Midterm 1 Study Guide
Midterm 1 Study Guide TXC 006
Popular in Introduction to Textiles
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Chaya Botsford II
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This 22 page Study Guide was uploaded by Demi Chang on Monday October 12, 2015. The Study Guide belongs to TXC 006 at University of California - Davis taught by Sun, Gang in Fall 2015. Since its upload, it has received 92 views. For similar materials see Introduction to Textiles in Textile and Apparel Management at University of California - Davis.
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Date Created: 10/12/15
TXC 006 Introduction to Textiles lecture Reading Notes Lecture 1 3 Textile materials may consist of yarns fabrics and products created from fabrics that retain more or less of the complete strength and exibility and other normal properties of original laments or bers Egt Strength usually refers to hard goods such as textiles used in wearable technology gadgets etc Flexibility on the other hand usually refers to soft goods such as fashion apparel and clothing gt The original bers are often characterized as exible and capable of covering a high surface area gt Fibers are the basic element in construction followed by yarns which is made of ber and fabric made of yarn Chemicals and colorants may also be used as well 3 Textile Performance serviceability This evaluates a textile39s ability to ful ll the needs of the consumer Textile Performance can be categorized under EgtAesthetics a textile product39s appearance or attractiveness Egt Durability a product39s ability to withstand use the appropriate length of time the textile is usable from the time it was bought While durability is currently not considered a major factor in fashion apparel it is an important attribute for textiles in institutions such as hospitals Egt Comfort how a textile interacts with moisture air heat and the human body gt Maintenance maintaining the product to its original appearance when caring and using it For example a shirt may often require ironing to prevent wrinkles This also refers to are the required treatment to maintain the textile39s original look For example silk would speci cally require a hand wash because it would be ruined in the washerdryer Egt Protection health safety the textile39s ability to protect someone39s body from unwanted substances and the environment 3 Fibers can refer to a manufactured or natural substance that has a length of at least a hundred times its diameter or width and has the ability to be made into yarn and yarn into fabric Fiber diameters may range from eleven to fty micrometers but generally the ratio of its length to width is 1000 1 When looking at different crosssection of bers each type will often have a distinct cylindrical shape However each is structured differently wool looks more like overlapping striped layers while cotton has a more spiral shape Fibers can be categorized under gt Short ber STAPLE Examples of short ber include wool cut lengths of ligament and cotton Staple bers are traditionally used in apparel textiles though the use in different industries has expanded Egt Continuous ber FILAMENT Examples of continuous ber include synthetic and silk bers 3 Yarns refer to an arrangement of bers that can be twisted together to create a strand that is made into fabric Fabric can be constructed through different arrangement of ber and yarns within a fabric such as interlacing woven fabrics interlooping knitted fabrics and bonding nonwovens the laments bers These different arrangements of yarns bers within a fabric refers to the process known as fabric construction Egtlnterstices are considered the voids or spaces within a fabric 3 Fabrics are considered planar structures that is made from bers and yarns They tend to be very porous because of the interstices between yarns and bers often 6090 air by volume and may be nished with chemicals or colorants 3 Colorant and Chemicals are also often used on fabrics as well Colorants include dyes which are mostly soluble or able to dissolve in water and pigments insoluble while Chemicals may refer to surfactants acids bases and nishing agents Note that colorants alters the object39s color while coloris the nonphysical result of the colorant39s alteration 0n the other hand chemicals can often ll interstices and sometimes become an adhesive for the material39s layers Chapter 1 Additional Reading Highlights 3 Fabricated textile product enduse product is formed by a manufactured fabric into consumer items like apparel carpeting draperies lters and tents These products are often created by sewing speci callycut pieces together Fabricated textile products are mainly sold in these four markets gt Apparel This market involves any items used to be worn This includes children wear lingerie pants blouses skirts Tshirts tops shorts swimwear suits athletic wear men39s and women39s wear Egtlnterior Textiles A market of products that are used for surface treatments in commercial buildings and homes such as curtains draperies carpeting wall coverings and upholstery Textiles speci cally used for buildings in public government buildings corporate of ces theaters nursing homes are designed to be more durable to withstand more wear These textiles are known as contractinterior textiles gt Institutional and Household Textiles With the exception of interior textiles these products are utilized within the home including mattress sheets pillowcases blankets towels and