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textile fibers

By Anita Perkins,2014-10-19 14:49
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textile fibers

Textile Fibers

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1( 班级学号第一)

    An Introduction to Textile Fibers and Fiber classification

    In the early stages of scientific development it became obvious that placing like items together made for increased understanding; thus, systems of classification were established and have been in use for hundred of years. When the study of textile fibers was new, a simple type of classification was sufficient--one based on a systematic arrangement of fibers into the categories of animal, vegetable, and mineral matter.

     With the development of man-made fibers this classification system became obsolete, and new systems had to be devised. It was apparent to those studying textiles that soon it would be practically impossible to remember all the properties and characteristics of each individual fiber. Thus, scientists reasoned that if fibers could be classified into like groups, a person could become acquainted with the general properties of each group and would then need to know only the special properties of individual fibers in order to select, use, and care for textile products intelligently.

    Over the years, many systems of classification have been recommended. Some are no longer sufficiently discerning for the innumerable fibers on the market at the present time. Several older systems are still helpful for major divisions, but owing to the complexity of the current fiber situation, it is now necessary to add selected sub-classifications.

     The Textile Fiber Products Identification Act (TFPIA) was enacted in 1959 and became law in 1960. This legislation requires most textile products sold at retail to have labels securely attached that identify the fiber content. To help reduce consumer confusion, this legislation, through several amendments, now provides for twenty-one generic, or family, names into which all manufactured fibers of anticipated commercial value may be grouped. The law identifies directions for label format as well as the generic names. Manufacturer trademark names may be used with any fiber generic name. The trademark name is capitalized whereas the generic name is not.

    Table 1-1 presents a classification system for natural fibers. The general headings of cellulosic, protein, mineral, and natural rubber have been used rather than the basic division of matter--animal, vegetable, and mineral. These latter divisions have been challenged because there are differences between the behavior of vegetable cellulose and vegetable protein, both of which may be used in fiber manufacture.

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2 ( 班级学号第二)

    TABLE 1-1 Natural fibers

A. cellulosic fibers a. wool

    1. seed fibers b. specialty hair

    a. cotton (1) alpaca

    b. kapok (2) camel

    2. bast fibers (3) cashmere

    a. flax (4) mohair

    b. ramie (5) vicuña

    c. hemp c. fur fibers

    d. jute (1) Angora rabbit

    3. leaf fibers 2. animal secretion

    a. abaca a. silk

    b. pineapple (1) cultivated silk

    c. agave (sisal) (2) wild silk

    4. nut husk fibers b. spider silk

    a. coir (coconut) C. mineral fiber

    B. protein fibers 1. asbestos

    1. animal-hair fibers D. natural rubber

     Table 1-2 presents a workable classification system for all manufactured or man-made fibers. This table is based, primarily, on the generic terms identified by the TFPIA. Each generic term has been asterisked for easy identification. For commonly encountered generic groups, a few trademark names have been cited. The generic terms are not capitalized, but all trademark names are.

    In using the classification charts, one should remember that specificity needs may vary with different groups of consumers. The list of fibers under each category is not complete. For example, there are many more bast fibers than those listed in Table 1-1.1. Specific fibers included are those that are considered commercially important, easily recognizable, and useful to consumers. Students wishing to study some of the less familiar fiber in detail will find additional data in references listed in the bibliography.

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3 ( 依班级学号排列)

    TABLE 1-2 Man-made or manufactured fibers

    A. Man-made cellulosic fiber: e. type 6,10 Solvron

     1. rayon * Nylex 11. vinyon *

     a. cuprammonium rayon Quill Avtex

     b. viscose rayon f. nylon, aromatic types Rhovyl

     (1) regular- and high- Qiana 12. novoloid *

     tenacity rayon g. nylon, bicomponent types Kynol

     Avtex 2. aramid * 13. spandex *

     Fibro Kevlar Lycra

     Coloray, solution-dyed Nomex Glospan

     Durvil 3. polyester * Cleerspan

     Enkrome, solution-dyed A.C.E. 14. rubber *

     (2) high-wet-modulus Avlin 15. lastrile * * (There are no las-

     rayon Blue C, Monsanto trile fibers currently in

     Avril Dacron production.)

