The final part of my textiles review covers regenerated fibers. I imagine my textiles reviews are not as exciting to read as are my normal blog entries, but writing them was quite helpful to me. The test was yesterday. I found it easy. I am sorry if you do not care for these reviews, but I plan to write more of them next time a test rolls around. Fortunately that will not be for a while, so I may now return to my normal irreverent blogging.
Manufactured fibers are formed into fibers from chemical compounds. They do not exist in fiber form without human intervention. Manufactured fibers may be regenerated or synthetic. Regenerated fibers are produced from naturally occurring polymers that do not occur naturally as fibers. Regenerated fibers are made from cellulose (plant) or protein (plant or animal). Synthetic fibers are made from polymers that do not occur naturally.
The Federal Trade Commission gives fibers generic names based on fiber chemistry. Manufacturers may also use trade names for the fibers they produce.
Fiber production
The process of producing a manufactured fiber is called spinning. Whether fibers are regenerated or synthetic, the spinning process is the same. The only significant differences occur in the production of the solution from which the fiber is made. Raw materials are made into a spinning solution (dope) by dissolving them in chemicals. I do not have the necessary knowledge of chemistry to understand the solution production process, and information about that process is not taught in my class, so I will speak of it no more. Fiber manufacture follows three steps:
1. Prepare a dope or melt
2. Extrude the dope or melt through a spinneret to form a fiber
3. Solidify the fiber by coagulation, evaporation, or cooling.
The spinneret is like a showerhead through which the dope is forced. The size and shape of the holes in the spinneret determine the size and shape of the fiber.
Manufactured fibers may be used in filament or staple form. Filament yarn is made by twisting filament fibers together. Filament tow is a rope of thousands of untwisted filament fibers. It is cut to make staple fibers. The fibers may be crimped.
There are three basic methods of fiber spinning:
Wet spinning: Raw material is dissolved by chemicals to produce a dope. The fiber is spun into a chemical bath where it solidifies. Wet spinning is the oldest and most complex method of fiber manufacture. The solvent and chemical bath are hazardous materials that must be recovered. Wet spinning can be used to produce acrylic, lyocell, rayon, and spandex. Wet spinning is rarely used.
Dry spinning: Resin solids are dissolved by chemicals to produce a dope. The fiber is spun into warm air where evaporation of the solvent causes the fiber to cool and solidify. The solvent must be recovered, but without the chemical bath there are fewer hazardous materials than in wet spinning. Dry spinning can be used to produce acetate, acrylic, modacrylic, and spandex.
Melt spinning: Resin solids are melted to produce a dope. The fiber is spun into air where it cools and solidifies. It is the cheapest method of fiber production, and there are no solvents to be recovered. It can be used to produce nylon, olefin, polyester, and saran. Regenerated fibers are not produced by melt spinning.
Fiber modifications
Every step of the fiber manufacture process can be precisely controlled to produce uniform fibers with specific characteristics.
Spinneret modifications: The size and shape of spinneret holes can be adjusted to produce fibers with specific dimensions. Hollow fibers may be created by adding gas forming compounds to the dope, by injecting air into the fiber as it forms, or by altering the shape of the spinneret hole. Hollow fibers are good insulators.
Molecular structure and crystallinity modifications: The molecular structure and the degree of crystallinity of a fiber contribute to its properties. These can be altered in the manufacture process by a controlled stretching of the fiber after it exits the spinneret or by selecting specific compounds used to produce the polymers. High tenacity fibers may be produced by stretching the fibers to line up the molecules and /or by chemical modification of the polymer to increase the degree of polymerization. I am not really sure what that all means. I never liked organic chemistry. The molecules are too big. I prefer physics where all the really exciting stuff happens in spaces smaller than an atomic nucleus.
Dope additives: Chemicals may be added to the dope to alter the fiber’s properties. Dyes may be added to color a fiber. Solution dyed fibers retain color better than fibers dyed after they are produced. Dye-accepting chemicals may be added to make a fiber more dyeable. Whiteners may be added to make fibers look whiter and resist yellowing. Delusterants may be added to reduce a fiber’s luster.
Modifications in fiber spinning: Crimp may be added to manufactured fibers by altering the way the fiber cools and solidifies. Filament fibers can be cut to create staple fibers.
Bicomponent fibers: Two polymers may be combined in a single fiber. Bilateral fibers are spun with two polymers side by side. Core-sheath fibers have one polymer encircled by another. The different polymers may react differently to heat and moisture, or each may have specific characteristics that are desired in the finished fiber.
Regenerated fibers
Regenerated fibers are produced from naturally occurring polymers that do not occur naturally as fibers. Cellulose and protein may be uses to produce regenerated fibers.
Rayon, lyocell, acetate, bamboo, and PLA are regenerated cellulosic fibers.
Azlon is the generic name for all regenerated protein fibers.
Rayon
Rayon was the first manufactured fiber. The earliest form of rayon was invented in 1846, but it was highly explosive. Commercial production of viscose rayon began in the U.S. in 1911. Rayon is produced with the wet spinning method.
There are three types of rayon: Viscose rayon, cuprammonium (cupra), and high wet modulus (HWM) rayon. Viscose was the first type of rayon commercially produced, and HWM is the newest. Cupra is sold with the trade name Bemberg®. HWM is sold with the generic name polynosic and the trade name ModalTM.
Physical structure of rayon
Rayon can be either staple or filament. The fiber has lengthwise lines called striations. It has a serrated or indented circular cross section. This is caused by the fiber collapsing in on itself during coagulation from loss of the solvent. Cupra and HWM have a rounder cross section than viscose.
Properties of rayon
Aesthetics: Rayon can be produced to look like cotton, flax, wool, and silk.
Durability: Rayon is a low tenacity fiber that loses up to 50% of its strength when wet. HWM rayon is stronger than cupra, and cupra is stronger than viscose. Viscose has a breaking elongation of 8% to 14%. HWM rayon has a breaking elongation of 9% to 18%. Rayon may be permanently damaged by water.
Comfort: Rayon has a soft, smooth hand. It is highly absorbent, a good conductor of heat, and it does not build up a static charge.
Appearance retention: Rayon has low resiliency and dimensional stability. Viscose rayon may stretch or shrink. HWM rayon has better dimensional stability; it is less likely to stretch or shrink.
Care: Viscose rayon should be dry-cleaned. Cupra and HWM rayon may be machine washable; read the care label. Rayon is resistant to heat and may be ironed with high temperatures. Rayon may be damaged by silverfish and mildew, so it should be stored dry.
Environmental impact: Most rayon is produced from wood pulp. The fiber is biodegradable, but it cannot degrade if it is placed in a landfill. The wet spinning process uses large quantities of chemicals that may contribute to air and water pollution. Cupra is no longer produced in the U.S. because manufacturers were unable to comply with water and air quality requirements.
Lyocell
Lyocell was introduced in the early 1990s. It was originally sold as a type of rayon, but it differs from rayon enough that it now has a separate generic classification. Lyocell is sold with the trade name Tencel®
Physical structure of lyocell
Lyocell fibers can be staple or filament. The fibers have a smooth surface and round cross section.
Properties of lyocell
Aesthetics: The luster, drape, and texture of lyocell can be varied. Lyocell imitates the aesthetics of the natural cellulosic fibers, but it most closely resembles cotton. Lyocell fibers may pill.
Durability: Lyocell is the strongest regenerated cellulosic fiber. Its breaking tenacity is 4.8 to 5.0 g/d dry and 4.2 to 4.6 g/d wet. Lyocell has good abrasion resistance and poor elongation.
Comfort: Lyocell has a soft, smooth hand. It resembles cotton. It has excellent absorbency and poor thermal retention.
