Cellulose triacetate Applications

Some acetate ester is recovered at the completion of reaction and marketed as commercial cellulose triacetate it has a DS very close lu. V Other tricsters have found no commercial applications. 

FIBERS CELLULOSE ESTERS. The predominant cellulose esier liber 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 versatility, and other favorable aesthetic properties. However, its largest commercial application is as the fibrous material in cigarette filters, where its smoke removal properties and contribution to taste make II 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 belter than cellulose acetate, it is uf lower commercial significance primarily because of environmental considerations in fiber preparation. 

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. 

Disperse dyes are currently used to dye cellulose 2.5-acetate, cellulose triacetate, synthetic polyamides, and to a lesser degree, polyacrylonitrile and polypropylene. Their major application is clearly for dyeing polyesters. 

Currently, Toyobo markets the Hollosep cellulose triacetate hollow fine fiber for RO applications (Hollosep is a registered trademark of Toyobo Company, Ltd, Osaka, Japan). 

The color of cellulose acetate dyed with some disperse dyes is subject to gas fading. Treatment of the dyed material with diethanolamine or melamine can overcome the problem (3). Similarly, with cellulose triacetate, gas fading of dyes can occur. It has been stated that protection can be obtained by the application of an inhibitor (3). 

Most MF, UF, RO, and NF membranes are synthetic organic polymers. NF membranes are made from cellulose acetate blends, cellulose triacetate (CTA), or polyamide composites such as the RO membranes, or they could be modified forms of UF membranes such as sulfonated polysulfone [27]. On the other hand, poly(vinyl alcohol) (PVA) is a significant polymer for nonaqueous applications. Chemical stmctures of a few of the prominent polymers are shown in Figure 42.4. 

Amylose triacetate prepared from butanol-precipitated starch may be plasticized with almost any of the common plasticizers which are applicable to the plasticization of cellulose triacetate. For example, some suitable plasticizers are dimethyl or diethyl tartrate, tributyl citrate, tributyl phosphate, tricresyl phosphate, polyethylene glycol, and pentaerythritol tetraacetate. Addition of only 10-20% plasticizer is sufficient to give amylose triacetate films a useful and lasting degree of... 

Applications of the polymer inclusion membranes in the waste-water treatment have so far been limited to the radioactive wastewaters. Kusumocahyo et al. [158] reported the application of a polymer inclusion membrane to removal of Ce(NO3)3 from wastewater with low radioactivity. The membrane was composed of cellulose triacetate (the base polymer),... 

The functional stability of GOD membranes has also been enhanced by coupling with an asymmetric ultrafiltration membrane (Koyama et al., 1980). The GOD-cellulose acetate membrane used was prepared as follows 250 mg cellulose triacetate was dissolved in 5 ml dichloro-methane, the solution was mixed with 0.2 ml 50% glutaraldehyde and 1 ml l,8-diamino-4-amino methyl octane and sprayed onto a glass plate. After three days the membrane was removed from the support and immersed in 1% glutaraldehyde solution for 1 h at 35°C, rinsed with water and exposed for 2-3 h to phosphate buffer, pH 7.7, containing 1 mg/ml GOD. The membrane was then treated with sodium tetraborate, rinsed with water and stored at 4-lO°C until use. It was combined with the ultrafiltration membrane in the following way 20 mg cellulose diacetate was dissolved in 35 g formamide and 45 g acetone and cast on a glass plate. At room temperature the solvents evaporated within a few seconds and a membrane of about 30 pm thickness remained, which was kept in ice water for 1 h before application in the sensor. 

Sheeting and films of cellulose triacetate are used in the production of visual aids, graphic arts, greeting cards, photographic albums, and protective folders. Cellulose triacetate is extensively used for photographic, x-ray, and cinematographic films. In these applications cellulose triacetate has displaced celluloid mainly because the triacetate does not have the great inflammability of celluloid. 

Cellulose triacetate offers the unique combination of ease-of-care and esthetic properties. A particularly important application of triacetate is in surface-finished fabrics such as fleece, velour, and suede-like fabrics for robes and dresses. These fabrics offer superb esthetic qualities at reasonable cost. Triacetate is also desirable for print fabrics, as it produces bright, sharp colors [15]. 

High-tenacity fibers have been demonstrated by dry-jet wet-spinning of anisotropic solutions of cellulose triacetate, but a product has not yet been commercialized [113,114], Nanofiber composites have been demonstrated by electro-spinning dilute cellulose acetate and triacetate solutions. These composites have exceptionally high specific surface area, and exciting new applications are envisioned [115], There are many new specialty applications, and research is continually finding new applications that take advantage of the unique balance of properties of cellulose acetate [107,109,110,116],... 

Bayou, N., Arous, O., Amara, M., and Kerdjoudj, H. 2010. Elaboration and characterisation of a plasticized cellulose triacetate membrane containing trioctylphosphine oxide (TOPO) Application to the transport of uranium and molybdenum ions. Comptes Rendus Chimie 13 1370-1376. 

NATCO reports the use of hollow fibre bundles of cellulose triacetate in an EOR application in Texas (USA) at a scale 100MMSCFD (3 OOOOOOmVday) of gas since 1994 [14], Pre-treatment includes chilling to remove heavy hydrocarbons and then dehydration by silica gel beds. An expansion of this facility to 200MMSCFD (6000000mVday) was planned in 2005. 

Hydroxyl groups present on 2, 3, and 6 positiOTis are the sites where derivatization can be carried out. Cellulose esters and ethers are the most important commercial materials. Among the esters, cellulose acetate and cellulose triacetate are film- and fiber-forming materials and have wide range of applications. The inorganic ester nitrocellulose was initially used as an explosive and as a film-forming material. 

---