TAM Quiz 1

Fabric

A flexible planar substance constructed from solutions, fibers, yarns, or fabrics, in any combination. (See Figure 1.1.) Fabrics range from lightweight and sheer chiffon scarves to heavy and sturdy denim to rigid and firm carpeting to technical products such as erosion control and medical tapes. (See Figures 1.2, 1.3, and 1.4.) Cloth and material are common synonyms for fabric.

Textile

A term originally applied only to woven fabrics, now generally applied to any flexible material that is composed of thin films of polymers or of fibers, yarns, or fabrics or products made of films, fibers, yarns, or fabrics.

Yarn

An assemblage of fibers that is twisted or laid together so as to form a continuous strand that can be made into a textile fabric. Yarns can be used to make a fabric that is smooth and slick like satin or soft and fuzzy like brushed denim.

Cost of Wool

High cost in comparison to substitutive fibers, and considered an investment. However wool's combined properties: the ability to be shaped by heat and moisture, good moisture absorption without feeling wet, excellent heat retention, water repellency, feltability, and flame-retardancy are not equaled by any manufactured fiber.

Technical or industrial textiles

Include a broad range of materials that are widely used in special applications of a technical nature and that are generally not considered apparel or furnishings.

Translucence (Aesthetic Property)

the ability of a textile to allow light to pass through it. Fibers that are transparent or translucent like nylon or polyester must be altered during production with additives or by changing their cross section to provide cover.

Cohesiveness (Durability Property)

the ability of fibers to cling together during spinning, can be a factor in durability. Fibers with good cohesiveness tend to resist raveling or slipping during use. Cotton and wool have good cohesiveness while silk and polyester have poor cohesiveness.

Feltability

the ability of fibers to mat together

Flexibility (Durability Property)

the ability to bend repeatedly without breaking, is an important property related to abrasion resistance. Some fibers like silk and wool have superior flexibility, while others like glass break very quickly after very few bends and are not used for apparel or other consumer products because the broken bits of fiber are irritating to the skin.

Strength (Durability Property)

the ability to resist stress

Fabric Crimp

the bends caused by distortion of yarns due to weaving and knitting a fabric

Keratin

the cross-linked fiber wool is made from same protein that is found in horns, hooves, and in human hair and fingernails. consists of carbon, hydrogen, oxygen, nitrogen, and sulfur. combine to form over 17 different amino acids. The flexible molecular chains of wool are held together by natural cross links—cystine (or sulfur) linkages and salt bridges—that connect adjacent molecules.

Thick-and-thin fiber types

vary in their diameter along their length as a result of uneven drawing or stretching after spinning. This produces a fiber thinner in some areas and thicker in other areas producing fabrics with a texture like dupioni silk or linen. The thick nubby areas dye a deeper color to create interesting tone-on-tone color effects. Many surface textures are possible by changing the size and length of the slubs.

Long Staple Cottons (3 Types)

Long-staple cottons, which are 16/16 to 1½ inches in length, were developed from Egyptian and South American cottons. Varieties include American Pima, Supima, Egyptian, American Egyptian, and Sea Island cottons. Cotton from the Gossypium barbadense variety is about 3% of the crop and is mainly produced in California. Higher Quality ex. Pima, Supima, Egyptian, or Sea Island (Figure 4.7). Or they may be referred to as long-staple or extra-long-staple (ELS) cotton.

Five means of modification

Modify the size and shape of the spinneret to produce fibers of different sizes and shapes. Modify the fiber's molecular structure and crystallinity to enhance fiber durability. Add other compounds (additives) to the polymer or dope to enhance fiber performance. Modify the spinning process to alter fiber characteristics. Combine two polymers as separate entities within a single fiber or yarn.

Merino Sheep

Produce the most valuable wool because their fleece is dense and fine with regular crimp patterns. Australia produces about 50% of the Merino wool. Good-quality fleeces weigh 15 to 20 pounds each. Merino wool is 3 to 5 inches long. It is used to produce high-quality, long-wearing products with a soft hand and luster and good drape.

Soft Goods

Products constructed of textiles and other flexible materials including apparel, interior textiles, and technical textiles.

Cottonizing

Reduces a bast fiber to a length similar to that of cotton. These cottonized fibers can be processed on equipment designed for cotton but may lack some of their more traditional characteristics related to hand, luster, and durability. Flax, ramie, and hemp are bast fibers that are frequently cottonized.

Upland Cottons (3 Types)

Upland cottons (Gossypium hirsutum, the predominant type of cotton produced in the United States) are 7/8 to 1¼ inches in length and were developed from cottons native to Mexico and Central America. Approximately 97% of the U.S. crop is an Upland variety.

Fine Fibers (diameter)

Used to make apparel and interior finishings, natural fine fibers are of better quality and are measured in micrometers

Large Fibers (diameter)

Used to make durable products (not as comfortable) like bookbags.

Standard Test Methods

Used to test factors and performance of a fabric

Amorphous

When the chains are arranged in a random or disorganized way within the fiber Amorphous fibers such as wool, cotton, and rayon are relatively weak and easily elongated. These fibers also have poor elasticity and good moisture absorbency, dyeability, and flexibility.

Crystalline

When the molecular chains are organized parallel to each other

Aesthetics

addresses the appearance or attractiveness of a textile product. Does the item look pleasing and appropriate for its end use? Does it make the right statement for the target market? Aesthetics includes the specific textile components of texture, luster, pattern or motif, color, opacity, drape, stiffness, and surface characteristics.

Comfort

addresses the way textiles affect heat, air, and moisture transfer, and the way the body interacts with a textile product.

Conventional Cotton

all other cottons

Composition of Protein Fibers

amino acids forming polypeptide chains, containing Oxygen, Nitrogen, Hydrogen and Carbon. Amphoteric: contain both acidic and basic reactives

3 Parts of a Natural Fiber:

an outer covering called a cuticle or skin; an inner area; and a central core that may be hollow

Filament tow

an untwisted rope of thousands of filament fibers. The rope combines the fibers from many spinnerets, each of which has thousands of holes. The tow is crimped and converted into staple by cutting or breaking to the desired length. (See Chapter 10 for methods of breaking filament tow into staple fibers.)

manufactured fiber

any fiber derived by a process of manufacture from chemical compounds where the original form is not recognizable as a fiber. There are many different manufactured fibers available today. The differences among the fibers are due to the chemistry of the polymer

Where does cotton grow

any place where the growing season is long (cotton needs 160 to 180 days to mature) and the climate is temperate to hot with adequate rainfall or irrigation. Cellulose will not form if the temperature is below 70°F.