Appearance retention: Lyocell has moderate resiliency; it wrinkles, but not as badly as rayon. Lyocell has moderate dimensional stability. It may shrink, but not too badly.
Care: Lyocell may be machine washed on gentle cycle or dry cleaned. Read the care label. It may be ironed with high heat. It may be damaged by mildew and insects.
Environmental impact: Lyocell is produced with the wet spinning method, but the solvents are recycled so hazardous waste is not produced. The chemicals used to produce lyocell are less harmful than those used to produce rayon. Lyocell is biodegradable, but if it is placed in a landfill it will not degrade.
Acetate
Acetate was introduced in the U.S. in 1924
Physical properties of acetate
Acetate fibers can be staple or filament. Acetate typically has a lobular cross-sectional shape and lengthwise striations, but the shape of the fiber can be altered in the spinning process. Acetate is thermoplastic; it melts in high heat. Acetate dissolves in acetone.
Properties of acetate
Aesthetics: The aesthetic properties of acetate are excellent. It has high luster, good drape, and smooth hand and texture. It is often used to make fabrics for which good appearance is more important that durability and ease of care.
Durability: Acetate is not a durable fiber. Its dry breaking tenacity is 1.2 to 1.4 g/d, and it is slightly weaker when wet. Acetate has low abrasion resistance and elongation. Acetate is resistant to mildew and moths.
Comfort: Acetate has a smooth, soft, but slightly clammy hand. It has moderate absorbency. It builds up a static charge. It is a moderate insulator.
Appearance retention: Acetate has poor appearance retention. It has poor resiliency and elastic recovery, and moderate dimensional stability. It may shrink. Acetate may experience fume fading – its color changes. This may be prevented with solution dyeing.
Care: Acetate should be dry-cleaned. It melts at high temperatures, so it may only be ironed on low heat.
Other regenerated fibers
Bamboo is a type of rayon that uses bamboo as the source of cellulose. It contains no bamboo fibers. In the past few years bamboo has been marketed as an environmentally friendly fabric, but the claims were unsubstantiated. The FTC has recently taken action against manufactures of bamboo rayon barring them from making deceptive claims about the fabric. The FTC does not recognize “bamboo” as a generic name for bamboo based rayon.
PLA (polylactic acid) is a regenerated cellulosic fiber made from cornstarch. The FTC approved it as a generic fiber in 2002. It is sold with the trade name Ingo®. We had some PLA in lab. It seems great. I would like to find some of it to play with.
SoySilk® is a type of azlon. It is made from a soy protein that is a waste product of the tofu manufacturing process. Yummy. It is a durable fiber with a soft hand, great drape, good colorfastness, excellent absorbency, good comfort, and good thermal retention. We had some SoySilk® in lab too. I liked it a lot. If it isn't too expensive I want to use it to make a shirt.
Silk Latte® is a type of azlon made from milk protein. It is similar to SoySilk® but slightly less durable.
Showing posts with label textiles study guide. Show all posts
Showing posts with label textiles study guide. Show all posts
Tuesday, March 2, 2010
Monday, March 1, 2010
Textiles review: natural protein fibers
This is part three of my textiles review, in which we go over the natural protein fibers.
Natural protein fibers come from animals. Wools are the hair and fur of animals, and silk is secreted by silkworms. The protein in wools is keratin, and the protein in silk is fibroin. While the word “wool” technically refers to any hair fiber from any animal, it is commonly understood to refer only to sheep hair. Specialty wools (fibers from other animals) are usually referred to by the animal’s name, and they cost more than sheep wool.
All natural protein fibers share certain properties because of their common chemical composition. These properties are:
Resiliency: Protein fibers are resilient. They resist wrinkling, and wrinkles may disappear between uses. Wool is more resilient than silk.
Hygroscopic: Protein fibers are highly absorbent. They shed water slowly, so they retain their insulation properties and remain dry to the touch while wet.
Weaker when wet: Protein fibers have lower tenacity when wet. Silk loses about 15% strength when wet, and wool loses about 40%.
Specific gravity: Protein fibers have a lower specific gravity than cellulosic fibers.
Harmed by alkalis, oxidizing agents, and dry heat: Detergents, bleaches, and sweat damage the fibers. Steam should be use when ironing. Most protein fiber garments require dry-cleaning.
Flame resistant: Protein fibers do not ignite easily and will self-extinguish. They emit a burnt-hair smell and leave behind a black, powdery ash.
Wool
This section is about sheep wool. Specialty wools will be covered later.
Wool is a staple fiber from sheep’s hair. Wool is produced primarily in Australia, New Zealand, China, and Eastern Europe. The U.S. produces less than 1% of the world’s wool.
Wool production
Sheep are sheared once per year, usually in the spring. A newly removed fleece (raw or grease wool) contains 30% to 70% by weight of impurities such as dirt, grease, and sweat. The fleece is cleaned to produce scoured wool. The fleece is graded to evaluate it for fineness and length, then sorted to separate the sections of different qualities. Wool fibers are laid parallel to one another and twisted together to make yarns. Felt is made by pressing wool fibers together without twisting them into yarns.
Physical structure of wool
Length: Long, fine wool fibers, with an average length of 2½ inches, are used for worsted yarns. Short, coarse fibers, with an average length of 1½ inches, are used for woolen yarns.
Longitudinal view: Wool is a naturally crimped fiber. The fiber twists and bends back and forth around its axis giving it spring like qualities. The crimp accounts for wool’s excellent resiliency, flexibility, elongation, and elastic recovery.
Cross-sectional view: Wool fibers have diameters ranging from 10 to 50 micrometers. The fibers are round. The cuticle, the outer layer of the fiber, contains a dense layer of scales. These scales make the fibers water repellent, and allow felting. The cortex is the main part of the fiber. The cells on either side of the cortex react differently to moisture and temperature, giving wool its crimp. The center of the wool fiber is the medulla, a microscopic honeycomb-like structure containing air spaces. These air spaces add to wool’s thermal retention. Most worsted fibers do not contain medullas.
Properties of wool:
Aesthetics: Wool varies in color from white to dark brown. It accepts and holds dyes well. Woolen wool has a matte appearance; worsted wool may be more lustrous. Texture and drape are determined by yarn and fabric structure and by finish.
Durability: Wool fabrics are durable. Wool has a low tenacity (1.5 g/d), but its excellent elongation and elastic recovery allow it to resist damage. Wool’s wet tenacity is 1.0 g/d.
Comfort: Wool is highly hygroscopic – it is highly absorbent and it releases moisture slowly. Wool absorbs small droplets of moisture such as sweat while repelling larger droplets such as rain. Wool is a poor conductor of heat which makes it an excellent insulator. Wool continues to provide insulation while wet. Wool may induce an allergic reaction in some people.
Appearance retention: Wool is a highly resilient and elastic fiber. It resists wrinkling, and recovers its shape. If properly cared for wool has good dimensional stability, but if improperly washed it will shrink, felt, and tear. Wool should be dry-cleaned. Wool does not soil or stain readily, and with proper cleaning techniques stains can be removed.
Care: I can’t say this enough: WOOL IS DRY-CLEAN ONLY! Wool is damaged by alkalis (most detergents) and chlorine bleach. Moths eat wool; store your wool carefully. Wool is slow to ignite and it self-extinguishes, but there is still no good reason for you to set your wool clothes on fire.
Specialty wools
Mohair comes from the Angora goat. It is a smooth, silky, fine fiber without crimp. Most fibers do not have a medulla. Mohair is highly resilient.
Cashmere is from the Cashmere goat. The fibers have very fine scales and no medullas. It is used to make fabrics with a warm, soft, buttery hand, lustrous appearance, and excellent draping characteristics. It is expensive.