and tablecloths These same products used in public places create the institutional textiles market Egtlndustrial and Consumer Textiles These include automobile safety belts tents roofs tanks and lters beatextiesare used in soil applications like dams road buildings and controlling erosions Protective gear for pouring metal ghting re and cleaning chemicals are also part of this market Industries related to construction sanitation transportation aerospace shing mining military and medicine often acquire different industrial textile products as well Consumer Textilesrefers to recreational products like backpacks rackets balls and umbrellas 3 Closely related Materials that differ from textiles but have a similar thin brous exible and sheetlike structure include paper leather and fur These structures are not capable of being textile fabrics because paper bers are too short leather bers cannot be separated and fur bers cannot be taken off the pelt Lecture 2 3 Classi cation of Fibers include natural bers and manmade bers EgtNatural bers include vegetable bers seed bast and leaf animal bers and mineral bers A common seed bast and leaf include cotton ax and manila respectively Common animal bers include wool silk and animal hair like alpaca cashmere and camel However some animal ber acquisition is considered an illegal trade due to animal cruelty Also a well known mineral ber is abestos EgtManmade bers include inorganic bers glass metal ceramic regenerated bersRayon Casein Lyocell semisynthetic bers cellulose acetate and synthetic bersNylon Acrylic Polyester and Spandex Manmade bers is part of many relatively new and expanding industries such as sportswear 3 Morphology is the study of structure size and shape of a material and the relationships between aspects of structure what it looks like and its physical properties Fiber Morphology includes four speci c structures in descending order of size macrostructure microstructure submicroscopic structure and ne structure EgtMacrostructure refers to the features of ber structure that are plainly visible and observable by the eye Macrostructure refers to length size crimp and color 1 The length of staple bers vary from 246 cm while laments can be in nitely longer Anything shorter than 15 mm is considered a nontextie ber which is used for other products 2 Size is measured in terms of the ber39s diameter also known as linear density or crosssectional area The more ne the natural ber size is the higher quality it is cashmere is ner than regular wool creating the extremely soft feel The diameter of natural bers are measured in micrometer pm and range anywhere between 1170 pm Manmade and silk bers however are measured in denier or tex units Manufactured bers can be classi ed under the sizes ne medium coarse micro ber ano utra ne micro ber Denier refers to the weight grams of 9000 meters of a linear material 1 denier 1 g of 9000 m of ber lf 9000 m of a different ber weighs more than 1 g that means this ber is coarser larger in size Denier is a smaller unit in comparison to Tex PU Tex is the weight grams of 1000 meters of a linear material 1 Denier 19 Tex If a ne ber is 22 denier then to gure out the equivalent in tex units divide 22 by 9 24 tex lf medium ber is 70 tex then to gure out the equivalent in denier units multiply 709 63 denier 3 Macrostructure can also refer to a crimp the shape along a ber length that may be waves twists curls or bends Crimps can help the binding force between bers Crimps can be 2 or 3 dimensional as well as inherentor latent Inherent crimpsare developed naturally in the ber or as it forms during spinning latent crimpsare developed after the ber is formed by exposing it to moisture or heat 4 The color of natural bers are often offwhite white brown or tan Natural bers like cotton can also be naturally colored also known as Fox Fibre Cotton Manufactured bers are also generally white and offwhite but the color is changeable 3 Microstructure refers to ber features that can be seen underneath a light microscope Microstructure encompasses longitudinal form surface contour and cross sectional shape gt Natural bers have a rodshaped and ribbon shaped longitudinal form an irregular surface contour and a cross sectional shape determined by nature Egt Manmade bers have even and uneven length longitudinal form smooth surface contour and a manufactured cross sectional shape Also cross sectional shapes can be oval round elliptical serrated trilobal or even kidney bean shaped 3 Submicroscopic structure refers to ber features that can be seen underneath an electron microscope This microscope has a higher magni cation than a light microscope which is used to determine a ber s microstructure gt Natural bers have very individual submicroscopic structures for example wool as a cortex cuticle and medulla 0n the other hand Egtmanufactured bers are known for their skincore feature a thin outerringed skin and a large core body in the middle 3 Fine Structure describes the polymers that make up a ber and their arrangement within the ber Fine structure begins to delve into the chemical structure of a ber Fine structure focuses on polymers monomers and also the organics or the carbon chemistry of a polymer and monomer Egt Polymers are large molecules that consists of repeating units of monomers linked by covalent chemical bonds Most bers are organic polymers Egt Monomers are mainly organic compounds with carboncarbon double bonds and other additional reactive groups gt Organics refers to carbon