Fiber modifications

are changes in the parent manufactured fiber to improve performance relative to a specific end use. Modifications of the parent fiber may be sold under a brand or trade name. Modifications may also be referred to as types, variants, or x-generation fibers, where the x could be any number such as second, fifth, or tenth generation.

Cashgora

by breeding feral cashmere goats with angora goats

Stretching or drawing

causes the chains to slide and become more parallel to each other and to the longitudinal axis of the fiber. It also reduces fiber diameter and compacts the molecules. Fiber properties affected by crystallinity and orientation include strength, elongation, moisture absorption, abrasion resistance, and dyeability.

Character of Cotton

cludes such fiber aspects as maturity, smoothness, and uniformity of fibers within the bale, fiber fineness, strength, and convolutions. Micronaire values, which reflect both fineness and maturity, are assessed by forcing air through a standard weight plug of cotton fibers compressed to a fixed volume. Lower micronaire results indicate less mature and coarser fibers, while higher values indicate more mature and finer fibers. Character identifies the amount of processing necessary to produce a good white fabric for commercial use. Because of yearly variations in growing conditions and in geographic locations, yarn and fabric producers carefully select and blend cottons so that the cotton fabrics and products are as uniform from year to year as possible.

Lamb's Wool

comes from animals less than 7 months old, fine and soft, usually identified on a label, has one cut end and the other is a natural tip

Globalization

companies purchasing from and/or selling to multiple sites in the world and applies to many industries, including the textile complex. Globalization requires use of advanced technologies to satisfy a wide variety of consumers and to coordinate the purchasing, manufacturing, and distribution to multiple locations worldwide.

trade names

companies' names for fibers and may be used in promotion and marketing. Certification requirements for use of a trade name or trademark allow the owner to set minimum performance standards for a product that carries the trade name or trademark. Trade names for generic fibers, like Tencel lyocell, are used less often, while trade names for special fiber modifications, like Supplex nylon, are used widely to promote products.

Safety

considers a textile's ability to protect the body from harm. Is this item comfortable for its end use in terms of absorbency, temperature regulation, and hand? Will its comfort change with use, care, or age? How does it feel? Is it safe to use or wear?

Appearance Retention

considers how the product maintains its original appearance during use and care. Will the item retain its new look with use and cleaning? Will it resist wrinkling, shrinkage, abrasion, soiling, stretching, pilling, sagging, or other changes with use? Will it age quickly or slowly?

Green Cotton

describes cotton fabric that has been washed with mild natural-based soap but has not been bleached or treated with other chemicals, except possibly natural dyes.

Sustainability

describes practices and policies that reduce environmental pollution and do not exploit people or natural resources in meeting the lifestyle needs of the present without compromising the future. Sustainability deals with the life cycle impact of products.

Performance

describes the manner in which a textile, textile component, or textile product responds to use or how it responds when exposed to some mechanical or environmental factor that might adversely affect it. Textile product performance cannot be determined solely on a single component such as fiber content or fabric structure

Durability

describes the manner in which the product withstands use, that is, the length of time the product is considered suitable for the use for which it was purchased. Will the consumer be satisfied with how well it wears, how strong it is, and how long it remains attractive? Is the product strong, tear and abrasion resistant, snag-proof, and pill resistant?

Serviceability

describes the measure of a textile product's ability to meet consumers' needs. The emphasis of serviceability is on understanding the target market and relating target market needs to product serviceability. The serviceability concepts that are used to organize the information are aesthetics, durability, comfort, safety, appearance retention, care, environmental concerns, sustainability, and cost

Grading Wool

evaluating the whole fleece for fineness and length in order to group wool of the same quality

Cradle-to-cradle concept (Environmental)

examines the overall impact of the production, use, care, disposal, and recycle potential of products, from economic, industrial, and social perspectives.

seed fiber (ex. cotton)

grows within a pod or boll from developing seeds.

Product Quality

has become an important dimension in the competitive global marketplace. But the term is difficult to define because it means different things to consumers and producers.

Crimp in Wool

helps the elasticity and strength, makes wool ideal for sweaters

Fiber Identification Methods

microscope, solubility, and burn tests

Raw/Grease Wool

newly removed wool which contains between 30% and 70% by weight of such impurities as sand, dirt, grease, and dried sweat (suint)

Clean/Scoured Wool

once the impurities of raw wool are removed, clean wool is left.

Physical Structure

or morphology, can be identified by observing the fiber using a microscope. In this book, photomicrographs, in which fibers are magnified 250 to 1,000 times, show details of a fiber's physical structure. In addition, fiber measurements influence fabric characteristics and performance and the process that will be used in producing a finished fabric.

Filament Tow

produced as a loose rope of several thousand fibers, is crimped or textured, and cut to staple length.

Mohair

specialty wool of the angora goat, shed twice a year, most of the hair is adult hair coarse and with no crimp, more resilient and stronger, better with dyes, less expensive than other specialty wools

Apparel

Clothing and accessories made from flexible materials.

Polymer

A very large molecule made by connecting many small molecules together. Almost all fibers are polymers made of organic materials, but some polymers are formed into thin films and used as textiles. For example, vinyl upholstery is a film, often applied to a more traditional textile knit or woven material for added durability.

linters

After ginning, the seeds are covered with very short fibers—1/8 inch in length—called linters. The linters are removed from the seeds and are used to a limited extent as raw material in producing rayon and acetate. Linters are used to stuff small decorator pillows and are used in automotive upholstery, mops, candlewicks, blankets, mattresses, twine, rugs, and medical supplies. Linters are also converted into cellophane, photographic film, fingernail polish, and methylcellulose used in makeup and chewing gum. The seeds are crushed and refined to obtain cottonseed oil used in human foods such as salad dressings and meal for use in livestock feed, pharmaceuticals, and soap stock. The hulls are used in animal feed, fertilizer, garden mulch, and oil drilling mud to plug leaks in oil wells.

Common to all cellulosic fibers

All cellulose fibers contain carbon (C), hydrogen (H), and oxygen (O). The basic monomer of cellulose is glucose. The chemical structure to the left shows two glucose units (the second one is inverted) that repeat thousands of times to form cellulose. This two-glucose repeating unit is called cellobiose. The chemical reactivity of cellulose is related to the hydroxyl groups (-OH) of the glucose unit. The hydroxyl group reacts readily with moisture, dyes, and many finishes, making it a very versatile fiber. Chemicals such as chlorine bleach damage cellulose by attacking the oxygen atom between the two ring units or within the ring, rupturing the chain or ring.