Llama and Alpaca wools come from South American cousins of the camel. Alpaca fiber’s soft hand, good luster, and excellent draping characteristics make it good for apparel. Llama fiber is coarser than alpaca fiber. It is often used for coats and suitings.
Camel’s hair is from the two-humped beasties (Bactrian camels). The hair is shed naturally; camels do not need to be shorn. The fiber provides great insulation without weight. It is usually used in coats, scarves, and suits. It is a tan fiber that is usually used undyed.
Angora is from the Angora rabbit. It is a long, fine, fluffy, soft, and slippery fiber. The fiber does not dye well. It is difficult to spin into yarns because it is so sleek, so it is often blended with other wools. Lambs are cute, but the Angora rabbit is the most adorable wool critter.
Silk
Silk is the only natural filament fiber. Silk was first used as a fiber in Chine more than 4,000 years ago. It is excreted by the silkworm to spin its cocoon in an attempt to metamorphose into a moth.
Silk production
Sericulture is the production of cultivated silk. Silk moths lay eggs on specially prepared paper. After the larvae hatch they are fed mulberry leaves. After roughly five weeks the caterpillars begin to spin their cocoons. Cocoons are made from a single strand of silk, approximately one mile long. The strands of silk are coated with a gum, called sericin. After the cocoon is finished, the pupa is killed with heat. The cocoons are unwound to produce fibers, the sericin is removed, and the fibers are wound together to produce yarn.
Wild silk is produced by collecting empty chrysalises from wild silkworms. The adult moth tears through the fiber as it exits the cocoon, so wild silk is a staple fiber. The sericin is not removed from wild silks.
Physical structure of silk
Silk is a smooth, thin fiber. The diameter of silk fiber is approximately 11 micrometers. It is a solid fiber with a triangular cross shape. Slight striations may be present along the length of the fiber. Wild silk tends to be coarser than cultivated silk.
Properties of silk
Aesthetics: Silk is a luxury fiber. It has a soft luster with an occasional sparkle. It wrinkles more easily than wool, but it is more resilient than cotton. Its color, hand, and drape vary. Wild silks have duller luster and more texture than cultivated silks.
Durability: Silk is one of the strongest natural fibers with a dry tenacity of 4.5 g/d. It loses up to 20% strength when wet. Silk has medium elasticity; at 2% elongation it returns to only 90% of its original length. Silk is damaged by sweat, body oils, chlorine bleach, sunlight, mineral acids, metallic salts (deodorants), and carpet beetles. It is resistant to hydrogen peroxide.
Comfort: Silk is a poor conductor of heat, so it can provide insulation. Light weight silk fabrics are comfortable in warm weather. It has good absorbency, and it is hygroscopic. Silk may develop a static charge. Silk has a soft, smooth, silky hand.
Appearance retention: Silk has moderate resistance to wrinkling. With its low elasticity, if it gets stretched it will stay stretched. Silk has moderate abrasion resistance, but with its typical uses it is rarely subjected to harsh abrasions. Staple silk may pill.
Care: Silk should by dry-cleaned. Silk may be pressed at moderate heat (300oF) with a damp press cloth. Silk is flame retardant and self extinguishing, but you should still keep it away from open flames.
Types of silk
Tussah is the most common type of wild silk
Noil silk (waste silk) is a staple fiber made from the broken pieces and cocoon remnants of cultivated silk.
Duppioni silk is made if two silkworms spin their cocoons together. It is not possible to fully separate the fibers. The yarns have a thick-and-thin appearance. It is used to make shantung.
Spider silk is not currently commercially produced, but several researchers are attempting to develop cost effective ways to produce it. The protein in spider silk is spidroin. Spider silk has excellent tenacity and elasticity. Efforts have been made to collect the silk directly from spiders and to genetically enhance silkworms and goats to produce it. A piece of spider silk fabric is currently on display at the American Museum of Natural History in New York.
Natural protein fibers come from animals. Wools are the hair and fur of animals, and silk is secreted by silkworms. The protein in wools is keratin, and the protein in silk is fibroin. While the word “wool” technically refers to any hair fiber from any animal, it is commonly understood to refer only to sheep hair. Specialty wools (fibers from other animals) are usually referred to by the animal’s name, and they cost more than sheep wool.
All natural protein fibers share certain properties because of their common chemical composition. These properties are:
Resiliency: Protein fibers are resilient. They resist wrinkling, and wrinkles may disappear between uses. Wool is more resilient than silk.
Hygroscopic: Protein fibers are highly absorbent. They shed water slowly, so they retain their insulation properties and remain dry to the touch while wet.
Weaker when wet: Protein fibers have lower tenacity when wet. Silk loses about 15% strength when wet, and wool loses about 40%.
Specific gravity: Protein fibers have a lower specific gravity than cellulosic fibers.
Harmed by alkalis, oxidizing agents, and dry heat: Detergents, bleaches, and sweat damage the fibers. Steam should be use when ironing. Most protein fiber garments require dry-cleaning.
Flame resistant: Protein fibers do not ignite easily and will self-extinguish. They emit a burnt-hair smell and leave behind a black, powdery ash.
Wool
This section is about sheep wool. Specialty wools will be covered later.
Wool is a staple fiber from sheep’s hair. Wool is produced primarily in Australia, New Zealand, China, and Eastern Europe. The U.S. produces less than 1% of the world’s wool.
Wool production
Sheep are sheared once per year, usually in the spring. A newly removed fleece (raw or grease wool) contains 30% to 70% by weight of impurities such as dirt, grease, and sweat. The fleece is cleaned to produce scoured wool. The fleece is graded to evaluate it for fineness and length, then sorted to separate the sections of different qualities. Wool fibers are laid parallel to one another and twisted together to make yarns. Felt is made by pressing wool fibers together without twisting them into yarns.
Physical structure of wool
Length: Long, fine wool fibers, with an average length of 2½ inches, are used for worsted yarns. Short, coarse fibers, with an average length of 1½ inches, are used for woolen yarns.
Longitudinal view: Wool is a naturally crimped fiber. The fiber twists and bends back and forth around its axis giving it spring like qualities. The crimp accounts for wool’s excellent resiliency, flexibility, elongation, and elastic recovery.
Cross-sectional view: Wool fibers have diameters ranging from 10 to 50 micrometers. The fibers are round. The cuticle, the outer layer of the fiber, contains a dense layer of scales. These scales make the fibers water repellent, and allow felting. The cortex is the main part of the fiber. The cells on either side of the cortex react differently to moisture and temperature, giving wool its crimp. The center of the wool fiber is the medulla, a microscopic honeycomb-like structure containing air spaces. These air spaces add to wool’s thermal retention. Most worsted fibers do not contain medullas.
Properties of wool:
Aesthetics: Wool varies in color from white to dark brown. It accepts and holds dyes well. Woolen wool has a matte appearance; worsted wool may be more lustrous. Texture and drape are determined by yarn and fabric structure and by finish.
Durability: Wool fabrics are durable. Wool has a low tenacity (1.5 g/d), but its excellent elongation and elastic recovery allow it to resist damage. Wool’s wet tenacity is 1.0 g/d.
Comfort: Wool is highly hygroscopic – it is highly absorbent and it releases moisture slowly. Wool absorbs small droplets of moisture such as sweat while repelling larger droplets such as rain. Wool is a poor conductor of heat which makes it an excellent insulator. Wool continues to provide insulation while wet. Wool may induce an allergic reaction in some people.
