acetylated cellulose, also called acetate or secondary acetate. It is widely used in textiles because of its attractive economics, bright color, styling versatiUty, and other favorable aesthetic properties. However, its largest commercial appHcation is as the fibrous material in cigarette filters, where its smoke removal properties and contribution to taste make it the standard for the cigarette industry. Cellulose triacetate fiber, also known as primary cellulose acetate, is an almost completely acetylated cellulose. Although it has fiber properties that are different, and in many ways better than cellulose acetate, it is of lower commercial significance primarily because of environmental considerations in fiber preparation. 

The cellulose esters with the largest commercial consumption are cellulose acetate, including cellulose triacetate, cellulose acetate butyrate, and cellulose acetate propionate. Cellulose acetate is used in textile fibers, plastics, film, sheeting, and lacquers. The cellulose acetate used for photographic film base is almost exclusively triacetate some triacetate is also used for textile fibers because of its crystalline and heat-setting characteristics. The critical properties of cellulose acetate as related to appHcation are given in Table 10. 

Permeability Properties of Cellulose Triacetate Hollow-Fiber Membranes for One-Pass Seawater Desalination... 

The prime object of the present study was to determine the compositional polydlspersity of commercial cellulose triacetate and to examine the effect of molecular weight and molecular weight distribution on the mechanical properties of the fibres. 

Tetraethylene glycol may be used direcdy as a plasticizer or modified by esterification with fatty acids to produce plasticizers (qv). Tetraethylene glycol is used direcdy to plasticize separation membranes, such as silicone mbber, poly(vinyl acetate), and cellulose triacetate. Ceramic materials utilize tetraethylene glycol as plasticizing agents in resistant refractory plastics and molded ceramics. It is also employed to improve the physical properties of cyanoacrylate and polyacrylonitrile adhesives, and is chemically modified to form polyisocyanate, polymethacrylate, and to contain silicone compounds used for adhesives. 

The properties of partially acetylated cellulose for the separation of enantiomers were recognized in 1966 by Luttringhaus and Peters [14]. But the full potential of cellulose acetate was developed by Hesse and Hagel in 1973 [15]. Since then, this stationary phase has been frequently used for the resolution of various racemic compounds. Native cellulose acetylated heterogeneously yields a crystallographic form of cellulose triacetate (CTA) known as CTA-I, which corresponds to its source, an indication that the original supramolecular structure of the starting... 

The first major application of microfiltration membranes was for biological testing of water. This remains an important laboratory application in microbiology and biotechnology. For these applications the early cellulose acetate/cellulose nitrate phase separation membranes made by vapor-phase precipitation with water are still widely used. In the early 1960s and 1970s, a number of other membrane materials with improved mechanical properties and chemical stability were developed. These include polyacrylonitrile-poly(vinyl chloride) copolymers, poly(vinylidene fluoride), polysulfone, cellulose triacetate, and various nylons. Most cartridge filters use these membranes. More recently poly(tetrafluo-roethylene) membranes have come into use. 

Report of Committee Dyeing Properties of Disperse Dyes, I Cellulose Acetate, J. Soc. Dyers Colour. 80 (1964) 237-242, II Cellulose Triacetate, 81 (1965) 209-210 J.-H. Choi, A.D. Towns, Color Technol. 117 (2001), 127-133. 

A summary of the properties of some of these materials is presented in Tables 8 and 9. Diffusion coefficients and NaCl partition coefficients are presented in Table 8 for cellulose triacetate and for Nomex K>lyamide. In most cases, however, intrinsic transport properties are not known, and what is reported in the literature is the water flux and salt rejection of RO membranes under given test conditions. Under comparable test conditions (0.5-1% NaCl, 27—68 atm) the water fluxes of these newer membranes are comparable (0.4-0.8 m /m -day). Salt rejection data are presented in Table 9. To put these data in perspective, the salt rejection of cellulose 2.5-acetate membranes is typically <99%. However, for various reasons none of these new membranes has yet become commercially important. 

In general, the properties of these amylose triacetate films are very similar to those of cellulose triacetate films. A comparison of some of their properties is given in Table II. 

Wolf, R. M., Erancotte, E., Lohmann, D., Quantitative correlation between calculated molecular properties and retention of series of structurally related racemats on cellulose triacetate, J.Chem. Soc., Perkins Trans. II, 1988, 893-901. 

A similar series of tests for the assessment of the dyeing properties of Disperse Dyes on cellulose triacetate has been published J.S.D.C., 1965, 81, 209). 

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