Interior textiles

Also known as interior furnishings or home fashions; describe textiles and textile products used in the home and other building interiors for functions such as absorbency or to add comfort and visual interest. Home fashions (upholstered furniture, carpets and rugs, wall coverings, draperies and curtains, table linens, and towels and bed linens)

Coloration

Any dyeing or printing process used to add color with dyes or pigments to a textile. Coloration adds interest and fashion appeal to apparel and interiors.

Gray goods (grey or greige goods)

Any fabric that has not been finished. Consumers rarely see gray goods, except for home sewers and quilters who may work with muslin.

Finish

Any process that modifies appearance or enhances performance of gray goods (unfinished fabric). Some finishes make the fabric more comfortable such as brushing velveteen to produce the soft surface. With other finishes, the consumer cannot determine the presence of a finish. For example, a pair of cotton slacks may have a stain-resistant finish that makes stains easier to remove, but the consumer will not be able to see the finish and will only know of its presence if such information is included on labels or tags.

Fiber

Any substance, natural or manufactured, with a high length-to-width ratio possessing suitable characteristics for being processed into fabric; the smallest component, hairlike in nature that can be separated from a fabric. Fibers can be absorbent (like cotton and rayon), stretchy (like spandex), warm and bulky (like wool), or very strong and abrasion resistant (like nylon and polyester)

Spinneret modifications

Because fiber size often dictates end use, it is not surprising that changing the fiber size is a common modification. The simplest way to do this is to change the size of the opening in the spinneret. Other ways of changing fiber size include controlling the stretching or drawing after fiber extrusion or controlling the extrusion rate through the spinneret. Finer fibers, those with a denier of less than 7, are most often used for apparel. Deniers ranging from 5 to 25 are used in interior textiles. Technical applications have the widest range of denier, ranging from less than 1 for polishing lenses for glass and optical applications to several thousand for ropes and fishing line. Because fibers with extremely tiny sizes are made, macrofiber describes fibers with a denier greater than 1.0. Microfibers are fibers with deniers of less than 1.0; most range from 0.5 to 0.8 denier per filament (dpf). Ultrafine fibers are less than 0.3 dpf. Larger-sized fibers are used where greater strength, abrasion resistance, and resiliency are required. For example, carpet fibers with deniers in the range of 15 to 24 are more resilient. Higher-denier fibers resist crushing better than lower-denier fibers. Microfibers and ultrafine fibers are produced by modifying the spinning technique or by splitting or separating the filaments. Polyester ultrafine fibers with modified cross sections with slight fiber irregularities are sometimes referred to as shin-gosen, a Japanese term that means new synthetic fiber. Technical innovations in fiber production and processing result in products with exceptional consumer performance characteristics. In apparel and interiors, these fibers mimic the appearance and hand of silk. A yarn of microdenier fibers or microfibers may have as many as four times more fibers than a regular fiber yarn of the same size. Microdenier generic fibers include polyester, nylon, acrylic, and rayon in apparel and interiors in staple and filament form. Fabrics made from these fibers are softer and are more drapeable, silklike, comfortable, and water-repellent. Figure 6.3 compares regular and microfiber fabrics. Microfibers may be present by themselves in fabrics or in blends with no more than 60% natural or other manufactured fibers in order to retain the microfiber's characteristics. End uses include coats, blouses, suits, sleepwear, active sportswear, hosiery, upholstery, window treatments, bedding, and wall coverings. Microfibers required modifications in yarn-spinning frames, looms and sewing machines, and dyeing and finishing techniques. Mixed-denier filament bundling combines fibers of several denier sizes in one yarn (Figure 6.4). Microfibers (0.5 dpf) contribute the buttery hand to the fabric, while the macrofibers or regular denier fibers (2.0 dpf) contribute drape, bounce, and durability. When the fabric is laundered, the macrofibers shrink slightly, forcing the microfibers to the fabric's surface and enhancing the hand. Even smaller than microfibers, nanofibers are fibers with cross sections measuring less than 1,000 nm. (One nanometer is 1 3 10-9 meters.) A human hair is 80,000 nm. Nanofibers are much, much smaller than regular or macrofibers used in most apparel and interior textiles. (See Figure 6.5.) Nanotubes are hollow nanofibers. Nanofibers are made by several techniques including those discussed with micro- and ultrafine fibers. Another technique, electrospinning, forces the fiber through a tiny spinneret opening into an electric field. Nanofibers and nanotubes have high surface-to-volume ratios, small pore size, flexible surface functions, biocompatibility, and enhanced mechanical and electrical properties. Nanofibers and nanotubes are used in protective apparel, safety harnesses, and filtration for technical and medical applications. Smart textiles use nanofibers, nanotubes, and nanotechnology to produce materials that react to the environment. Micro-, ultrafine, and nanofibers are also used in technical applications where extremely fine fibers are needed. (For additional nanotechnology applications in the textile complex, see Chapters 9, 15, and 18.)

Chemicals of cotton

Cotton, when picked, is about 94% cellulose; in finished fabrics it is 99% cellulose. Like all cellulose fibers, cotton contains reactive hydroxyl groups. Cotton may have as many as 10,000 glucose monomers per molecule connected in long linear chains and arranged in a spiral form within the fiber. Chain length (average number of glucose monomers per molecule) contributes to fiber strength.Cotton can be altered by using chemical treatments or finishes. Mercerization (treating yarns or fabrics with sodium hydroxide [NaOH]) causes a permanent physical change. The fiber swells and creates a rounder cross section. Mercerization increases absorbency and improves the dyeability of cotton yarns and fabrics. Liquid ammonia is used as an alternative to several preparation finishes, especially mercerization. Fabrics treated with ammonia have good luster and dyeability. When these fabrics are treated to be wrinkle-resistant, they are not as stiff and harsh as mercerized wrinkle-resistant fabrics.

melt

For some synthetic polymers such as nylon and polyester, the polymer is formed, cooled, and broken into small pieces or chips. The chips are heated toy form a liquid melt, and the melt is used to form the fiber.

Bonds

Molecular chains are held close to one another by intermolecular forces called hydrogen bonds and van der Waals forces. The closer the chains are to each other, the stronger the bonds. Hydrogen bonding is the attraction of positive hydrogen atoms of one chain to the negative oxygen or nitrogen atoms of an adjacent chain. The van der Waals forces are weak bonds between atoms that are physically close together. Hydrogen bonding and van der Waals forces occur in the crystalline areas and help make crystalline polymers stronger than amorphous polymers.