Appearance retention: Wool is a highly resilient and elastic fiber. It resists wrinkling, and recovers its shape. If properly cared for wool has good dimensional stability, but if improperly washed it will shrink, felt, and tear. Wool should be dry-cleaned. Wool does not soil or stain readily, and with proper cleaning techniques stains can be removed.
Care: I can’t say this enough: WOOL IS DRY-CLEAN ONLY! Wool is damaged by alkalis (most detergents) and chlorine bleach. Moths eat wool; store your wool carefully. Wool is slow to ignite and it self-extinguishes, but there is still no good reason for you to set your wool clothes on fire.
Specialty wools
Mohair comes from the Angora goat. It is a smooth, silky, fine fiber without crimp. Most fibers do not have a medulla. Mohair is highly resilient.
Cashmere is from the Cashmere goat. The fibers have very fine scales and no medullas. It is used to make fabrics with a warm, soft, buttery hand, lustrous appearance, and excellent draping characteristics. It is expensive.
Llama and Alpaca wools come from South American cousins of the camel. Alpaca fiber’s soft hand, good luster, and excellent draping characteristics make it good for apparel. Llama fiber is coarser than alpaca fiber. It is often used for coats and suitings.
Camel’s hair is from the two-humped beasties (Bactrian camels). The hair is shed naturally; camels do not need to be shorn. The fiber provides great insulation without weight. It is usually used in coats, scarves, and suits. It is a tan fiber that is usually used undyed.
Angora is from the Angora rabbit. It is a long, fine, fluffy, soft, and slippery fiber. The fiber does not dye well. It is difficult to spin into yarns because it is so sleek, so it is often blended with other wools. Lambs are cute, but the Angora rabbit is the most adorable wool critter.
Silk
Silk is the only natural filament fiber. Silk was first used as a fiber in Chine more than 4,000 years ago. It is excreted by the silkworm to spin its cocoon in an attempt to metamorphose into a moth.
Silk production
Sericulture is the production of cultivated silk. Silk moths lay eggs on specially prepared paper. After the larvae hatch they are fed mulberry leaves. After roughly five weeks the caterpillars begin to spin their cocoons. Cocoons are made from a single strand of silk, approximately one mile long. The strands of silk are coated with a gum, called sericin. After the cocoon is finished, the pupa is killed with heat. The cocoons are unwound to produce fibers, the sericin is removed, and the fibers are wound together to produce yarn.
Wild silk is produced by collecting empty chrysalises from wild silkworms. The adult moth tears through the fiber as it exits the cocoon, so wild silk is a staple fiber. The sericin is not removed from wild silks.
Physical structure of silk
Silk is a smooth, thin fiber. The diameter of silk fiber is approximately 11 micrometers. It is a solid fiber with a triangular cross shape. Slight striations may be present along the length of the fiber. Wild silk tends to be coarser than cultivated silk.
Properties of silk
Aesthetics: Silk is a luxury fiber. It has a soft luster with an occasional sparkle. It wrinkles more easily than wool, but it is more resilient than cotton. Its color, hand, and drape vary. Wild silks have duller luster and more texture than cultivated silks.
Durability: Silk is one of the strongest natural fibers with a dry tenacity of 4.5 g/d. It loses up to 20% strength when wet. Silk has medium elasticity; at 2% elongation it returns to only 90% of its original length. Silk is damaged by sweat, body oils, chlorine bleach, sunlight, mineral acids, metallic salts (deodorants), and carpet beetles. It is resistant to hydrogen peroxide.
Comfort: Silk is a poor conductor of heat, so it can provide insulation. Light weight silk fabrics are comfortable in warm weather. It has good absorbency, and it is hygroscopic. Silk may develop a static charge. Silk has a soft, smooth, silky hand.
Appearance retention: Silk has moderate resistance to wrinkling. With its low elasticity, if it gets stretched it will stay stretched. Silk has moderate abrasion resistance, but with its typical uses it is rarely subjected to harsh abrasions. Staple silk may pill.
Care: Silk should by dry-cleaned. Silk may be pressed at moderate heat (300oF) with a damp press cloth. Silk is flame retardant and self extinguishing, but you should still keep it away from open flames.
Types of silk
Tussah is the most common type of wild silk
Noil silk (waste silk) is a staple fiber made from the broken pieces and cocoon remnants of cultivated silk.
Duppioni silk is made if two silkworms spin their cocoons together. It is not possible to fully separate the fibers. The yarns have a thick-and-thin appearance. It is used to make shantung.
Spider silk is not currently commercially produced, but several researchers are attempting to develop cost effective ways to produce it. The protein in spider silk is spidroin. Spider silk has excellent tenacity and elasticity. Efforts have been made to collect the silk directly from spiders and to genetically enhance silkworms and goats to produce it. A piece of spider silk fabric is currently on display at the American Museum of Natural History in New York.
Sunday, February 28, 2010
Textiles review: natural cellulosic fibers
This is part two of my textiles review in preparation for my upcoming test.
Plants contain cellulosic fibrous bundles in their roots, stems, leaves, and seed casings. These fibers may be easily removed from some plants to be used as textile fibers. Fibers are classified according to the part of the plant from which they are removed. Seed fibers grow in the seedpod of plants, bast fibers are from a plant’s roots or stems, and leaf fibers are obtained from leaves.
Examples of seed fibers are cotton, kapok, coir, and milkweed.
Examples of bast fibers are flax, ramie, hemp, and jute.
Examples of leaf fibers are piña, abaca, sisal, and henequen.
While there are great differences between various natural cellulosic fibers, there are some properties they all share because of their similar chemical make-up. Properties common to natural cellulosic fibers are:
Good absorbency – cellulose can take up a lot of moisture. Natural cellulosic fibers are good for summer wear, towels, diapers, and active sportswear.
Good conductor of heat (poor thermal retention) – Natural cellulosic fibers are bad insulators. Apparel made from these fabrics does not trap heat. It is a cool fabric suitable for use in warm environments.
Able to withstand high temperature – Natural cellulosic fibers can be washed and ironed at high temperatures. They may be boiled or autoclaved for sterilization.
Low resiliency – Fabrics wrinkle badly.
Poor loft – Fibers can form dense, high count yarns and fabrics. They may be used to make wind resistant fabrics.
Good electrical conductor – Fabrics do not build up a static charge.
Heavy fibers – Fiber density is approximately 1.5 g/cc. Natural cellulosic fibers are heavier than natural protein fibers and most manufactured fibers.
Damaged by mineral acids – Try to avoid acid stains. If you can’t avoid them, clean them quickly.
Resistant to alkalis – Fabrics may be washed with regular detergents.
Damaged by mildew, crickets, and silverfish – Store items in dry conditions.
Resistant to moths – Moths will not eat cellulosic fibers, but you still do not want moths living in your closet.
Inflammable – Fibers ignite quickly and continue to burn after being removed from the ignition source. Burnt fibers smell like burnt wood and leave behind a white or light grey powdery ash.
Poor to moderate sunlight resistance – The fibers are suitable for outdoor apparel, but window treatments should be lined to prevent too much exposure to sunlight.
Cotton
Cotton is the most commonly used natural cellulosic fiber. Cotton fibers grow from the seeds in the boll (seedpod). Each boll contains seven or eight seeds, and each seed may have up to 20,000 fibers growing from it.
Cotton production
Ripe bolls are picked by machines. They are sent to a gin where the seeds are separated from the fibers. The fibers, called lint, are packed into bales and sent to spinning mills. Each bale weighs 480 pounds. The spinning mills make yarns.
Physical structure of cotton:
Color: Most cotton fibers are a creamy white or light tan, but some naturally colored cottons are available. Colored cottons produce less per acre than white cotton, but they sell for about twice as much. Brown, red, beige, and green are available. Unlike most dyed fabrics, colored cottons become darker with age and care. Cotton fibers take up dyes well.