carbon chemistry and most organic compounds including hydrogen H oxygen 0 carbon C nitrogen N and the halogens Br I F Examples include methane CH4 benzene acetylene and ethane Ethanol and acetic acid vinegar can be combined to create ester the component used to create polyester Acetic acid can also combine with Amine to create Amide which can become nylon If a polymer is a structure of ballandstring the ball would be the monomer and the string would be the covalent bond linking the monomers together Lecture 3 3 Fine Structure cont Textile Fibers are comprised of three polymer types homopolymers copolymers and block polymers EgtHomopolymers have one monomer repeat itself on the polymer train Examples include cotton wool silk polyester and rayon A visual 000000 2gt Copolymers include two or more monomers in a polymer chain such as acrylic saran bers and vinyon A visual O O O O O EgtBlock polymers have blocks made of homopolymers repeated along the polymer chain A common block polymer is Spandex or Polyurethane A visual OOOOOOO 3 The Degree of Polymerization refers to how many times a monomer repeats itself in a polymer chain usually the number is an average length of the polymer chain The average length depends on the distribution of the length of polymer chains The more narrow the distribution of polymers the better it is because that means the molecular weight of each chain is approximately the same If there is a high degree of polymerization then there are lots of chains and thus creating a stronger textile 3 Orientation refers to the degree of parallelism of chain molecules that are part of linear polymer structures The higher the parallelism the stronger it is 3 Crystalline regions are made of of crystals that have regions in the lattice structure They comprise of an orderly structure that is quite opposite from amorphous polymers The orderliness of crystalline parts means that they have a high degree of parallelism 3 Amorphous regions are noncrystalline forms that are present in the disordered region of polymers The disorderly nature of amorphous parts means that they have a low degree of parallelism Textiles are often made to have both crystalline and amorphous qualities to have a combination of both the strength and exibility of each More crystalline bers are stronger stabler and more chemically resistant but they are stiffer less absorbent and dif cult to dye as well 3 Intermolecular Forces or the Intra berInterpolymer Forces between polymers in bers include EgtElectronegativity is the tendency for atoms to attract electrons the more an atom attracts electrons the more electronegative it is Cl 0 and N are very electronegative and on the same level of electronegativity followed by C and H gt Polar and Nonpolar covalent bonds are shared bonds that share electrons with each other Nonpolar bonds include two elements that are on the same level of electronegativity like C and H while polar bonds include two elements that are on different levels of electronegativity like C and 0 Polarity occurs when electrons are unequally shared Egt Ionic bonds electrostatic bonds happen between positively and negatively charged elements also known as satinksbria ges A common example is Na bonding with Cl creating table salt Ionic bonds are not covalent bonds These bonds form between polymers in protein bers and nylon polymers Egt Covalent crosslinks are individual covalent bonds between polymer chains aside from the bonds between monomers on the polymer backbone Egt Hydrogen bonds are bonds that only occur between hydrogen atoms that covalently bond with strong electronegative atoms like F N and 0 It is the strongest type of dipoledipole interaction Hydrogen bonds are slightly positive while the other atoms of 0 N or F are slightly negative Important use of hydrogen bonding can be seen in cellulosic bers rayon ax and cotton nylon and protein bers silk and wool D Van Der Waals Forces are weak electrostatic forces that occur in nonpolar or neutral molecules It only occurs with polymer segments that lie close together This force often occurs in the crystalline regions of a ber The larger the atom size the larger the Van der Waals Force Egt DipoleDipole Interaction attracts the positive end of a polar molecule for the negative end of another polar molecule For example the positive hydrogen end of a molecule is attracted to a negative chlorine end in hydrogen chloride DipoleDipole Interaction has a stronger bond for polar molecules than it does for nonpolar ones It is also a major force in the bonding of acrylic bers and polyester TXC 006 Introduction to Textiles lecture Notes lecture 4 3 Hberformation Fiber Spinning is a process where synthetic bers are made by forcing a molten liquid polymer through a spinneret with a thousand holes A spinneret is similar to a faucet head with the tiny holes for water to lter through though ber is produced instead of water Three common spinning processes include EgtMelt Spinning The molten polymer is extruded through the spinneret to create brous forms of polymer that solidify in cool air Melt spinning is used for thermoplastic polymers which can be melted from solid to liquid and vice versa making it an easily processed material Textiles formed through melt spinning include nylon polyester and ole n ber Fiber spinning is a relatively simple ber spinning process that requires to solvent produces no water pollution and its product can be recycled Egt Dry Spinning The polymer dissolves into an organic solvent to