Oriented

Molecular chains that are parallel to each other and to the fiber's lengthwise axis Highly oriented = highly crystalline But not all highly crystalline are highly oriented Highly oriented and crystalline fibers are strong and stiff. They do not stretch much or easily, but they recover from stretch quickly. They tend to be nonabsorbent and difficult to dye. Highly oriented and crystalline fibers include polyester, nylon, and aramid.

Degree of Polymerization

Number of molecules connected in chain

Fiber spinning process steps

Prepare a viscous dope (a thick solution) or a melt. Force or extrude the dope or melt through an opening in a spinneret to form a fiber. Solidify the fiber by coagulation, evaporation, or cooling.

Luster (Aesthetic Property)

Results from the way light is reflected by a surface (Figure 3.6). Shiny or bright fabrics reflect a great amount of light and are used in selected fashion instances or for safety reasons. Lustrous fabrics reflect a fair amount of light and are used in formal apparel and interiors. Matte, or dull fabrics reflect little light and are used most frequently for less formal looks in apparel and interiors. Silk fabrics are usually lustrous. Cotton and wool fabrics are usually matte. The luster of manufactured fibers can be varied during manufacturing. Fibers with high luster are referred to as bright fibers. (Bright is used here to describe luster, not color intensity.) Low-luster fibers are dull fibers. Medium-luster fibers are semibright or semidull. Yarn and fabric structure, and finish may change fabric luster.

Other cellulosic materials

Rush (stems of a marsh plant), sea grass from China and Vietnam, and maize or cornhusks are used in accent rugs because of their resistance to dry heat and soil. Rush and palm fiber seats are often used on wooden frame chairs for a natural look. Water hyacinth leaves are used to make accessories like baskets and hampers. Yarns made from paper (wood pulp) add interest and texture to wall coverings for interiors. Wooden slats and grasses are found in window treatments. Grasses are especially appealing for wall coverings; the variable weights, thicknesses, and textures add a natural look to interiors. They can be applied to any type of wall surface, treated to be flame retardant, and colored to match the decor. Cellulosic materials such as rush, sea grass, and wicker are important in interiors and are prized for their interesting texture and natural look. Wicker furniture is commonly made from tightly twisted paper yarns, rattan, and other such natural materials as sea grass, abaca (banana leaf), and raffia. Wall panels and wall coverings are produced from shredded straw and bark because of the interesting texture and shading produced by these materials

Recycled Wool

Scraps of new woven or felted fabrics that are garnetted (shredded) back to the fibrous state and reused. Shoddy wool comes from old apparel and rags that are cleaned, sorted, and shredded. Recycled wool may be blended with new wool before being respun and made into fabrics. usually not as durable as new wool because of wear and mechanical action

Smart textiles or smart fabrics

Sense and react to the environment or stimuli of an electrical, chemical, thermal, mechanical, magnetic, or other nature.

Sericulture

Sericulture is the production of cultivated silk, which begins when the silk moth lays eggs on a specially prepared paper. The cultivated silkworm is usually Bombyx mori, as such the silk can be called bombyx silk or mulberry silk. When the eggs hatch, the caterpillars, or larvae, are fed fresh, young mulberry leaves (Figure 5.24). After about 35 days and four moltings, the silkworms are approximately 10,000 times heavier than when hatched and are ready to begin spinning a cocoon, or chrysalis case. A straw frame is placed on the tray and the silkworm starts to spin the cocoon by moving its head in a figure eight. The silkworm produces silk in two glands and forces the liquid silk through spinnerets, openings in its head. The two strands of silk are coated with a water-soluble protective gum, sericin. When the silk comes in contact with the air, it solidifies. In 2 or 3 days, the silkworm will spin approximately 1 mile of filament and will completely encase itself in a cocoon (Figure 5.25). The silkworm then metamorphoses into a moth. Usually the silkworm is killed (stifled) with heat before it reaches the moth stage.

Short Staple Cottons (3 Types)

Short-staple cottons, also known as tree cotton, Gossypium arboreum and Gossypium herbaceum, are less than ¾ inch in length and are only commercially cultivated in India and Pakistan.

Wild Silk

Silk produced by any other species of moth than the bombyx mori

Schappe

Silk yarns and fabrics derived from waste silk

Waste Silk

Silk you can't use for reeling

End use

The application or function for which a textile is designed or for which it is ultimately used.

Wool cuticle

The cuticle consists of an epicuticle and a dense, nonfibrous layer of scales. The epicuticle is a thin, nonprotein membrane that covers the scales. This layer gives water repellency to the fiber but is easily damaged by mechanical action. In fine wools, the scales completely encircle the shaft and each scale overlaps the bottom of the preceding scale, like parts of a telescope. In medium and coarse wools, the scale arrangement resembles shingles on a roof or scales on a fish (Figure 5.8). The free edges of the scales project outward and point toward the tip of the fiber. The scales contribute to wool's abrasion resistance and felting property, and they can irritate or prickle sensitive skin.

Physical Structure of Wool

The length of Merino wool and other fine wool fibers ranges from 1½ to 5 inches, depending on the animal and the length of time between shearings. Long, fine wool fibers, used for worsted yarns and fabrics, have an average length of 2½ inches. Worsted refers to a compact yarn and implies longer fibers and greater uniformity of fiber length after it undergoes a combing process. The shorter fibers, which average 1½ inches in length, are used in woolen fabrics. Woolen describes a softer and more loosely twisted yarn and implies shorter, less uniform in length, and less parallel fibers. Some sheep breeds produce coarse, long wools (5 to 15 inches in length) used in specialty and hand-crafted fabrics. When present, the medulla is a microscopic honeycomb-like core containing air spaces that increase the insulating power of the fiber. It may appear as a dark area when seen through a microscope, but is usually absent in fine wools. The cortex is the main part of the fiber. It is made up of long, flattened, tapered cells with a nucleus near the center. In natural-colored wools, the cortical cells contain melanin, a colored pigment. The cortical cells on the two sides of the wool fiber react differently to moisture and temperature. These cells are responsible for wool's unique 3D crimp, in which the fiber bends back and forth and twists around its axis . Crimp may be as high as 30 per inch for fine Merino wool to as low as 1 to 5 per inch for low-quality wool.