Length: Cotton is a staple fiber. The fibers range in length from ½ to 2½ inches depending on the genetic variety of the plant. Long staple cottons, which are greater than 1 5/16 inch are finer and make stronger, higher quality yarns. They cost a lot more too. Sea Island, Egyptian, Pima, and Supima are types of long staple cottons. Upland cottons, the most commonly grown cottons in the U.S., are medium length cottons (7/8 to 1¼ inch). Short-stable cottons (less than ¾ inch) are produced primarily in Asia.
Cross-sectional view: Cotton fibers are 16 to 20 micrometers in diameter. The fiber has a thin primary cell wall surrounding a thicker secondary cell wall. The center of the fiber is the lumen, the central canal through which nutrients travel as the fiber grows. Immature fibers are U shaped, and mature fibers are kidney shaped.
Longitudinal view: Cotton fibers have a ribbon-like twist called convolutions. The convolutions allow the fibers to cling together which makes yarn spinning easy.
Properties of cotton:
Aesthetics: Cotton has a matte appearance and low luster. Cotton can be made slightly lustrous through mercerization, i.e. treating it with NaOH which causes the fibers to swell. The drape and texture is affected by the yarn size, fabric structure, and finish. Cotton wrinkles easily.
Durability: Cotton is a medium-strength fiber, with a dry breaking tenacity of 3.5 to 4.0 grams per denier. It is 30% stronger when wet. Cotton has good abrasion resistance, low elongation (3%), and moderate elasticity.
Comfort: Cotton’s good heat conductivity, good electrical conductivity, high absorbency, and soft hand make it a very comfortable apparel fabric, particularly for use in warm environments.
Appearance retention: Cotton has moderate appearance retention. Its low resiliency allows it to wrinkle easily, but wrinkles may be pressed out. Cotton will shrink unless it is given a durable-press or wrinkle-resistant finish. Cotton has moderate elastic recovery; it recovers 75% from 2% to 5% stretch. Stretched cotton garments stay stretched.
Care: Cotton soils and stains easily. Cotton withstands high heat, it is stronger when wet, and it is resistant to alkalis, so it may be machine washed with hot water and normal detergent. Cotton may be ironed at high temperatures. Cotton should be stored in dry conditions to prevent damage from mildew.
Other seed fibers
Coir is from the fibrous mass between the outer shell and husk of coconuts. It is a stiff fiber. It is usually used to make highly durable indoor and outdoor mats, rugs, and tiles.
Kapok fiber is from the seed of the Java or Indian kapok tree. The fiber is soft, lightweight, and hollow. It breaks down easily and it is difficult to spin into yarns. It is used as fiberfill and as the stuffing for pillows. It used to be used as a stuffing for lifejackets and the mattresses on cruise ships because it is very buoyant.
Milkweed has properties similar to those of kapok.
Flax
Flax is one of the oldest textile fibers, but its use has declined since the invention of power spinning for cotton. Flax fabric is linen, although the word linen is now often used to refer to table, bed, and bath fabrics made from other materials. Flax is a bast fiber.
Production of flax
Flax fibers are from the stems and roots of the flax plant. The plant is cut or pulled out of the ground to keep the fibers as long as possible. The fibers are found just under the bark or outer covering of the plant. They are sealed together by pectins, gums, and waxes. There are four steps to obtain fibers from the plant:
Rippling – the plant is pulled through a machine to remove the seeds.
Retting – bacteria break down the pectin that binds the fibers together.
Scutching – the stalks are passed through rollers to crush and remove the outer covering so the fibers may be removed.
Hackling – the fibers are combed to separate them into individual strands.
Physical structure of flax
Length: Flax is a staple fiber. Flax fibers range in length from 2 to 36 inches. Short fibers are called tow; long fibers are called line.
Cross-sectional view: Flax fibers are 12 to 16 micrometers in diameter. They have a polygonal shape. There is a small central canal similar to cotton’s lumen.
Longitudinal view: Flax fibers are straight. There are crosswise markings, called nodes, along the length of the fiber.
Properties of flax
Aesthetics: Flax has a high luster that can be further increased with finishes. Flax has a stiffer drape and harsher hand than cotton. Flax takes up dyes well.
Durability: Flax is strong for a natural fiber. Its dry tenacity is 3.5 to 5.0 g/d, and its wet tenacity is 6.0 g/d. Flax has very low elongation (7%) and poor elasticity (65% recovery at 2% elongation). Flax has good flat abrasion resistance, but poor flex abrasion resistance. Repeatedly folding a piece of linen in the same place will cause the fibers to break.
Comfort: Flax is a good fabric for summer apparel. Its high absorbency (better than cotton), wicking properties, and poor thermal retention make it very comfortable in warm weather. It will not build up a static charge.
Appearance retention: Flax has poor appearance retention. It wrinkles very easily and does not recover from being stretched.
Care: Flax withstands high heat, it is stronger when wet, and it is resistant to alkalis, so it may be machine washed with hot water and normal detergent. Flax may be ironed at high temperatures, and it will require pressing often. Flax should be stored in dry conditions to prevent damage from mildew.
Other bast fibers
Ramie: Ramie fibers are 4 to 6 inches long. The fibers are whiter and softer than flax. Ramie does not retain dyes well unless it is dry-cleaned. Ramie is strong for a natural fiber, but it lacks resiliency, elasticity, and elongation potential. It is resistant to mildew, insects, and shrinkage. It is used for apparel, window treatments, ropes, paper, and table and bed linens.
Hemp: Hemp is similar to flax. The fibers range in length from 3 to 15 feet. Hemp production is illegal in the U.S. Hemp has a low environmental impact; it does not require pesticides. It produces 250% more fiber than cotton and 600% more fiber than flax on the same amount of land. Hemp plants can be used to extract zinc and mercury pollutants from soil. Hemp is used for ropes, apparel, and paper. Potheads are willing to pay inflated prices for hemp apparel because it is related to the marijuana plant.
Jute: Jute is one of the cheapest textile fibers, and one of the weakest cellulosic fibers. Jute has poor elasticity, elongation, sunlight resistance, mildew resistance, and colorfastness. It is used to produce sugar and coffee bagging, carpet backing, rope, and wall coverings. Burlap is made from jute.
Leaf fibers
Piña fibers are from the leaves of the pineapple plant. It is used to make lightweight, sheer, stiff fabrics for apparel, bags, and table linens. It is also used to make mats.
Abaca is from a member of the banana tree family. The fibers are coarse and very long (up to 15 feet). It is a strong, durable, and flexible fiber used for ropes, floor mats, table linens, apparel, and wicker furniture.
Sisal and henequen are similar plants. The fibers can be used to make strong ropes, but they are damaged to salt water so they are not suitable for maritime ropes. The fibers are used for upholstery, carpets, and wall coverings.
Plants contain cellulosic fibrous bundles in their roots, stems, leaves, and seed casings. These fibers may be easily removed from some plants to be used as textile fibers. Fibers are classified according to the part of the plant from which they are removed. Seed fibers grow in the seedpod of plants, bast fibers are from a plant’s roots or stems, and leaf fibers are obtained from leaves.
Examples of seed fibers are cotton, kapok, coir, and milkweed.
Examples of bast fibers are flax, ramie, hemp, and jute.
Examples of leaf fibers are piña, abaca, sisal, and henequen.
While there are great differences between various natural cellulosic fibers, there are some properties they all share because of their similar chemical make-up. Properties common to natural cellulosic fibers are:
Good absorbency – cellulose can take up a lot of moisture. Natural cellulosic fibers are good for summer wear, towels, diapers, and active sportswear.