     Zantrel Encron E. Man-made mineral fibers B. Man-made modified cellulosic Fortrel 1. glass *

     Fibers Golden Touch Beta

     1. acetate * Kodel Fiberglas

     a. secondary acetate Ultra Touch PPG

     Avron Trevira 2. metallic *

     Celanese acetate 4. anidex * (none currently pro- Brunsmet

     Chromspun, solution-dyed duced in the United States) Chromel R

     Lanese 5. acrylic * Lurex

     Loftura Acrilan X-static

     Estron Creslan F. other man-made fibers

     b. triacetate * * Fina 1. miscellaneous types of

     Arnel Orlon polyester fibers

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    C. Man-made protein fibers Zefran Lexan, a polycarbonate

     1. azlon * (none currently pro- 6. modacrylic * A-Tell, a polyethylene

     duced in the United States) SEF oxybenzoate D. Man-made noncellulosic fibers Verel PBI, a polybenzimidazole

     1. nylon * Kanekalon 2. alginate

     a. type 6,6 7. nytril * (none currently pro- 3. inorganic fibers

     Antron duced in the United States) Avceram, carbon silica

     Astroturf 8. olefin * Thornel, graphite

     Blue C, Monsanto a. polyethylene Boron

     Cadon Tyvek Sapphire whiskers

     Cumuloft b. polypropylene 4. biconstituent and bicompo-

     DuPont Herculon nent fibers

     b. type 6 Marvess Raycelon, rayon and nylon

     Caprolan Polyloom Source, nylon, polyester

     Anso Typar Tricelon, nylon and acetate

    Enkalure Vectra Monvelle, nylon, spandex

    Enka 9. saran * 5. tetrafluoroethylene

    Zeftron Bolta Teflon

    Shareen Harlan Halar

    Golden Touch Saran 6. polychal

     c. type 6T 10. vinal * Cordelan

     d. type 11 Kuralon 7. promix

    Rilsan Mewlon Chinon

* Generic terms as identified in the TFPIA

    ** Terms that may be used as generic names when the fiber meets special requirements as cited in the TFPIA

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    It should be noted that the TFPIA legislation used in the fiber classification of this text does not provide new names for natural fibers. Except for hair fiber, nature fibers are identified by their common name in labeling textile products. Legislation, as cited in the Wool Products Labeling Act, provides that all hair fibers may be labeled as "wool." However, the name of the actual animal, such as vicuña, has sufficient selling power so that products of this type usually are labeled by animal name or by a special name given to the fiber, such as mohair.

     Trade names for fibers cited in Table 1-1.2 are limited to those that are frequently seen on labels. For most of the man-made fibers, there are additional trademarks used by fiber manufacturers, and in some instances no trademark or trade name is used, only the generic fiber name. For readers wishing a more complete list of trademarked fibers please see such resources as those by Dembeck, Man-made Fiber Producers Association, and Textile World.

     The original Textile Fiber Products Identification Act provides for adding new generic classes when necessary. Four that have been added since enactment of the legislation include: lastrile, anidex, aramid, and novoloid.

     The TFPIA requires only that the generic name of the fiber or fibers be listed on an attached label. However, some manufacturers find that listing a trademark name attracts consumers who have become familiar with that name and who respect its quality. Some consumers may find trademark names more helpful than others. Regardless of knowledge of trademark names, the consumer who can recognize fiber generic names and evaluate such fibers, based on sound knowledge of properties and characteristics, will be apt to be satisfied as a result of the decision-making process involved in the textile selection. Informed consumers have the advantage of understanding why fibers react as they do to physical, chemical, and biological stimuli. This in turn provides the foundation for intelligent selection, use, and care of textile products.