Polymerization

The process by which the chains of monomers, or polymers, are created

Spinning solution or dope

The raw material is a natural product such as cellulose or protein, or it is a synthetic polymer. These raw materials are dissolved in liquid chemicals and made into thick solutions called

Grades of Cotton

There are 39 grades of cotton. Grade refers to the color of the fiber and the absence of dirt, leaf matter, seed particles, motes or dead fibers, and tangles of fiber called neps. Mote fibers do not absorb dyes, lower fiber quality, and cause defects in fabrics. The best-quality grade is lustrous, silky, white, and clean. The predominant grade of cotton produced in the United States is strict low-middling cotton. Strict in this case means better than. Strict low-middling cotton is most often used in mass-produced cotton goods and in cotton/synthetic blends. This grading system is used primarily for the creamy white fibers that dominate the market. Color is described as white, light-spotted, spotted, tinged, or yellow. Color is also described in terms of lightness to darkness: plus, light gray, and gray. This factor is a combination of grayness and the amount of leaf bits present in white cotton grades.

Reeling

To obtain filament silk, the cocoons that have been stifled are sorted for fiber size, fiber quality, and defects, then brushed to find the outside ends of the filaments. Several filaments are gathered together and wound onto a reel. This process, referred to as reeling, is performed in a manufacturing plant called a filature.

Yak

Yak fiber is produced by a large ox found in the Himalayan mountain region of Tibet and Central Asia, with some small herds in the United States (Figure 5.23). The yak produce fiber that ranges from very fine to very coarse. The outercoat fibers can measure from 4 ½ to 15 inches long, and are spun for ropes, cords, tent covers, and durable rugs. The soft, fine undercoat fibers, are short, but smooth and lustrous, and may be used in apparel such as scarves and shawls. Yak fiber is used in the international market because it is mixed with the much more expensive cashmere to extend its use and lower the cost. It is coarser than cashmere and often dark brown, black, or golden in color.

Drape (Aesthetic Property)

a fabric characteristic, is the way a fabric falls over a 3D form like a body or table. Fine fibers produce a softer drape than coarse fibers. Fibers influence fabric drape to a degree, but yarns and fabric structure are usually more important in determining drape. Chiffon is soft and free flowing, chintz falls in graceful folds, and gabardine is stiff and heavy. As such, chiffon is often used in formal dresses, chintz in decorative furnishings, and gabardine in women and men's suits and overcoats.

Scroop

a natural rustle, which can be increased by treatment with an organic acid such as acetic or tartaric acid. Silk can be dyed and printed in brilliant colors.

Scutching

a process that breaks or crushes the outer covering when the stalks are passed between fluted metal rollers. Most of the fibers are separated from one another, and the short and irregular fibers are removed by hackling, or combing. This final step removes any remaining woody portion and arranges the fibers in a parallel fashion.

Qiviut

a rare and luxurious fiber, is the underwool of the domesticated musk ox (Figure 5.18). A large musk ox provides about 6 pounds of wool each year. The fiber can be used just as it comes from the animal, for it is protected from debris by the long guard hairs and has low lanolin content. Qiviut resembles cashmere in hand and texture but is much warmer. The fleece is not shorn but is shed naturally and is removed from the guard hairs as soon as it becomes visible. Producers in Alaska and Canada raise musk ox and harvest the fiber. Qiviut is expensive and used to produce handcrafted items by fiber artists, Inuit, and other American Indian people.

Sorting Wool

a single fleece is separated into sections of fibers of different quality. The best-quality wool comes from the sides, shoulders, and back; the poorest wool comes from the lower legs

2 Parts of a Manufactured Fiber:

a skin and a core.

Spinneret

a small thimblelike nozzle made of platinum or stainless steel

Felting

a unique and important property of wool, is based on the structure of the fiber. Under mechanical action—combining agitation, friction, and pressure with heat and moisture—adjacent wool fibers move rootward and the scale edges interlock. This prevents the fiber from returning to its original position and results in shrinkage, or felting, of the fabric

Wool

a widely used natural protein fiber, but production rates have decreased and costs have increased. fleece is removed from the sheep once a year (spring) with shears in one long stroke however you can also remove the hair by using food additives/injections - protein: keratin - contains more amino acid types w/ larger molecular side groups - wool molecule is bigger and bulkier - better resiliency because wool is more likely to bond with side groups - contains sulfur, more prone to insect damage

Filaments

are long, continuous fiber strands of indefinite length, measured in miles or kilometers. They may be monofilament (one filament) or multifilament (a number of filaments). Filaments may be smooth or bulked (crimped in some way), as shown in Figure 3.2. Smooth filaments are used to produce silklike fabrics; bulked filaments are used in more cottonlike or woollike spun yarn fabrics. Silk fiber woven into crepe de chine, acetate fiber woven into taffeta fabric, and polyester fiber woven into gabardine fabric are examples of filament yarn fabrics

Manufactured (or man-made) Fibers

are made into fiber form from chemical compounds produced in manufacturing facilities. Manufactured fibers may be made from cellulosic, protein, or mineral sources or produced from synthetic polymers.

Natural Protein Fibers

are of animal origin: wool and specialty wools are the hair and fur of animals, and silk is the secretion of the silk caterpillar. Protein fibers have some common properties because of their similar chemical composition considered luxury fibers today ex. Silk, vicuña, cashmere, and camel hair

Filament fibers

are spun from spinnerets with 350 holes or fewer. When these fibers are grouped together and slightly twisted, they form a filament yarn

Natural Fibers

are those that are in fiber form as they grow or develop and come from animal, plant, or mineral sources

retting

bacterial rotting process for bast fibers, Fiber quality can be greatly impacted by the retting process. Retting can be done in the fields (dew retting) or in stagnant ponds, pools, or tanks (water retting), where the temperature and bacterial count can be carefully controlled with special enzymes or with chemicals such as sodium hydroxide. Chemical retting is much faster than any other method. However, extra care must be taken or the fiber can be irreversibly damaged. Retting can create problems with water quality if the retting water is released directly into streams or lakes. Dew retting is done in many areas because of its minimal environmental impact.

Traceback

barcodes enable customers to trace where their product and fibers (wool) were made and how they were made (if sustainable or not)

Texture (Aesthetic Property)

describes the nature of the textile's surface. It is identified by both visual and tactile senses. Textiles may have a smooth or rough texture. Natural fibers tend to give a fabric more texture than manufactured fibers because of the variations inherent in the structure of natural fibers. Yarns, finishes, and fabric structure also greatly impact texture. Consider the differences in texture among products made out of cotton but woven into flannel sheets, denim jeans, or a terry cloth hand towel.

Surface Contour

describes the outer surface of the fiber along its length. Surface contour may be smooth, serrated, striated, or rough, and it affects luster, hand, texture, and apparent soiling of the fabric. Surface contour can make fabrics seemingly more or less comfortable and easier or more difficult to clean.

