Textile fibers studies

An important aspect of the mechanical properties of fibers concerns their response to time dependent deformations. Fibers are frequently subjected to conditions of loading and unloading at various frequencies and strains, and it is important to know their response to these dynamic conditions. In this connection the fatigue properties of textile fibers are of particular importance, and have been studied extensively in cycHc tension (23). The results have been interpreted in terms of molecular processes. The mechanical and other properties of fibers have been reviewed extensively (20,24—27). 

Examination. Specific questions arising in the study of textiles include the identification of the textile fiber. Microscopy is the most important approach. 

In a study of the adsorption of soap and several synthetic surfactants on a variety of textile fibers, it was found that cotton and nylon adsorbed less surfactant than wool under comparable conditions (59). Among the various surfactants, the cationic types were adsorbed to the greatest extent, whereas nonionic types were adsorbed least. The adsorption of nonionic surfactants decreased with increasing length of the polyoxyethylene chain. When soaps were adsorbed, the fatty acid and the aLkaU behaved more or less independently just as they did when adsorbed on carbon. The adsorption of sodium oleate by cotton has been shown independently to result in the deposition of acid soap (a composition intermediate between the free fatty acid and the sodium salt), if no heavy-metal ions are present in the system (60). In hard water, the adsorbate has large proportions of lime soap. 

In Industry. For the study of irregularities in the dyeing and weaving of textile fibers, the interior of furnaces, the detection of carbon in lubricating oils, infrared spectroscopy of metals and alloys. 

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. 

X-Ray diffraction studies of textile fibers have led to the development of techniques to calculate or estimate the following fiber characteristics ... 

However, electron diffraction, although frequently used for polymer single crystals studies, has seldom been applied to textile fibers, and particularly to ultrathin sections of those materieIs. (1,2) the majority of published papers dealing with electron diffraction of fibers is concerned with isolated fibrils or fragments prepared by mechanical milling. 

The fact that covalent bonding can be an important, and possibly necessary, contribution to water-proof adhesive bonds to wood has convinced many scientists to study methods of enhancing adhesion by increasing the probability of covalent bonding between wood and adhesive, or directly between wood particles. This subject is still in its infancy with solid wood, although pulp and textile fiber scientists have produced an enormous volume of literature from which wood scientists can draw. 

In addition to wool, other hygroscopic textile materials such as cotton and linen underwent a threefold increase in their specific heat at constant vapor pressure. The relatively high specific heats derived from equations in the study, which are considered to represent those incurred in actual use of the hygroscopic textiles, explain the well-known buffering action of these fabrics toward sudden changes in indoor or outdoor temperatures (2l). A compilation of the specific heat of a variety of textile fibers at 20-200°C indicates that considerable variation in the values of this thermophysical property occurs with different fibers (e.g., a value of 0.157 for glass and 0.1 9 cal/g.°C for Nylon 66 are reported), and that additional research is needed to establish the extent to which specific heat affects the characteristics of thermal transmission in textiles (22). 

Researchers have examined the creep and creep recovery of textile fibers extensively (13-21). For example, Hunt and Darlington (16, 17) studied the effects of temperature, humidity, and previous thermal history on the creep properties of Nylon 6,6. They were able to explain the shift in creep curves with changes in temperature and humidity. Lead-erman (19) studied the time dependence of creep at different temperatures and humidities. Shifts in creep curves due to changes in temperature and humidity were explained with simple equations and convenient shift factors. Morton and Hearle (21) also examined the dependence of fiber creep on temperature and humidity. Meredith (20) studied many mechanical properties, including creep of several generic fiber types. Phenomenological theory of linear viscoelasticity of semicrystalline polymers has been tested with creep measurements performed on textile fibers (18). From these works one can readily appreciate that creep behavior is affected by many factors on both practical and theoretical levels. 

The degree of sensitivity that the textile fibers showed (both to the accelerated aging and to the different washing treatments) demonstrated that cellulose from cotton and linen textiles can be expected to be as susceptible to degradative processes as are the more extensively studied rag fiber papers. Therefore, much of the literature concerning treatments carried out on paper substrates should be applicable to textile conservation. However, it is still important to exercise caution in applying results from wood pulp papers to textile artifacts. 

Modification of Textile Fibers. The reaction of hydrophobic chemicals with textile fibers offers the possibUity of permanent repeUency without alteration of the other physical properties of fibers. However, the disadvantages caused by complex processing, and resultant higher costs of carrying out chemical reactions on fiber in commercial textile plant operations, have limited the commercial appHcations. The etherification and esterification of ceUulose have been most effective in terms of achieving durable water repeUency (32,33). Radiation grafting of reactive repeUents onto fibers has been studied as a potential commercial process (34,35), as has modification by plasma polymerization of gas monomers or plasma initiated polymerization of Hquid monomers (36). 

Comparing and Contrasting Match each of the following research topics with the branch of chemistry that would study it water pollution, the digestion of food in the human body, the composition of a new textile fiber, metals to make new coins, a treatment for AIDS. 

IGC has been used at zero surface coverage to characterize the surfaces of cellulose (5), cellophane (6), and poly(ethylene terephthalate) film (7 ). Surface properties of Intact textile fibers were also studied by IGC (8). Domlngo-Garcla et al. (9 ) have recently characterized graphite and graphltlzed carbon black surfaces with this method, and some zero coverage results on carbon fibers have appeared (10). 

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