become a polymer solution This solution is forced through a spinneret into a circulating current that evaporates the solvent from the polymer to cause the bers to harden The solvent can then be reused recycled Dry Spinning creates textiles like acrylic ber and Spandex It does not contribute directly to water pollution and is ideal for polymers that can molecularly separate at low temperatures Egt Wet Spinning The polymer dissolves into a water solution solvent and is forced through ajet into a liquid bath where the laments thicken Wet spinning can create rayon acetate and aramid bers Acrylic which can be created through dry spinning is also able to be created through wet spinning as well Wet spinning is the most problematic process because it produces water pollution and toxic chemicals 3 Otherfxtrusion ProcessesThese processes include EgtGel Spinning A diluted syrupy solution of high molecular weight polymer is pushed through ajet in uid form at the extrusion temperature The gel form of the bers is cooled and processed after Gel spinning is often used for nonapparel bers such as for textiles in bulletproof vests and seat belts or textiles requiring the strongest ber High MW Molecular Weight polyethylene ber a textile used in body armor and parachutes also uses gel spinning Egt Reaction Spinning This process causes the polymers to form together as it39s being pushed out of the spinneret 3 Fiber Properties include Mechanical Sorptive Thermal Chemical and Miscellaneous properties EgtMechanica Properties refer to a ber s response to applied forces and how the ber recovers from those forces The overarching mechanical property is Durability or a ber39s ability to retain its physical shape under mechanical stress for a reasonable time period Properties under durability include 1 Stress a ber s resistance to deformation as it is being subjected to a pullingtensile force This resistance creates a change in the ber39s length Stress is measured in units of N newtonstex or g gramsden 2 Strain The deformation of a ber that is caused by applying the pullingtensile force Deformation refers to the lengthening or extension of the ber similar to a stretched and elongated rubber band Strain is measured as a percentage which is calculated by Change in lengthoriginal unstretched length100 Tenacity at Ereahjl a m E quot E quot quot quotquotquotquot quotquot quotquotquotT T quotquot L 39 quotl The polymer chains begin tn straighten The chain molecue aleng the ber anis beins tn straighten its arrangement as it stretches 2 chain molecules begin to slip causing the fiber tn became Inngen as the E w 7 pnlymeir deferms Ann fiber pullledl pass Area Em I ma Z w the yield nint will fall bath e last39c I T t W w h a p necesery me After the yield paint the E A i I if if can walk f imaterial begins tn nae tn the force and w p 39 TEE TEE J I Rupture I more defnir mation accurs even though I 139 3 m3 ma 3 v 2 the force is being applied at the same g a if Hecnaered Wench Area lincpgaginy rate 3 a 39 nnj in at Brea f I ll Lg bl quot i Elongation 1 Strain liii Initial E Yigld Hardening lD Rupture Stness5train Enrae Modulus Pint paint Pint ElemRemains 3 Tenacity The stress expressed as force per linear density can be measured in gramsforce per denier or Newtons per tex Breaking tenacity or tenacity at breakquot in graph above is the level of tenacity in which the ber ruptures The higher the orientation degree of polymerization and crystallinity the higher the breaking tenacity For example ax and ole n have high breaking tenacity while wool and acetate have low breaking tenacity 4 Elongation The ber39s ability to extend lengthen which is expressed as a percentage of its original length change in lengthoriginal unstretched length 100 Breaking elongation or elongation at breakquot in graph above refers to the elongation when the ber ruptures The higher the crystallinity the lower the break elongation While wool and nylon have high elongation cotton and ax has low elongation 5 Initial Modulus The rst segment of the stressstrain curve is the straight line Aquot in graph above where stress is proportional to strain as the force is being applied at a steady positive rate the strain of the ber increases at a steady positive rate as well The line39s slope stress strain measures the ber39s initial modulus or Young39s modulus The higher the modulus the harder it is to elongate For example cotton has a high modulus making it a dif cult textile to elongate while rayon has a low modulus making it easier to elongate Higher modulus textiles tend to be higher in crystallinity and molecules while lower modulus textiles are more exible and softer 6 Work of Rupture Toughness A ber39s ability to endure large deformation without rupturing This is measured by the area under the stressstrain curve areas XYZ in graph above Polyester and nylon are tough bers therefore their work of rupture encompasses a larger area underneath the stressstrain curve 7 Yield Point The point where the stressstrain curve attens and the molecules permanently deform Bquot in graph above If a textile is stretched before the yield point 1quot in graph above then the textile will return to the initial modulus However if it is stretched beyond the yield point 2quot in graph above then the textile will fall to the elastic recovery curve lecture 5 8 Elastic Recovery A ber39s ability to return to its initial length after being stressed elongated Spiraledfolded polymer chains tend to create a springlike property Textiles