Fibre Characteristics

1 Mid-twentieth century soya bean protein fibres 

Despite this superficial resemblance, soya bean protein fibres had lower wet and dry strength and elasticity than wool (see Table 13.3). All midtwentieth century manufacturers experienced problems with the low tensile strength and poor wet strength of soya bean fibres. Sherman and Sherman stated that its wet strength [was] so inferior as to constitute a distinct handicap . Dry soya bean fibre had a tensile strength of about 55% that of 

Property Soya bean Casein milk fibre Wool Silk (degummed) Nylon 

Residual elongation, dry (%) Fibre broke 15.5 12.0 Fibre broke Not tested 

Load at 20% elongation, dry Fibre broke before 0.44% 0.72% Fibre broke before Not tested 

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Graded index stmctures allow greater control over fibre characteristics. In these stmctures, the core has a variable... 

In further work on nylon [145], this trifunctional reactant was applied simultaneously with various nucleophilic dyes of the aminoalkyl type (Scheme 7.71). As in the case of the Basazol system on cellulose (Scheme 7.60), the intended formation of covalent dye-fibre linkages has to compete with side reactions, such as partial hydrolysis (Scheme 7.70), di- or trimerisation that may lead to less than optimum fastness, or substrate crosslinking that may adversely influence desirable fibre characteristics. 

The refining process involves the circulation of the fibre suspension in such a way as to force the fibres between a stationary metal plate (the stator) and a moving metal plate (the rotor). As the fibres are wet at this stage, both mechanical and hydraulic forces are involved in altering fibre characteristics. Both shear and normal stresses (either tensional or compressive) are imposed on the fibres in this process, and the mechanical action is shown diagramatically in Figure 5.1. 

Cellulose is reputedly the most abundant organic material on Earth, being the main constituent in plant cell walls. It is composed of glucopyranose units linked pi 4 in a linear chain. Alternate residues are rotated in the structure, allowing hydrogen bonding between adjacent molecules, and construction of the strong fibres characteristic of cellulose, as for example in cotton. 

Van der Linden and Sagis (2001) have suggested that, once a critical concentration for gel formation is known, one can predict, for example, the dependence of the gel elasticity on the concentration of protein. The minimum gelation concentration may be expressed in terms of the basic fibre characteristics like the stiffness and also as a function of salt concentration (Veerman, 2004 Sagis et al., 2004). It is pointed out by van der Linden (2006) that there are two important factors which allow the manipulation of this minimum gelation concentration to an extremely low value. The first factor is that the nano-fibre should be robust against dilution. And the second is that the fibre should robust also with respect to other treatments, especially the adjustment of the pH. It would appear that each of these conditions is satisfied. 

Janaway, R. C. (1983). Textile fibre characteristics preserved by metal corrosion The potential of SEM studies. Conservator 7, 48-52. 

The fibre characteristics depend on the source. Table 5.2 gathers the main characteristics of industrial vegetable fibres. A short description of every type of fibre and their applications are given in the following paragraphs. 

Yegles M, Janson X, Dong HY, et al. 1995. Role of fibre characteristics on cytotoxicity and induction of anaphase/telophase aberrations in rat pleural mesothelial cells in vitro Correlations with in vivo animal findings. Carcinogenesis 16 2751-2758. 

For over 40 years there have been intense efforts to develop improved eucalypt hybrids for 7 yr-old pulpwood crops. Elite clones of E. urophylla x grandis have both desired long fibre characteristics, i.e. long for a hardwood, and less variation despite consisting solely of variable corewood ... 

It is also interesting in damage analysis to know which fibre characteristics are determined in criminal investigations. Typical characteristics are ... 

Verdonck F, Carmeliet E. 1971. Isometric contractions in cardiac purkyne fibres Characteristics in Na free Srtyrode. Cardiovasc Res (Suppl. l) 76-83. 

Several yam manufacturing methods exist in the textile industry. The characteristics of the yam that is used in constmcting a fabric highly influences the mechanical properties of the fabric and similarly, the yam characteristics are strongly dependent upon the fibre characteristics and the yam stmcture. The yam can be formed by using either staple fibres or continuous filaments. Several spinning systems exist for processing staple fibre yams, each of which has a different structure and exhibits different properties. Similarly, continuous filament yams can be manufactured as either monofilaments or multifilaments, with or without twist imparted into them. 

Size—Any treatment which is applied to yarn or fibres at the time of formation to protect the surface and aid the process of handling and fabrication, or to control the fibre characteristics. The treatment contains ingredients which provide surface lubricity and binding action but, unlike a finish, contain no coupling agent. Before final fabrication into a composite, the size is usually removed and a finish applied. 

The simplest composite fibres are the B and SiC monofilaments manufactured by chemical vapour deposition of boron halide or silane gases onto a heated substrate, normally W or C. Their diameter is in the range of 50-150 p.m, and they exhibit a concentric microstructure in which four different regions can be distinguished, the composition and thickness of each one depending on the actual fibre characteristics (Fig. 9). A thin (1-2 i.m) layer of pyrolytic graphite is deposited onto the C core before the deposition of... 

Eisele D. (1996), Reclaimed fibres. Characteristics. Background, Melliand Textilberichte, 77, 4, 199-202. 

The role of fibres depends on their volume, aspect ratio, strength and bond to the matrix. It has been shown in many tests how these fibre characteristics influence the composite s behaviour. In recent years, particular attention has been paid to the distribution of fibres - very small and well dispersed fibres may control the microcracks in the matrix form the very beginning of their opening and particularly high deformability of the composite may be obtained (cf. Section 14.5). 

The approach is explained with the help of a case study Organic fibre prototype analysis out of the chemical process industry with the focus on the analysis of reliability parameters of fibre samples. With the use of nonparametric as well as parametric statistical methods, fibre characteristics (e.g. centre, dispersion, trends) and interdependences are analysed with regard to material, geometry and origin aspects. 

The application of internal standards or the use of the standard addition method for quantitation is strongly recommended for achieving low relative standard deviations (Nielsson etal., 1994 Poerschmann etal., 1997). After the equilibrium is established, the fibre with the collected analytes is withdrawn from the sample and transferred into a GC injector, either manually or more convenient via an autosampler. The analyte is desorbed thermally in the hot injector from the coating. The fibre material is used for a large number of samples in automated serial analysis. Modern autosampler are capable to exchange the fibre holder to provide automated access to different fibre characteristics according to the analyte requirements. 

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