Textile fibers structure

Ansell, M. P. and L. Y. Mwaikambo, The Structure of Cotton and other Plant Fibers, in Handbook of Textile Fiber Structure, S. J. Eichhom, et al.. Editors. 2009, Wood-head Publishing. p. 62-94. 

By the addition of glass fibers, textile fibers, or chopped fabrics to crosslinkable polymers molding materials are produced with increased tensile strength, stiffness, and thermal stability compared to the filler-free polymers. The so-called reinforcing fillers, like carbon black, have good adhesion to the matrix due to their nonpolar structure and their characteristic geometry. 

Crystallinity and disorder are important structural parameters for understanding relationships between structure and physical properties. Flaws and distortions are the main features that limit the ultimate properties of textile fibers. Some of these crazes, cracks and voids are revealed under the electron microscope, either on the surface or in cross sections stained with heavy metals (J, 2). However, these staining techniques (that reveal the main morphological features) make it much more difficult to determine the degree of distortion of the crystalline fraction. Theoretically, line profile studies permit separation of effects due to crystalline size from those due to structural distortions. However, the lack of peaks in semicrystalline fiber x-ray patterns hinders that approach. 

These examples illustrate how to obtain results about crystallinity and disorder for a better understanding of the relationships between structure and properties. The reader is, however, cautioned that crystallinity and disorder parameters determined by x-ray diffractometry are average values and that they should be carefully compared with local order measured by electron diffraction on ultra-thin cross sections of textile fibers (9) with differing crystallite sizes (10,11). 

Cellulose is the main structural element of the cell walls of most plants and is also a major component of wood, as well as cotton and other textile fibers, such as linen and hemp. The history of cellulose is as old as that of humankind. For instance, fine clothes and cottons have been recovered from the tombs of the ancient kings of Egypt, the pharaohs. Today, cellulose and its derivatives are used in the industrial preparation of paper and also in the chemical industry as a stabilizer, dispersing agent, thickener, and gelling agent. Cellulose is also a component of dietary fiber. 

The two most common natural textile fibers encountered in modern fabrics have contrasting responses to soil burial. Under most soil burial conditions cellulose will degrade rapidly whereas wool will decay at a slower rate. These phenomena are demonstrated by the degradation of textile fibers from the Experimental Earthworks Project (Janaway 1996a). Figures 7.9 and 7.10 compare wool and linen buried in the chalk environments at Overton Down for 32 years. The linen is denatured to the point that there is little surviving morphology, whereas the wool retained some fiber structure. 

Acid dyes include metal-complexed azo structures, where the metals used are cobalt, chromium, and iron.10 Examples are 1 1 and 2 3 chromium complexes and 1 2 cobalt complexes, where the numbers employed represent the ratio of metal atoms to dye molecules. Metal-complexed dyes can be formed inside textile fibers by treating suitably dyed fibers with a solution containing metal ions.11 In this case, the metal-free forms of these azo dyes are known as mordant dyes and contain mainly ortho, ortho -bis-hydroxy or ortho-carboxy, ortho -hydroxy groups (e.g., C.I. Mordant Black 11, Mordant Yellow 8, and Mordant Orange 6). When the metal complexes are formed prior to the dye application process, the resultant dyes are known as... 

High performance polymer fibers (HPPF) have excellent mechanical properties compared to traditional textile fibers such as nylon. The typical HPPFs are aramid and polyethylene fibers (6). Aramid is a generic name for a class of aromatic polyamide fibers, most of which are varieties of poly(p-pheny-lene terephthalamide). Kevlar is the trade name of the varieties of aramid polymers introduced conunercially by Dupont. The molecules in the fibers of these materials are oriented in the axial direction. Poly(p-phenylene terephthalamide) is a rigid molecule with the following structure ... 

Reactive dyes were introduced at the end of the 1950s. These synthetic dyes consist of a two-part, direct coloring agent. The first moiety is a chro-mophore with an azo, anthraquinone, or phthalocya-nine derivative structure. This moiety is connected to a second reactive group, which is able to form covalent bonds with the amine or sulfhydryl groups of proteins in the textile fibers (Figure 21). The main... 

In 1949, a series of authoritative papers on the structure of textile fibers was published by the Textile Institute in the Proceedings section of Journal of the Textile Institute (85), Three of the papers are general and five deal with specific natural fibers. 

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