Care

describes the treatment required to maintain a textile product's original appearance and cleanliness. What is the item's recommended care procedure? Is the care procedure appropriate to maintain the product's look? Are these recommendations appropriate considering its end use, cost, and product type? Is the care reasonable for the product and target market?

Llama and Alpaca

domesticated animals of the South American branch of the camel family (Figures 5.21 and 22). The fiber from their coats is 8 to 12 inches in length and is noted for its softness, fineness, and luster. Two breeds of alpaca are the suri, which have smooth distinct locks that are curly, twisted, or straight, and the huacaya with a crimpy, fluffly fleece that is soft and smooth. There are up to 22 shades of color, including white to light fawn, light brown, dark brown, gray, and black. Because alpaca is soft, it is often used for apparel, handcrafts, and rugs. However, it is more difficult to dye than most other specialty wools. For this reason, it is often used in its natural colors. Scales are less pronounced, so felting is not as big a problem as with other wools. Its soft hand, beautiful luster, and good draping characteristics are appreciated by fashion designers. Llama is coarser and most often used for coats, suitings, ponchos, and shawls. As with wool, fibers from the younger llama and alpaca are finer and softer.

Cotton Classification

done by hand and by machine HVI (high-volume instrument) systems. Fiber characteristics, including staple length and color of the cotton from the bale, are compared with standards prepared by the U.S. Department of Agriculture. Pricing and end use of the cotton is largely determined by the length and the grade of the cotton. Cotton classification describes the quality of cotton in terms of staple length, grade, and character. Fiber-length classifications for cotton include very-short-staple cotton (less than 0.25 inch), short-staple cotton (0.25 to 0.94 inch), medium-staple cotton (0.94 to 1.13 inches), ordinary long-staple cotton (1.13 to 1.38 inches), and extra-long-staple cotton (1.38 inches). Staple length is based on the length of a representative bundle of fibers from a bale of cotton. There are 19 staple lengths, ranging from less than 13/16 inch to 1⅛ inches and beyond. A sample classified as 15/32 inch is likely to have fibers ranging in length from ⅛ inch to 13/16 inches, as shown in

Life Cycle Impact

examines the way the production, use, care, and disposal of a product affects the environment and the people involved with the product. How has the production of this item changed the environment and the people involved in its production? How will its recommended care alter the environment? Can this product, its components, or its packaging materials be recycled? Do the product or its packaging contain any recycled materials? Have the product or its components been evaluated for environmental concerns and sustainability? Can the individuals or company producing this product earn a living or make a profit? Are the fibers rapidly renewable without concentrating their impact within one segment of the agricultural or manufacturing segment?

race to the bottom

experienced in cotton business where companies and countries tried to compete with each other by cutting wages and living standards for workers, and the production of goods is moved to the places that have the lowest wages and production costs.

lint

fibers that are pressed into bales weighing 480 pounds each and sold to spinning mills or exported

Environmental Concerns

focus on the impact that the production, use, care, or disposal of a textile has on the environment

Specialty Wool

from goat, rabbit and camel families less is produced and is more expensive 2 kinds: 1) coarse, long outer hair 2) soft, fine undercoat

Quality

generally refers to the sum total of product characteristics such as appearance, end use, performance, material interactions within the product, consistency among identical products, and freedom from defects in construction or materials.

Hollow or multicellular fibers

imitate the air cells of some animal hair, which provides insulation in cold weather, and the hollow feathers of ducks, which produce buoyancy in water. Air cells and hollow filaments in manufactured fibers are made by adding gas-forming compounds to the spinning solution, by injecting air as the fiber forms, or by modifying the shape of the spinneret holes. For example, when the spinneret hole is in a C shape or as two half circles, the dope flows slightly on extrusion so that the perimeter closes up and the center remains hollow.

Fiber Structure

includes the physical aspects of fibers like length, diameter, shape, contour, crimp, and components and the chemistry of the fiber including chemical composition and arrangement of the molecules.

Denier per filament

is a way of identifying fiber size; it is often used when describing or specifying yarns. Dpf is calculated by dividing the yarn size by the number of filaments: 40 denier yarn/20 filaments = 2 denier per filament. Fine cotton, cashmere, or wool is 1 to 3 denier; average cotton, wool, or alpaca is 5 to 8 denier; and carpet wool is 15 denier. Most apparel fibers range from 1 to 7 denier, although much smaller fibers are also available. Carpet fibers may range from 15 to 24 denier. Technical fibers exhibit the broadest range, from less than 1.0 to several thousand, depending on the end use. For example, fibers used for weed trimmers and towropes are much larger than those used for absorbent layers in diapers or for fabrics to polish lens for glasses and microscopes.

Dupioni Silk

is another type of silk that results when two silkworms spin their cocoons together. The yarn is irregular in diameter with a thick-and-thin appearance. It is used in such linenlike silk fabrics as shantung.

extrusion

is forcing or pumping the dope or melt through the spinneret's tiny holes.

Coir

is obtained from the fibrous mass between the outer shell and the husk of the coconut (Cocos nucifera). It is sometimes sold as coco fiber. The long, curly fibers are removed by soaking the husk in saline water. Coir, which is very stiff, is naturally cinnamon-brown. It can be bleached and dyed. It has good resistance to abrasion, water, and weather. Available from Sri Lanka, coir is used for indoor and outdoor mats, rugs, floor tiles, and brushes. Its stiff, wiry texture and coarse size produce fabrics whose weave, pattern, or design is clearly visible. These floor textiles are extremely durable and blend with interiors of many styles.

Kapok

is obtained from the seed of the Java kapok (silk cotton) tree (Eriodendron anfractuosum) or the Indian kapok tree (Bombax malabarica). The fiber is lightweight, soft, hollow, and very buoyant, but it quickly breaks down. The fiber is difficult to spin into yarns, so it is used primarily as fiberfill in some imported items from Java, South America, and India . Researchers in India are studying ways of blending kapok with cotton for apparel uses.

bast fiber (ex. flax)

is obtained from the stem and root of the plant

Camel Hair

is obtained from the two-humped Bactrian camel (Figure 5.20). Major producers of camel hair include China, Mongolia, Iran, Afghanistan, Russia, New Zealand, Tibet, and Australia. Camel hair is an excellent insulator. The hair is collected as it is shed or sheared from the animals. A camel produces about 5 pounds of hair a year.Because camel hair gives warmth without weight, the finer fibers are valued for apparel. They are often used in blends with sheep's wool, which is dyed the tan color of camel hair. Camel hair is used in coats or jackets, scarves, and sweaters. Blankets of camel hair and wool are also available. The fiber from the one-humped Dromedary camel is coarser and used primarily for ropes and other technical products.

