Filaments and Fibers

In some cases, chiral resolution can be recognized by helical structure formation. A variety of helical filaments and fibers can be observed in the B7 phase, as shown in Fig. 10. The B7 phase is identified to be a polarization-modulated phase and the internal helical polarization modulation is responsible for the helix [15]. In contrast,... 

The range of products that can be made by extrusion is very large rods, pipes, hoses, sheets, films, profiles, filaments and fibers, wire coatings, etc. 

Drawing of filaments and fibers may result in an orientation of either or both polymer molecules and crystalline aggregates in the direction of draw. In crystalline aggregates, specimen drawing does not change the degree of crystallinity significantly. However, in amorphous or only partially crystallized material, crystallinity is likely to develop and increase. 

Filaments and fibers are one-dimensional forms of thermoplasts, or, less often, of thermosets, elastoplasts, or elastomers. They are classffled as natural or chemical flbers according to origin. 

The mechanical properties of filaments and fibers depend on the fiber diameter and length as well as on the chemical and physical structure (Fig. 38-13). The probability of a defect occurring increases, of course, with the length and diameter of the filament. Industrially produced filaments may have a maximum of one defect per 2000 km of filament. In contrast, fibers produced on a laboratory scale have many more defects. Consequently, when comparing the mechanical properties of laboratory scale fibers, the highest experimentally obtained values should always be used, since otherwise, the influence of the defects and not the structures are compared. The properties... 

It should be noted that the stress-strain curves of filaments and fibers are nonlinear even at smallest strains when comparing their mechanical properties. Such diagrams also show the characteristic behavioral differences between cotton and rayon which are not obvious from Table 38-2 (Figure 38-14). 

Ch(q>. 38 Filaments and Fibers Table 38-7. Typical Properties of Leather ... 

I wish to first acknowledge the important contributions to this work by my Washington State University colleagues, Les Jensen, Ahmad Jahan-Latibari, and Ed Donaldson. I also wish to thank those people who have contributed specimens used in these studies, particularly R. L. Moore, Lawrence Livermore Laboratory, for samples of filaments and fiber/epoxy strands, and A. N. Gent, Institute of Polymer Science, University of Akron, for all the polybutabiene samples. We are also appreciative of interest and advice from 0. Ishai, A. Gray, and L. C. Clements of NASA-Ames... 

Thennal processing Extmsion Rods, films, filaments and fibers... 

Mar76] Maringer, R.E., Mobley, C.E., and COLUNGS, E.W., An Experimental Method for the Casting of Rapidly Quenched Filament and Fibers, in Rapidly Quenched Metals, N.J. Grant and B.C. Giessen, Ed., Section 1, MIT Press, 1976, p. 29-36... 

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