Cellulose-based fibers

Powdered resins systems (80-600 mesh) typically operate at lower pressure drops, generate less waste water, take up less space, and cost much less when compared to deep-bed polishers. However, they operate at only 3 to 4 gpm sq ft (although the filter element area is large) and are designed to be disposable, so that the powdered resin must be replaced whenever the bed is reconditioned. Sometimes inert resins or cellulose-based fibers are used either in place of powdered resins or as a premix, where they function as both filter aids and absorbents. 

The application of water-repellent finishes to fabrics actually involves a chemical reaction between the material and the finish. Cellulose-based fibers such as cotton possess hydroxyl (-OH) groups that exist on the surface of fabrics spun and woven from the fiber. The basic structure of cellulose portrayed in Fig. 7.6.1 reveals... 

Of this amount, about one half is used to produce raw materials from petrochemicals, with the other half used for energy to convert trees to wood pulp for cellulose-based fibers and to convert the wood pulp and petrochemical-derived raw materials to fibers. 

Bledzki, A. Gassan, J. Composites reinforced with cellulose based fibers. Prog. Polym. Sci. 1999, 24, 221-274. 

Dyes 8-12 belong to the family of azo conqiounds, while 13 is a formazan dye. Formazan dyes are more commonly used as dyes for cellulose-based fibers, in which case they would contain a reactive moiety, and are 1 1 Cu-complexed dyes (1 metal per dye molecule) (6). Metal complexes of the 1 2 type (1 metal per 2 dye molecules) are used for polyamide and protein fibers. In the latter case, Cr and Co complexes... 

Fillers and reinforcing fibers 7 and 8 Engineering-type applications for POs (especially PP and TPO), more interest in sustainable fillers and fibers Greater use of cellulose-based fiber reinforcements, of long-glass fiber reinforcement, and of nanofillers and specially fillers... 

In this chapter, the discussion is focused on the research on cellulose-based polymer composites conducted in some tropical countries in Southeast Asia. Southeast Asia is a subregion of Asia located in the tropical zone, where a variety of plants grow. Hence, there is a high availability of cellulose-based materials found in this area. This situation enhances the attractiveness of research on cellulose-based composites. The reported findings of researchers in Southeast Asia about the processing, properties and apphcation of composites made of commonlyused cellulose-based fibers such as sisal, flax, hemp, ramie, jute, kenaf, etc., are discussed along with many kinds of cellulose-based fibers of interest which have not been reported elsewhere. This chapter is a combination of reviews on some unique ceUulose-based polymer composites in Southeast Asia together with a report on the research conducted by the authors. 

Synthetic fiber (man-made fiber) n. A class name for various fibers (including filaments), distinguished from natural fibers such as wool and cotton, produced from fiber-forming substances which may be (1) Modified or transformed natural polymer, e.g., alginic and cellulose-based fibers such as acetates and rayon s. (2) Polymers synthesized from chemical compounds, e.g., acrylic, nylon, polyester, polyurethane, polyethylene, polyvinyl, and carbon/graphite fibers. (3) Fibers of mineral origin, e.g., glass, quartz, boron, and alumina. 

Fiber-reinforced structural composites are widely found in namre and include such diverse materials as bamboo, flax, and hemp (which contain long cellulose-based fibers) and hooves, fingernails, and rhinocerous bom, which contain long fibers of the protein keratin. Filled composites also occur in nature, the most obvious examples being the composite rock type known as breccias and fossil-containing shale and limestone. Sintered limestone is used to produce Pordand cement for the production of the filled composite known as concrete. 

The first carbonization of cellulose-based fibers dates back to Thomas Edison, who carbonized a natural cellulose filament for use as an incandescent lamp filament. In the mid-1950s, the Carbon Wool Corporation introduced the first commercial carbonized rayon fibers (79). PAN- and pitch-based carbon fibers have replaced rayon-based fibers in most high performance applications however, they continue to find use as ablative materials in missile nosecones and heat shielding (16). Additionally, the combination of low cost, ease of handling, and high natural porosity makes rayon an attractive precursor for activated carbon fibers (see CELLULOSE Fibers, Regenerated). 

Compound is immobilized on a cellulose-based fiber substrate." The fiber substrate filters the blood so that only the serum interacts with 1, The higher the concentration of Na" " in serum, the higher the fraction of 1 Na" ". This form is fluorescent, whereas 1 itself is significantly less fluorescent. The fluorescence intensity then produces, with appropriate calibration, the blood Na+ level. 

Cellulose is the most abundant biopolymer on earth. It can be used in different applications, namely in the form of fibers, and cellulose can be converted into numerous cellulose derivatives. Cellulose micro- and nanofibers have been the subject of intense research in the field of composites. Cellulose derivatives can show liquid crystalline chiral nematic phases, which can be used for the production of diverse composite systems. All-cellulosic composites based on liquid crystalline cellulosic matrices reinforced by cellulose micro- and nanofibers can show enhanced mechanical properties due to fiber orientation induced by the liquid crystalline matrix. Cellulose-based fibers electrospun from liquid crystalline phases can develop different structures, which are able to mimic the shape of plant tendrils on the nano- and microscale, opening new horizons for ceDulosic membrane applications. 

Dave V, Glasser WG (1997) Cellulose-based fibers from Uquid crystalline solutions 5 Processing and morphology of CAB blends with Ugnin. Polymer 38 2121-2126... 

Cellulose-Based Fibers—Cotton, Ramie, and Hemp... 

Cellulose is not water-soluble but is strongly hydrophilic. This property is responsible for the great comfort exhibited by cellulose-based fibers and by the corresponding fabrics. Under normal conditions of use, cellulose may contain up to 70% of loosely bound water. The partial replacement of polymer-polymer interactions by hydrogen bonds between cellulose and water causes a plasticization of the resulting material and thus a lowering of its mechanical characteristics. 

The great importance of manufactured fibers in the chemical industry and in the overall economy of the United States becomes apparent when the volume of production of these materials is considered and compared with the market value of even the least expensive of the raw materials used by them. The amounts of oil and natural gas consumed by the manufactured fiber industry represent around one percent of national annual usage. Of this amount, about one-half is used to produce raw materials from petrochemicals, with the other half used for energy to convert trees to wood pulp for cellulose-based fibers and to convert the wood pulp and petrochemical-derived raw materials to fibers. 

With the development of electrospinning, potential submicro- and nano-scale cellulose fiber is expected to bring valuable properties and expand the uses of cellulose based fibers significantly. However, the electrospiiming of cellulose encounters the same difficulty as conventional spuming the dissolution of cellulose. The same strategies (i.e. derivatization and direct solvents) have been taken by researchers. 

Dave, V. Glasser, W. G. (1993). Cellulose-based fibers from liquid crystalline solutions. III. Processing and morphology of cellulose and cellulose hexanoate esters. 

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