Flax

is one of the oldest documented textile fibers. Fragments of linen fabric have been found in prehistoric lake dwellings in Switzerland; linen mummy wraps more than 3,000 years old have been found in Egyptian tombs. The linen industry flourished in Europe until the 18th century. With the invention of power spinning, cotton replaced flax as the most important and widely used fiber. Today, flax is a prestige fiber as a result of its limited production and relatively high cost. The term linen refers to fabric made from flax, but, that term may be misused when it refers to fabrics of other fibers made of thick-and-thin yarns with a heavy body and crisp hand. Irish linen always refers to fabrics made from flax. (Because of its historic wide use in sheets, tablecloths, and towels, the word linen is used to refer to table, bed, and bath textiles.) The unique and desirable characteristics of flax are its body, strength, durability, low pilling and linting tendencies, pleasant hand, and thick-and-thin texture. The main limitations of flax are low resiliency and lack of elasticity.

Cover (Aesthetic Property)

is the ability of a fiber to conceal or protect. Fibers that are opaque, like cotton, can be used to produce relatively lightweight fabrics like batiste such that they provide cover, yet are not too heavy in weight.

Tenacity/tensile strength (Durability Property)

is the ability of a textile to withstand a pulling force

Abrasion Resistance (Durability Property)

is the ability of a textile to withstand the rubbing it gets during use (Table 3.3). Abrasion is measured by rubbing a textile against a surface and measuring the change in strength or appearance. Abrasion can occur when the textile is fairly flat, such as repeated walking on a rug creating visible wear and tear. Edge abrasion can occur when the textile is folded, as when a pant hem rubs on a sidewalk and the fabric is abraded. Flex abrasion can occur when the textile is moving and bending, as in shoelaces that wear out where they are laced through the shoe.

light/sun resistance

is the ability to withstand degradation from natural or artificial light. Exposure to light may damage fibers. The energy in light, especially in the ultraviolet region of the spectrum, causes irreversible damage to the chemical structure of the fiber. This damage may appear as a yellowing or color change, a slight weakening of the fabric, or, eventually, the complete disintegration of the fabric (see Table 3.3). Fibers with good light resistance are used where exposure to light, especially sunlight, is high. For example, acrylic is often used in awnings because of its high light resistance. Tenacity is measured before and after exposure to light. A loss in strength indicates ultraviolet damage to the fiber.

Cost

is the amount paid to acquire, use, maintain, and dispose of a product. Additional factors that should be considered include how much it will cost to care for this product during its lifetime and the product's inherent attributes.

Parent Fiber

is the fiber in its simplest, unmodified form. It is often sold as a commodity fiber by generic name only, without benefit of a trade name. Other terms for parent fiber include regular, basic, standard, conventional, or first-generation fiber.

Pilling (Durability Property)

is the formation of balls of fiber on the fabric surface. Pilling most often occurs when fibers of differing abrasion resistance, such as cotton and polyester, are combined into one fabric. With abrasion, short pieces of the less-resistant cotton break off and become entangled with the more abrasion-resistant polyester, forming little balls of fiber on the surface. These little pills are not only unattractive but can be uncomfortable as well.

Angora

is the hair of the Angora rabbit produced in Europe, Chile, China, and the United States (Figure 5.19). It is harvested up to four times a year by plucking or shearing. Fiber yield and quality vary with the rabbit and its health and breed, and ranges from 8 to 30 oz. Of the four breeds of Angora rabbits, the two most common types are English and French. English Angoras produce a fine silky fiber; French Angoras produce a coarser fiber. The white or naturally colored fiber is very fine (13 microns), fluffy, soft, slippery, and fairly long. Angora does not take dye well and usually has a lighter color than other fibers with which it is blended. It is often blended with wool to facilitate spinning because the slick fiber has poor cohesiveness. Angora is used in apparel such as sweaters and suitings and in knitting yarn. If a label states rabbit hair, this means the fiber is from a common rabbit, not an Angora rabbit. Rabbit hair is often used to make felt for hats, but it is too short to make into yarns for woven or knit fabrics.

Textile complex

is the international mix of related industries that provide soft goods for the world's population. While many dimensions of the textile complex are not evident to the average individual, huge segments of the world population are involved in the development, engineering, design, production, evaluation, marketing, and transportation of textiles and textile products.

Tussah Silk

is the most common type of wild silk. It is coarser, darker, and cannot be bleached. Hence, white and light colors are not available in tussah silk. Tasar is a type of wild silk from India. Some fabrics are sold simply as wild silk. The term raw silk is sometimes used incorrectly to describe these fabrics.

Hand (Aesthetic Property)

is the way a textile feels to the skin. Hand is often described using adjectives such as warm or cool, bulky or thin, and slick or soft. Hand may be evaluated by feeling a fabric between the fingers and thumb. Both human assessment and instrument measures are used to determine suitability for an end use. Hand is important for designers and consumers. Imagine walking into an area with bolts of fabric on counters, garments on racks, or examining swatch books of drapery and upholstery fabrics and not touching anything!

Tex

is the weight in grams of 1,000 meters of fiber or yarn. Staple fiber is sold by denier and fiber length; filament fiber is sold by the denier of the yarn or tow.

Denier (manufactured fibers)

is the weight in grams of 9,000 meters of fiber or yarn. When used to describe a fiber, denier refers to the fineness or coarseness of the fiber—small numbers describe fine fibers; large numbers describe coarse fibers.

Trilobal Shape

is widely used with nylon and polyester fibers (Figure 6.6). It is spun through a spinneret with three triangularly arranged slits. Fabrics made with trilobal fibers have a beautiful silklike hand, subtle opacity, soil-hiding capacity, built-in bulk without weight, heightened wicking action, silklike sheen and color, crush resistance in heavy deniers, and good textured crimp.

Cashmere

produced by the small cashmere goat, fibers are white-brown to grey Has an outer coat of long, coarse hair and an inner coat of down. Combed by hand from the animal during the molting season. In dehairing, the coarse hair is separated from the fine fibers (13 to 18 microns, must not exceed 19 microns). The downy fine fibers make up only a small part of the fleece, usually about one-half pound per goat. The fiber is solid, with no medulla and with fine scales. Cashmere is graded by color, tensile strength, and freedom from contamination with other fibers or plant residue. Cashmere is used for sweaters, coats, suits, jackets, loungewear, and blankets. Fabrics are warm, buttery in hand, and have beautiful draping characteristics. Cashmere is more sensitive to chemicals than wool. Pashmina, an Indian word for cashmere, is a fine fiber originally produced in parts of northern India, Kashmir, and Pakistan. However, the term pashmina is not a labeling term recognized by the FTC. Some manufacturers use the term pashmina to describe a blend of cashmere and silk, still others use the term completely incorrectly to describe a scarf or shawl made of the manufactured fiber acrylic. Consumers should take great care in purchasing and caring for these mismarked goods. Cashmere is sometimes mistaken for shahtoosh, an illegal fiber harvested from slaughtered Tibetan chiru antelopes. The chiru is on the endangered species list. Sometimes, cashmere is blended with less expensive sheep's wool. When labels indicate a blend, no legal problem exists. However, this is a fraudulent practice when the label does not indicate that the product is a blend.