Good conductor of heat (poor thermal retention) – Natural cellulosic fibers are bad insulators. Apparel made from these fabrics does not trap heat. It is a cool fabric suitable for use in warm environments.
Able to withstand high temperature – Natural cellulosic fibers can be washed and ironed at high temperatures. They may be boiled or autoclaved for sterilization.
Low resiliency – Fabrics wrinkle badly.
Poor loft – Fibers can form dense, high count yarns and fabrics. They may be used to make wind resistant fabrics.
Good electrical conductor – Fabrics do not build up a static charge.
Heavy fibers – Fiber density is approximately 1.5 g/cc. Natural cellulosic fibers are heavier than natural protein fibers and most manufactured fibers.
Damaged by mineral acids – Try to avoid acid stains. If you can’t avoid them, clean them quickly.
Resistant to alkalis – Fabrics may be washed with regular detergents.
Damaged by mildew, crickets, and silverfish – Store items in dry conditions.
Resistant to moths – Moths will not eat cellulosic fibers, but you still do not want moths living in your closet.
Inflammable – Fibers ignite quickly and continue to burn after being removed from the ignition source. Burnt fibers smell like burnt wood and leave behind a white or light grey powdery ash.
Poor to moderate sunlight resistance – The fibers are suitable for outdoor apparel, but window treatments should be lined to prevent too much exposure to sunlight.
Cotton
Cotton is the most commonly used natural cellulosic fiber. Cotton fibers grow from the seeds in the boll (seedpod). Each boll contains seven or eight seeds, and each seed may have up to 20,000 fibers growing from it.
Cotton production
Ripe bolls are picked by machines. They are sent to a gin where the seeds are separated from the fibers. The fibers, called lint, are packed into bales and sent to spinning mills. Each bale weighs 480 pounds. The spinning mills make yarns.
Physical structure of cotton:
Color: Most cotton fibers are a creamy white or light tan, but some naturally colored cottons are available. Colored cottons produce less per acre than white cotton, but they sell for about twice as much. Brown, red, beige, and green are available. Unlike most dyed fabrics, colored cottons become darker with age and care. Cotton fibers take up dyes well.
Length: Cotton is a staple fiber. The fibers range in length from ½ to 2½ inches depending on the genetic variety of the plant. Long staple cottons, which are greater than 1 5/16 inch are finer and make stronger, higher quality yarns. They cost a lot more too. Sea Island, Egyptian, Pima, and Supima are types of long staple cottons. Upland cottons, the most commonly grown cottons in the U.S., are medium length cottons (7/8 to 1¼ inch). Short-stable cottons (less than ¾ inch) are produced primarily in Asia.
Cross-sectional view: Cotton fibers are 16 to 20 micrometers in diameter. The fiber has a thin primary cell wall surrounding a thicker secondary cell wall. The center of the fiber is the lumen, the central canal through which nutrients travel as the fiber grows. Immature fibers are U shaped, and mature fibers are kidney shaped.
Longitudinal view: Cotton fibers have a ribbon-like twist called convolutions. The convolutions allow the fibers to cling together which makes yarn spinning easy.
Properties of cotton:
Aesthetics: Cotton has a matte appearance and low luster. Cotton can be made slightly lustrous through mercerization, i.e. treating it with NaOH which causes the fibers to swell. The drape and texture is affected by the yarn size, fabric structure, and finish. Cotton wrinkles easily.
Durability: Cotton is a medium-strength fiber, with a dry breaking tenacity of 3.5 to 4.0 grams per denier. It is 30% stronger when wet. Cotton has good abrasion resistance, low elongation (3%), and moderate elasticity.
Comfort: Cotton’s good heat conductivity, good electrical conductivity, high absorbency, and soft hand make it a very comfortable apparel fabric, particularly for use in warm environments.
Appearance retention: Cotton has moderate appearance retention. Its low resiliency allows it to wrinkle easily, but wrinkles may be pressed out. Cotton will shrink unless it is given a durable-press or wrinkle-resistant finish. Cotton has moderate elastic recovery; it recovers 75% from 2% to 5% stretch. Stretched cotton garments stay stretched.
Care: Cotton soils and stains easily. Cotton withstands high heat, it is stronger when wet, and it is resistant to alkalis, so it may be machine washed with hot water and normal detergent. Cotton may be ironed at high temperatures. Cotton should be stored in dry conditions to prevent damage from mildew.
Other seed fibers
Coir is from the fibrous mass between the outer shell and husk of coconuts. It is a stiff fiber. It is usually used to make highly durable indoor and outdoor mats, rugs, and tiles.
Kapok fiber is from the seed of the Java or Indian kapok tree. The fiber is soft, lightweight, and hollow. It breaks down easily and it is difficult to spin into yarns. It is used as fiberfill and as the stuffing for pillows. It used to be used as a stuffing for lifejackets and the mattresses on cruise ships because it is very buoyant.
Milkweed has properties similar to those of kapok.
Flax
Flax is one of the oldest textile fibers, but its use has declined since the invention of power spinning for cotton. Flax fabric is linen, although the word linen is now often used to refer to table, bed, and bath fabrics made from other materials. Flax is a bast fiber.
Production of flax
Flax fibers are from the stems and roots of the flax plant. The plant is cut or pulled out of the ground to keep the fibers as long as possible. The fibers are found just under the bark or outer covering of the plant. They are sealed together by pectins, gums, and waxes. There are four steps to obtain fibers from the plant:
Rippling – the plant is pulled through a machine to remove the seeds.
Retting – bacteria break down the pectin that binds the fibers together.
Scutching – the stalks are passed through rollers to crush and remove the outer covering so the fibers may be removed.
Hackling – the fibers are combed to separate them into individual strands.
Physical structure of flax
Length: Flax is a staple fiber. Flax fibers range in length from 2 to 36 inches. Short fibers are called tow; long fibers are called line.
Cross-sectional view: Flax fibers are 12 to 16 micrometers in diameter. They have a polygonal shape. There is a small central canal similar to cotton’s lumen.
Longitudinal view: Flax fibers are straight. There are crosswise markings, called nodes, along the length of the fiber.
Properties of flax
Aesthetics: Flax has a high luster that can be further increased with finishes. Flax has a stiffer drape and harsher hand than cotton. Flax takes up dyes well.
Durability: Flax is strong for a natural fiber. Its dry tenacity is 3.5 to 5.0 g/d, and its wet tenacity is 6.0 g/d. Flax has very low elongation (7%) and poor elasticity (65% recovery at 2% elongation). Flax has good flat abrasion resistance, but poor flex abrasion resistance. Repeatedly folding a piece of linen in the same place will cause the fibers to break.
Comfort: Flax is a good fabric for summer apparel. Its high absorbency (better than cotton), wicking properties, and poor thermal retention make it very comfortable in warm weather. It will not build up a static charge.
Appearance retention: Flax has poor appearance retention. It wrinkles very easily and does not recover from being stretched.
Care: Flax withstands high heat, it is stronger when wet, and it is resistant to alkalis, so it may be machine washed with hot water and normal detergent. Flax may be ironed at high temperatures, and it will require pressing often. Flax should be stored in dry conditions to prevent damage from mildew.
Other bast fibers
Ramie: Ramie fibers are 4 to 6 inches long. The fibers are whiter and softer than flax. Ramie does not retain dyes well unless it is dry-cleaned. Ramie is strong for a natural fiber, but it lacks resiliency, elasticity, and elongation potential. It is resistant to mildew, insects, and shrinkage. It is used for apparel, window treatments, ropes, paper, and table and bed linens.
