Fibers drawing

Fig. 11. OVD process (a) soot deposition, (b) soot perform cross section, (c) preform sintering, and (d) fiber drawing.

Figure 7 SEM photographs of peeled back surfaces of PEI-TLCP blend fibers. Draw ratio is 4 (x 2000). The amount of PEsI in the blends are (A) 0 phr, (B) 0.75 phr, and (C) 3.75 phr. Source Ref. 11.

The parallelization of crystallites, occurring as a result of fiber drawing, which consists in assuming by crystallite axes-positions more or less mutually parallel, leads to the development of texture within the fiber. In the case of PET fibers, this is a specific texture, different from that of other kinds of chemical fibers. It is called axial-tilted texture. The occurrence of such a texture is proved by the displacement of x-ray reflexes of paratropic lattice planes in relation to the equator of the texture dif-fractogram and by the deviation from the rectilinear arrangement of oblique diffraction planes. With the preservation of the principle of rotational symmetry, the inclination of all the crystallites axes in relation to the fiber axis is a characteristic of such a type of texture. The angle formed by the axes of particular crystallites (the translation direction of space lattice [c]) and the... 

Other challenges in engineering chemical processes Effluent treatment Effluent treatment Fiber drawing and coating processes Ceramic processing... 

Acrylonitrile, H2 CCHCN, is used to manufacture polymers for synthetic fibers. Draw the Lewis structure of acrylonitrile. 

Fiber disposal, viscose process and, 11 279 Fiber draw tower, 11 143 Fiber drum and can packaging, converting, 18 22... 

Fiber glass-reinforced plastic tanks, 24 299 Fiber grating, 11 150-151 Fiber length (FL), 18 148 Fiber manufacture, sodium bisulfite in, 23 673 Fiber-matrix bonding, 26 771-772 Fiber modification, chemical, 16 14 Fibernodes, 11 595 Fiber-optic probes, 16 524 Fiber optics, 11 128-162, 15 469 attenuation in, 11 132-133 dispersion in, 11 134-135 fiber drawing in, 11 141-145 fiber strength in, 11 141-145 history of, 11 128-131 inside processes for, 11 136-140 near-infrared, 23 141 optical amplifiers with, 11 145-146 optical fiber fabrication for,... 

In the sol-gel process, ceramic polymer precursors are formed in solution at ambient temperature shaped by casting, film formation, or fiber drawing and then consolidated to furnish dense glasses or polycrystalline ceramics. The most common sol-gel procedures involve alkoxides of silicon, boron, titanium, and aluminum. In alcohol water solution, the alkoxide groups are removed stepwise by hydrolysis under acidic or basic catalysis and... 

Dacron Trade name for PET fiber, draw Depth of mold cavity. 

Figure 7.50 Schematic illustration of MCVD processing of optical fiber, including (a) tube setup, (b) deposition, (c) collapse, and (d) fiber drawing. Reprinted, by permission, from J. B. MacChesney, J. Mater. Ed., 11(14), 343 (1989). Copyright 1989 by Materials Research Laboratory.

Pig. 7. Collapsing and fiber drawing stages for optical fiber preparation Schematic drawing in reality the three stages follow one another in time... 

From a material point of view, amplification at 1.3 jum and up-conversion processes will benefit from the use of glasses with lower phonon energies than fluorides. As far as rare-earth spectroscopy is concerned, sulfide glasses are for the moment the most promising materials. However, significant improvements are still to be made with sulfides in terms of glass chemical purity and fiber drawing processes. 

Equation (7.3) states that the rate at which the fiber (or sheet) becomes thinner is proportional to the applied force, not the applied stress. This means that thinner and thicker regions suffer cross-sectional reduction at an equal rate. This expression also informs us that, for a given load, as the viscosity ri increases, the axial strain rate, e, decreases. This has very important implications in fiber drawing. In order to understand these implications, we need to examine the temperature dependence of viscosity. The temperature dependence of viscosity is given by the Eyring equation... 

Fiber drawing is carried out in the course of sol to gel conversion at viscosities greater than 1 Pas (1 Nm s). The gelled fibers are heated to obtain glass fibers. 

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