Organic Cotton

produced following state fiber-certification standards on land where organic farming practices have been used for at least three years. No synthetic commercial pesticides or fertilizers are used in organic farming. Integrated pest management programs help decrease use of pesticides. The BASIC (biological agricultural systems in cotton) program uses approximately 70% fewer pesticides and is an alternative to organic cotton.

Transition Cotton

produced on land where organic farming is practiced, but the three-year minimum has not been met.

Milkweed

produces a soft, lustrous, hollow-floss seed hair fiber resembling kapok. Milkweed has been used for fiberfill in comforters, personal flotation devices, and upholstery. It is very difficult to spin into yarns because it is so weak, smooth, and straight. Milkweed is also known as silkweed fiber and asclepias cotton.

Momme

pronounced like mummy and abbreviated mm, describes the weight of the silk. One momme (momie or mommie) weighs 3.75 grams. Most silk fabrics are produced in several weights. Higher numbers describe heavier fabrics. Other terms such as habutai or crepe describe the yarn and fabric structure. Silk fabrics are often graded for their degree of evenness, fiber or yarn size, and freedom from defects. Grade A refers to the highest grade, only about 10% of the silk produced.

hygroscopic

protein fibers are hygroscopic, which means they absorb moisture without feeling wet

Vicuña and guanaco

rare wild animals of the South American camel family. In the past, the animals were killed to obtain the fiber. Now, they are sheared in a manner similar to that of sheep. Vicuña and guanaco are protected animals. Vicuña is one of the softest, finest (13 micron), rarest, and most expensive of all textile fibers. The fiber is short, very lustrous, and light cinnamon in color. Research is under way to produce genetic crosses of alpaca and vicuña. Currently, vicuña are classified as a threatened species. The Peruvian government labels products containing vicuña to guarantee that the animals were captured, sheared alive, released, and will not be sheared again for 3 years. A large portion of the profit from the sale of vicuña is returned to the villagers. However, poaching continues to be a problem. Products made from vicuña and guanaco are quite expensive, and include suitings, coats, and jackets.

Assortment

refers to a group of fabrics that share a commonality of design, structure, or color

Elongation (Durability Property)

refers to the degree to which a fiber may be stretched without breaking. It is measured as percent elongation at break (see Table 3.4) by measuring the change in length and comparing that to the original length. Elongation should be considered in relation to elasticity. Highly oriented and highly crystalline fibers do not elongate much when a force is applied. However, when that force is released, they recover quickly to their original length or very close to their original length. Aramid, used in ballistic vests, is a fiber that has very low elongation.

generic name

refers to the family of manufactured or synthetic fibers that have a similar chemical composition, are based on fiber chemistry, and are approved by the Federal Trade Commission

Kemp

refers to the heaviest and coarsest of all hair fibers, are often quite short, and don't display dye colors very well

Fiber Crimp

refers to the waves, bends, twists, coils, or curls along the length of the fiber. Fiber crimp increases cohesiveness, resiliency, resistance to abrasion, stretch, bulk, and warmth. Crimp increases absorbency and skin-contact comfort but reduces luster. Fibers with lots of crimp like wool are warmer than fibers with little crimp like cotton. Crimp helps trap air within the fabric and next to the skin, making the fabric warmer. Inherent crimp occurs in wool. Inherent crimp also exists in an undeveloped state in bicomponent manufactured fibers in which it is developed in the fabric or the garment (such as a sweater) with heat or moisture during finishing. The size and frequency of wool's crimp is dependent upon where the fiber grows on the animal, environmental factors, the breed of sheep, and even the animal's age.

leaf fiber (ex. sisal)

removed from the veins or ribs of a leaf.

Staple Fibers

short fibers measured in inches or centimeters. They range in length from less than 2 to 46 cm (0.5 to 18 inches). Except for silk, all of the natural fibers are available only in staple form. Staple fibers are used to produce spun yarn fabrics. Cotton woven into sateen as used in sheets, shirts, and blouses is an example of a spun yarn fabric.

Product Development

the design and engineering of a product so that it has the desired serviceability characteristics, appeals to the target market, can be made within an acceptable time frame for a reasonable cost, and can be sold at a profit. Product development encompasses a range of activities and differs widely by companies and segments of the global textile complex. The product development process involves many areas of specialized knowledge. This includes knowing which product characteristics appeal to specific target markets to comprehending how to produce the item so that it meets consumers' needs. Important factors for successful product development include understanding processes, people, and things including product innovation and management, consumers, and textile materials.

Silk

the secretion of the silk caterpillar, produced by moth larvae, no cross sections in formation - protein: fibroin - contains less amino acid types w/ smaller molecular side groups - does not contain sulfur - luxury fiber

cotton gin

to separate the fibers and the seeds. In a saw gin, the whirling saws pick up the fiber and carry it to a knifelike comb, which blocks the seeds and permits the fiber to be carried through

Solubility Tests

used to identify the manufactured fibers by generic class and to confirm identification of natural fibers. Two simple tests, the alkali test for wool and the acetone test for acetate, are described in Chapters 5 and 7, respectively.

bicomponent fiber

wool has two different cell types or two components with slightly different properties in the cortex. The ratio of these cells influences the amount of crimp in the wool fiber and its affinity for dye. This bicomponent nature is best illustrated by describing how wool reacts to moisture. One side of the fiber swells more than the other side, decreasing the fiber's natural crimp. When the fiber dries, the crimp returns. Wool can be compared to a giant molecular coil spring. It has excellent resiliency when the fiber is dry and poor resiliency when it is wet. If dry wool fabric is crushed, it tends to spring back to its original shape when the crushing force is released. Wool can be stretched up to 30% longer than its original length. Recovery from stretching is good, but it takes place more slowly when the fabric is dry. Since steam, humidity, and water hasten recovery, wool items lose wrinkles more rapidly when exposed to a steamy or humid environment.

Virgin Wool

wool that has never been processed, "wool" implies this