Hemp: Hemp is similar to flax. The fibers range in length from 3 to 15 feet. Hemp production is illegal in the U.S. Hemp has a low environmental impact; it does not require pesticides. It produces 250% more fiber than cotton and 600% more fiber than flax on the same amount of land. Hemp plants can be used to extract zinc and mercury pollutants from soil. Hemp is used for ropes, apparel, and paper. Potheads are willing to pay inflated prices for hemp apparel because it is related to the marijuana plant.
Jute: Jute is one of the cheapest textile fibers, and one of the weakest cellulosic fibers. Jute has poor elasticity, elongation, sunlight resistance, mildew resistance, and colorfastness. It is used to produce sugar and coffee bagging, carpet backing, rope, and wall coverings. Burlap is made from jute.
Leaf fibers
Piña fibers are from the leaves of the pineapple plant. It is used to make lightweight, sheer, stiff fabrics for apparel, bags, and table linens. It is also used to make mats.
Abaca is from a member of the banana tree family. The fibers are coarse and very long (up to 15 feet). It is a strong, durable, and flexible fiber used for ropes, floor mats, table linens, apparel, and wicker furniture.
Sisal and henequen are similar plants. The fibers can be used to make strong ropes, but they are damaged to salt water so they are not suitable for maritime ropes. The fibers are used for upholstery, carpets, and wall coverings.
Saturday, February 27, 2010
Textiles review: fiber properties & serviceability concepts
The first test of the semester in my textiles class is rapidly approaching. I have attended every lecture and lab, done all my homework, taken meticulous notes, and kept up with all the readings, and still I am worried. There is a lot I need to know. The professor gave us a study guide for the test, but she could have conveyed the same information by simply saying, “Memorize chapters one through seven.” I decided to summarize the important concepts in a blog entry. I expect doing so will help me retain this information, and perhaps some of you will find it useful and interesting too.
Chapter 1 – Introduction to textiles
Fiber – any substance with a high length to width ratio and suitable characteristics for being processed into a fabric. Fibers are the smallest components of a fabric.
Yarn – an assemblage of fibers twisted or laid together to make a continuous strand.
Fabric – a flexible planar substance constructed from solutions, fibers, yarns, or fabrics, in any combination.
Gray (grey, greige) goods – an unfinished fabric.
Finish – any process used to add color and enhance performance of gray goods.
Textile (textbook definition) – this term originally meant woven fabrics, but it is now used to refer to fibers and anything made out of fibers.
Textile (lecture definition) – fiber + yarn + structure + finish = textile. Gray goods are unfinished. Felt is made without yarn.
Chapter 2 – Serviceability concepts
Serviceability is a measure of a textile product’s ability to meet the specific needs of a customer. There are eight serviceability concepts used to describe a textile’s performance. These concepts do not describe a textile as good or bad, rather they allow a customer to understand how a textile will perform in specific situations. A textile that may be great in one environment may be terrible in another. For example, wool has excellent thermal retention, so a wool sweater that is comfortable in winter is uncomfortable in summer.
The eight serviceability concepts are aesthetics, durability, comfort, safety, appearance retention, care, environmental impact, and cost. The terms in italics after the definitions are fiber properties that relate to each concept. The properties will be defined in the next section.
Aesthetics – attractiveness/appearance of a textile. How it looks. Luster, drape, texture, hand, dyeability
Durability – the manner in which a textile withstands use. The length of time a product remains usable for the purpose for which it was intended. Abrasion resistance, flexibility, tenacity, elongation, sunlight resistance, moth resistance, mildew resistance
Comfort – the way a textile affects heat, air, and moisture transfer. How it feels to the body. Absorbency, heat conductivity, density, electrical conductivity, wicking
Safety – a textile’s ability to protect a body from harm. Tenacity, absorbency, heat conductivity, heat sensitivity, flammability
Appearance retention – how the product maintains its original appearance. Resiliency, dimensional stability, shrinkage resistance, elasticity, loft, sunlight resistance, pilling
Care – the treatment required to maintain a textile product’s original appearance and cleanliness. Moth resistance, heat resistance, mildew resistance, chemical reactivity, shrinkage resistance
Environmental impact – effects of production, use, care, and disposal of a textile product.
Cost – amount paid to acquire, use, maintain, and dispose of a textile product.
Chapter 3 – fibers and fiber properties
Fibers may be classed as natural or manufactured. Natural fibers grow in nature in recognizable fiber form. They come directly from plants (cellulosic fibers) or animals (protein fibers). Manufactured fibers are formed into fibers from chemical compounds. They do not exist in fiber form without human intervention. Manufactured fibers may be regenerated or synthetic. Regenerated fibers are produced from naturally occurring polymers that do not occur naturally as fibers. Regenerated fibers are made from cellulose (plant) or protein (plant or animal). Synthetic fibers are made from polymers that do not occur naturally. Most synthetic fibers are made from petrochemicals.
The properties of a fiber, yarn properties, fabric construction, and finish contribute to the properties of a fabric. The physical structure, chemical composition, and molecular arrangement of a fiber determine its serviceability properties.
Length is the measurement of the length of a fiber used to make yarns. Staple fibers are short fibers measured in inches or centimeters. Staple fibers range in length from less than one inch to approximately 18 inches. Except for silk, all natural fibers are available only as staple fibers. Filament fibers are long, continuous fibers measured in miles or kilometers. Silk and manufactured fibers may be either staple or filament.
A fiber’s diameter is measured in micrometers. Natural fibers are subject to growth irregularities that affect their diameter. The diameter of manufactured fibers is controlled during production.
Denier is the weight in grams of 9,000 meters of a fiber or yarn.
Fibers may be solid or hollow. Their surfaces may be smooth or textured. The cross sectional shape and surface contour of natural fibers is a result of how the fibers grow. The shape and surface contour of manufactured fibers is controlled during production.
Crimp is twists, curls, or coils along the length of a fiber. Crimp affects hand, cohesiveness, resiliency, stretch, bulk, heat retention, abrasion resistance, and absorbency. Crimp exists naturally in wool, and it can be added to manufactured fibers.
Properties:
Abrasion resistance is a fiber’s ability to resist damage from rubbing.
Absorbency (or moisture regain) is a fiber’s ability to take up moisture.
Chemical reactivity describes how a fiber responds to specific chemicals such as acids, alkalis, oxidizing agents, and solvents.
Density (or specific gravity) is the measure of the mass of a fiber per cubic centimeter. Specific gravity is the ratio of a fiber’s density to that of water (which has a density of 1g/cc at 4oC). Fibers with a specific gravity less than 1 float, while those whose specific gravity is greater than 1 sink.
Dimensional stability describes a fiber’s ability to retain a size and shape.
Drape describes how a fiber hangs over a three dimensional form.
Dyeability is a fiber’s ability to take up and retain dyes.
Elasticity is the ability of a fiber to return immediately to its original length.
Electrical conductivity is the ability of a fiber to transfer electrical current. Fibers with high electrical conductivity do not develop a static charge.
Elongation measures how much a fiber may be stretched without breaking.
Flammability is a fiber’s ability to burn. It describes how the fiber reacts to ignition sources, and at what temperature the fiber will ignite (if it is inflammable).
Hand describes how a fiber feels. Is it smooth, harsh, silky, dry, clammy, etc.?
Heat conductivity (or thermal retention) is the ability of a fiber to retain or transfer heat. It describes the insulation properties of a fiber. Fibers with low heat conductivity (high thermal retention) are good insulators.
Heat sensitivity describes how a fiber reacts to high heat. Does it shrink, soften, melt, discolor, or ignite if exposed to high heat, and at what temperature will it do so?
Loft is the ability of a fiber to spring back to its original thickness after being compressed.
Luster is the amount of light reflected from the surface of a fiber.