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    Natural Cellulosic Fibers / 天然纤维素纤维

    2.1 Introduction of natural cellulsosic fiber

    Fibrous materials are found in nearly all plant life, but some plants in particular have proved to be important sources of textile fibers for the manufacture of yarns, cord, and fabrics. These plant fibers consist largely of cellulose and, therefore, are classified as natural cellulosic fibers.

    This term indicates the simple chemistry of the substances and provides a scientific method for comparing natural cellulose with man-made cellulose fibers. The natural cellulose fibers commonly encountered in consumer goods include cotton, flax (linen fabric), jute, and hemp. Other natural cellulose fibers may be found in textile products imported from other countries. The following discussion summarizes the general characteristics of natural cellulosic fibers and rayon as a class or group. Cellulose acetate and cellulose triacetate are chemical variants of cellulose and, as such, do not share in many of the ―family characteristics.‖

     The density of cellulosic fibers tends to be relatively high, making fabrics woven from yarns of these fibers feel comparatively heavy. Cellulosic fibers have relatively low elasticity and resilience. As a result, they wrinkle easily and do not recover from wrinkling readily. Absorbency and moisture regain are generally good. Most cellulosic fibers are, therefore, slow to dry after wetting, comfortable to wear, and easy to dye.

     Cellulosic fibers are good conductors of heat and electricity. As good conductors of heat, they carry warmth away from the body, and are favored for use in hot weather and warm climates. Since they conduct electricity, cellulosic fibers do not build up static electricity, which produces shocks when garments are worn.

     Cellulosic fibers tend to burn easily, with a quick, yellow flame, much as paper (which is also cellulose). Most cellulosic fibers can, however, withstand fairly high dry heat or ironing temperatures before they scorch. On an electric iron, cotton and linen setting are the highest settings on the dial.

     Chemical properties of cellulosic fibers include good resistance to alkalis. Excessive bleaching will harm cellulosic fibers, although carefully controlled bleaching is less detrimental. Strong mineral acids are quite damaging, and most natural cellulosic fibers will withstand high water temperatures. Such properties permit laundering of cellulosic fibers with strong detergents, controlled bleaching, and hot water temperatures. Regenerated cellulosic fibers are more sensitive to chemicals and require more careful handling and gentle agitation with lower water temperature.

     Most insects do not attack cellulosic fibers. However, silverfish are likely to attack heavily starched cellulosic fabrics. Most cellulosic fabrics are susceptible to attack by fungi, especially mildew. Extended exposure to sunlight tends to damage the fibers

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    2.2 Cotton

    2.2.1 Textile classification

    The word cotton is derive from the Arabic. Depending upon the Arabian dialect, it is pronounced kutan, qutn, qutun, etc. As the cotton fiber is obtained from a plant it is classified as a natural, cellulose, seed, mono-cellular, staple fiber. The density of the fiber (referred to from

    3now on as fiber density ) is 1.52g/cm,which makes cotton a rather heavy fiber.

    2.2.2 Physical properties

    Tenacity

    The strength of cotton fibers is attributed to the good alignment of its long polymers (that is , its polymers system is about 70 per cent crystalline ), the countless, regular, hydrogen bond formations between adjacent polymers, and the spiraling fibrils in the primary and secondary cell walls.

     It is one of the few fibers which gains strength when wet. it is thought this occurs because of a temporary improvement in polymer alignment in the amorphous regions of the polymer system . The improved alignment when wet results in an increase in the number of hydrogen bonds , with an approximate 5 per cent increase in fiber tenacity.

    Elastic-plastic nature

    The cotton fiber is relatively inelastic because of its crystalline polymer system , and for this reason cotton textiles wrinkle and crease readily. Only under considerable strain will cotton polymers give and slide past one another. They are usually prevented from doing so by their extreme length and countless hydrogen bonds, which tend to hold them within their polymer system. Bending or crushing of cotton textile materials places considerable strain on the fibers

    polymer systems. It will probably cause polymer fracture since the crystallinity of the polymer system makes it difficult for cotton polymer to be displaced by bending or crushing forces. Polymer fracture results in polymer disarrangements. These become weak points in the polymer system, and hence weak areas in the cotton fiber structure. Such weakening of the polymer system, and therefore fiber structure, cause cotton textile materials to crease and wrinkle readily.

