Industrial desirable characteristics from

Basically, the fibers grab oxygen molecules from the air so that their atomic binding pattern is reorganized. In the industry, this stage is performed with the use of a number of different techniques. In some cases, the oven is divided into a number of chambers, each with different temperatures the speed at which the fibers enter and exit the chambers can also be controlled depending on the desired characteristics of the fibers [10]. In other methods. 

Thermal fractionation technology is most developed in the palm oil industry, where most oils are fractionated before sales. Solids profiles of stearins that have been fractionated from crude palm oil by chilling to different temperatures are shown in Fig. 34.21.118 Thermal fractionation, and double fractionation can be useful tools in obtaining fat fractions with the specific desired characteristics (Fig. 34.22).119... 

The catalytic importance of zeolites from an industrial standpoint resides both in the ability to subtly tailor their properties to described characteristics and in the consequent high activities and selectivities( l). These last two attributes are primarily a result of the large internal surface area of the zeolites and their microporosity, respectively. The aspect of tailoring zeolites to desired characteristics demands an intimate knowledge of both their structural and chemical properties. 

Fundamental concepts of starch chemistry provide an interpretation of its function and behavior in various food uses. The characteristics of modified starches depend on granule structure and on specific size and shape of the component molecules. Most native starches contain both linear and branched polysaccharides. The linear fraction is responsible for gel formation and for various retrogradation effects, the branched fraction for high colloidal stability and good suspending qualities. Starches are employed in the food industry as gel formers, thickening agents, and colloidal emulsifiers. Desired characteristics can frequently be enhanced by choice of an appropriate modified starch. The various food uses are individually discussed from the standpoint of molecular behavior and optimal types of modification. 

Other Additives With the growing importance of size enlargement by agglomeration for the manufacturing of engineered products (see also Chapter 12), many other additives are used as functional components. Particularly in the food industry (Fig. 5.12), but also in other, by the public less well known applications, materials with specific, predetermined, and controlled properties are formulated from particulate ingredients and then agglomerated to yield consumer products that feature desirable characteristics. 

The chemical industry s interest in polymers dates back to the 19th century. In those days it was a case of synthetically modifying natural polymers with chemical reagents to either improve their properties or produce new materials with desirable characteristics. Notable examples were nitration of cellulose giving the explosive nitrocellulose, production of regenerated cellulose (rayon or artificial silk) via its xanthate derivative, and vulcanization of rubber by heating with sulphur. Manufacture of acetylated cellulose (cellulose acetate or acetate rayon) developed rapidly from 1914 onwards with its use both as a semi-synthetic fibre and as a thermoplastic material for extrusion as a film. 

HoUow fibers can be prepared from almost any spiunable material. The fiber can be spun directly as a membrane or as a substrate which is post-treated to achieve desired membrane characteristics. Analogous fibers have been spun in the textile industry and are employed for the production of high bulk, low density fabrics. The technology employed in the fabrication of synthetic fibers appUes also to the spinning of hoUow-fiber membranes from natural and synthetic polymers. 

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