Mildew resistance describes a fiber’s ability to resist the growth of mildew, mold, and fungus.
Moth resistance is a fiber’s resistance to insect damage. It describes which insects (if any) will eat the fiber.
Pilling is the formation of balls of fiber (pills) on the surface of a fabric.
Resiliency is a fiber’s ability to return to its original shape after bending, twisting, and crushing. Fibers with high resiliency resist wrinkling.
Shrinkage resistance is a fiber’s ability to retain its original size through use and care.
Sunlight resistance is a fiber’s ability to withstand damage and discoloration from sunlight.
Tenacity is a fiber’s strength measured in grams per denier. The breaking tenacity of a fiber is the force required to break the fiber. Moisture affects a fiber’s tenacity, so the breaking tenacity is measured both dry and wet.
Texture is the nature of a fiber or fabric surface. It describes the way a fiber or fabric appears.
Chapter 1 – Introduction to textiles
Fiber – any substance with a high length to width ratio and suitable characteristics for being processed into a fabric. Fibers are the smallest components of a fabric.
Yarn – an assemblage of fibers twisted or laid together to make a continuous strand.
Fabric – a flexible planar substance constructed from solutions, fibers, yarns, or fabrics, in any combination.
Gray (grey, greige) goods – an unfinished fabric.
Finish – any process used to add color and enhance performance of gray goods.
Textile (textbook definition) – this term originally meant woven fabrics, but it is now used to refer to fibers and anything made out of fibers.
Textile (lecture definition) – fiber + yarn + structure + finish = textile. Gray goods are unfinished. Felt is made without yarn.
Chapter 2 – Serviceability concepts
Serviceability is a measure of a textile product’s ability to meet the specific needs of a customer. There are eight serviceability concepts used to describe a textile’s performance. These concepts do not describe a textile as good or bad, rather they allow a customer to understand how a textile will perform in specific situations. A textile that may be great in one environment may be terrible in another. For example, wool has excellent thermal retention, so a wool sweater that is comfortable in winter is uncomfortable in summer.
The eight serviceability concepts are aesthetics, durability, comfort, safety, appearance retention, care, environmental impact, and cost. The terms in italics after the definitions are fiber properties that relate to each concept. The properties will be defined in the next section.
Aesthetics – attractiveness/appearance of a textile. How it looks. Luster, drape, texture, hand, dyeability
Durability – the manner in which a textile withstands use. The length of time a product remains usable for the purpose for which it was intended. Abrasion resistance, flexibility, tenacity, elongation, sunlight resistance, moth resistance, mildew resistance
Comfort – the way a textile affects heat, air, and moisture transfer. How it feels to the body. Absorbency, heat conductivity, density, electrical conductivity, wicking
Safety – a textile’s ability to protect a body from harm. Tenacity, absorbency, heat conductivity, heat sensitivity, flammability
Appearance retention – how the product maintains its original appearance. Resiliency, dimensional stability, shrinkage resistance, elasticity, loft, sunlight resistance, pilling
Care – the treatment required to maintain a textile product’s original appearance and cleanliness. Moth resistance, heat resistance, mildew resistance, chemical reactivity, shrinkage resistance
Environmental impact – effects of production, use, care, and disposal of a textile product.
Cost – amount paid to acquire, use, maintain, and dispose of a textile product.
Chapter 3 – fibers and fiber properties
Fibers may be classed as natural or manufactured. Natural fibers grow in nature in recognizable fiber form. They come directly from plants (cellulosic fibers) or animals (protein fibers). Manufactured fibers are formed into fibers from chemical compounds. They do not exist in fiber form without human intervention. Manufactured fibers may be regenerated or synthetic. Regenerated fibers are produced from naturally occurring polymers that do not occur naturally as fibers. Regenerated fibers are made from cellulose (plant) or protein (plant or animal). Synthetic fibers are made from polymers that do not occur naturally. Most synthetic fibers are made from petrochemicals.
The properties of a fiber, yarn properties, fabric construction, and finish contribute to the properties of a fabric. The physical structure, chemical composition, and molecular arrangement of a fiber determine its serviceability properties.
Length is the measurement of the length of a fiber used to make yarns. Staple fibers are short fibers measured in inches or centimeters. Staple fibers range in length from less than one inch to approximately 18 inches. Except for silk, all natural fibers are available only as staple fibers. Filament fibers are long, continuous fibers measured in miles or kilometers. Silk and manufactured fibers may be either staple or filament.
A fiber’s diameter is measured in micrometers. Natural fibers are subject to growth irregularities that affect their diameter. The diameter of manufactured fibers is controlled during production.
Denier is the weight in grams of 9,000 meters of a fiber or yarn.
Fibers may be solid or hollow. Their surfaces may be smooth or textured. The cross sectional shape and surface contour of natural fibers is a result of how the fibers grow. The shape and surface contour of manufactured fibers is controlled during production.
Crimp is twists, curls, or coils along the length of a fiber. Crimp affects hand, cohesiveness, resiliency, stretch, bulk, heat retention, abrasion resistance, and absorbency. Crimp exists naturally in wool, and it can be added to manufactured fibers.
Properties:
Abrasion resistance is a fiber’s ability to resist damage from rubbing.
Absorbency (or moisture regain) is a fiber’s ability to take up moisture.
Chemical reactivity describes how a fiber responds to specific chemicals such as acids, alkalis, oxidizing agents, and solvents.
Density (or specific gravity) is the measure of the mass of a fiber per cubic centimeter. Specific gravity is the ratio of a fiber’s density to that of water (which has a density of 1g/cc at 4oC). Fibers with a specific gravity less than 1 float, while those whose specific gravity is greater than 1 sink.
Dimensional stability describes a fiber’s ability to retain a size and shape.
Drape describes how a fiber hangs over a three dimensional form.
Dyeability is a fiber’s ability to take up and retain dyes.
Elasticity is the ability of a fiber to return immediately to its original length.
Electrical conductivity is the ability of a fiber to transfer electrical current. Fibers with high electrical conductivity do not develop a static charge.
Elongation measures how much a fiber may be stretched without breaking.
Flammability is a fiber’s ability to burn. It describes how the fiber reacts to ignition sources, and at what temperature the fiber will ignite (if it is inflammable).
Hand describes how a fiber feels. Is it smooth, harsh, silky, dry, clammy, etc.?
Heat conductivity (or thermal retention) is the ability of a fiber to retain or transfer heat. It describes the insulation properties of a fiber. Fibers with low heat conductivity (high thermal retention) are good insulators.
Heat sensitivity describes how a fiber reacts to high heat. Does it shrink, soften, melt, discolor, or ignite if exposed to high heat, and at what temperature will it do so?
Loft is the ability of a fiber to spring back to its original thickness after being compressed.
Luster is the amount of light reflected from the surface of a fiber.
Mildew resistance describes a fiber’s ability to resist the growth of mildew, mold, and fungus.
Moth resistance is a fiber’s resistance to insect damage. It describes which insects (if any) will eat the fiber.
Pilling is the formation of balls of fiber (pills) on the surface of a fabric.
Resiliency is a fiber’s ability to return to its original shape after bending, twisting, and crushing. Fibers with high resiliency resist wrinkling.
Shrinkage resistance is a fiber’s ability to retain its original size through use and care.
Sunlight resistance is a fiber’s ability to withstand damage and discoloration from sunlight.
Tenacity is a fiber’s strength measured in grams per denier. The breaking tenacity of a fiber is the force required to break the fiber. Moisture affects a fiber’s tenacity, so the breaking tenacity is measured both dry and wet.
Texture is the nature of a fiber or fabric surface. It describes the way a fiber or fabric appears.
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