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    Hygroscopic nature

    The cotton fiber is very absorbent, owing to the countless polar OH groups in its polymers;

    these attract water molecules, which are also polar. However, the latter can only enter the polymer system in its amorphous regions, as the inter-polymer spaces in the crystalline regions are too small for the water molecules. Aqueous swelling of the cotton fiber is due to a separation or forcing apart of polymers by the water molecules in the amorphous regions only. The general crispness of dry cotton textile materials may be attributed to the rapidity with which the fibers can absorb moisture from the skin of the fingers. This rapid absorption imparts a sensation of dryness which, in association with the fibers inelasticity or stiffness, creates the

    sensation of crispness.

    The hygroscopic nature ordinarily prevents cotton textile materials from developing static electricity. The polarity of the water molecules, attracted to the hydroxyl groups on the polymers, dissipates any static charge which might develop .

    Thermal properties

    Cotton fibers have the ability to conduct heat energy, minimizing any destructive heat accumulation. Thus they can withstand hot ironing temperatures. There is no satisfactory explanation for this.

    Excessive application of heat energy causes the cotton fiber to char and burn, without any prior melting. This is an indication that cotton is not thermoplastic, which may be attributable to the extremely long fiber polymers and the countless hydrogen bonds they from. These prevent the polymers from assuming new positions when heat is applied, as would be the cause with the shorter polymers of thermoplastic fibers. When sufficient heat, that is, kinetic energy, is applied to the cotton fiber, its polymers will begin to vibrate or become so excited as to disintegrate. This in conjunction with the large quantity of kinetic energy present results n violent chemical reactions observed as fiber combustion.

    2.2.3 Biological properties

    Cotton is damaged by various microorganisms. Mildew will produce a disagreeable odor and will result in rotting and loss of strength. Certain bacteria encountered in hot, moist, and dry conditions will cause decay. Moths and beetles that damage some fibers will not usually attack cotton; but silverfish do eat cotton cellulose, especially if it has been sized.

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    2.2.4 Cotton in use

    Cotton has been the most universally used single textile fiber. It is still the most used fiber world wide. It is excellent for a multitude of end uses. Fabrics of cotton and cotton blends are available in a wide price range. Inexpensive cotton fabrics are commonly found in standard fabric types such as muslins, percales, and broadcloth. Expensive cotton fabrics are available for use in high-fashion clothes, special home-furnishing fabrics, and other special end uses. The relative cost of cotton fabrics is influenced by such factors as finishing processes, chemicals used in processes, and equipment cost. High-cost construction operations, such as Jacquard weaving and the application of special surface designs developed by well-known artists, also increase the cost of the fabric.

     Cotton and cotton blends have almost total universal consumer acceptance. They provide fabrics with varying degrees of comfort, easy care, and good durability. Since 1980 there has been a move to promote blends with a high percentage of cotton. These blends with 65 to 80 percent cotton are considered to be attractive, easy to care for, and comfortable. They also tend to satisfy those consumers who are asking for natural fiber products.

     Cotton fibers create fabrics that are comfortable owing to the characteristics of softness, moisture absorbency, air permeability, and pliability. As a result of fiber strength, which increases when wet, cotton fabrics are relatively easy to launder; in addition, they may be dry cleaned when fabric style and construction require it. Cotton possesses desirable properties--including good water absorbency--which are responsible for comfort in use. The ability of cotton to be bleached and to launder well ensures the consumer of an attractive white product for its useful life; its acceptance of quality colorfast dyes ensures the retained color in colored products. However, consumers must adhere to recommended use and care procedures. Other characteristics that help produce fabrics that are desired by consumers include pliability and flexibility, heat resistance, easy dyability, and color application. Special finishing processes must be given cotton fiber in order to produce cotton fabrics that are water repellent, stain and spot resistant, flame retardant, shrinkproof, and/or durable press. Cotton fibers accept these finishes easily and retain them through normal use and care.

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