with more hydrogen and ionic bonds may reduce the elastic recovery For one Nylon as good elastic recovery while rayon does not 9 Resilience work recovery A ber39s ability to spring back after being extended It is expressed as the ratio of recovered work X to total work XY in graph above needed to deform and release the ber Crimped bers are more resilient than smooth bers Hydrogen bonds lower the level of resilience The higher level of resilience the more wrinkle resistant the textile is For example polyester nylon and wool have the highest degree of resilience which is why nylon and wool are used for carpeting completely wrinkleprintfree Cotton and rayon which have the lowest degree of resilience would be easy to make imprints in if they were made into carpeting 10 Stiffness exural rigidity A ber39s resistance to bending or its ability to carry loads without deforming lengthening Fibers3929 in terms of dentex and crosssectional shape can affect the ber39s stiffness The bigger the size in dentex the coarser the ber is The coarser the ber the stiffer it is The smaller the size the ner and less stiff it becomes Spectra ole n ber has the highest stiffness while Spandex has the lowest stiffness 11 Abrasion Resistance A ber39s ability not to break crack or wear away under a rubbing force or friction Textiles like nylon has the highest abrasion resistance making it ideal for making backpacks Textiles like Acetate has very low abrasion resistance which is why it is made to create women39s delicates night gowns 12 Flexibility The number of times a ber can be bent without rupturing The higher a ber39s crystallinity the less exible it is Polyester has high exibility while carbon has the lowest exibility gt Sorptive Properties 1 Moisture RegainVaporous Water Absorption The percentage of moisture a ber contains when placed an environment This is calculated by its dry weight or the weight of the ber when it contains no water at all If W1 is the ber39s weight in a humid environment and W0 is the ber39s dry weight then the change can be calculated by W1W0 W1 Sorptive properties affect the textile products weight and its commercial use The more polar hydrogen bonds the higher the moisture regain natural bers have high moisture regain while synthetic bers have low moisture regain A Hydrophilic water loving textiles like cotton have more polar and hydrogen bonds B Hydrophobic water avoiding textiles like polyester do not absorb water well C Hygroscopic textiles that absorb moisture in large amounts without feeling wet to the touch such as wool and sports clothing eg the synthetic ber Coolmax 2 Swelling Liquid Water Absorption The increase in a ber39s size crosssectional area or length when it is immersed in water It is measured as a percent increase in diameter or length The wetmoa uus is when the ber is at maximum water absorbance While rayon has a high swelling effect which is why it can not be washed like other apparel textiles nylon as the least swelling effect A wet ber can often have different tenacity mechanical properties than the dry ber While linen and cotton have higher wet tenacity textiles like silk wool and nylon are weaker when wet 3 Heat of Wetting The heat produced when a ber absorbs water when a ber absorbs water heat is created from the attractive force between the ber and the water molecules Hydrophilic bers have higher heat of wetting Wool for example has the highest heat of wetting it is often used to make hiking socks because the sweat will make the skin feel warmer even in extremely cold weather 4 Oil Absorption Amount of oil adsorbed held as a thin lm on the outside surface or absorbed by a ber Oil can refer to oils from food the body cosmetics or soil Oleophilicity refers to a ber39s ability to release oily soil when placed in a solution of detergent Cotton a hydrophilic textile has the highest oil absorption and easiest oil release Polyester a hydrophobic textile has the lowest oil absorption and hardest oil release gtTherma Properties 1 Thermal Conductivity the rate of heat ow that occurs along the ber 2 Heat Resistance Heat Durability The ber39s temperature as it begins to degrade break apart 3 Glass Transition Temperature Tg The ber39s temperature when it changes from glass to a rubber state 4 Softening Melting Temperature The temperature that thermoplastic ber softens and changes from a solid state to a liquid state 5 Decomposition Temperature The temperature where a ber39s polymer structure loses its chemical identity a higher temperature than Heat Resistance Thermoplastic bers are soft when heated and hard when cooled lecture 6 6 Combustibility a ber39s ability or inability to ignite making it either combustible or noncombustible Naturally ame resistant bers include Nomex and Modacrylic while modi ed ame resistant bers include wood cotton and polyester 7 Resistance to Chemicals A ber39s stability in regards to its interaction with acids bases and organic solvents For example rayon ax and cotton are very vulnerable to acids like sulfuric acid and hydrochloric acid 0n the other hand wool and silk are extremely vulnerable to bases like alkaline Exposure to these solvents can reduce breaking tenacity and other mechanical properties gt Miscellaneous Properties 1 Resistance to UV Light short or high energy wavelengths in sunlight uorescent lights can break covalent bonds in polymers Manmade bers can be altered in its size crosssectional shape and delustrant amount to resist degradation by UV light 2 Resistance to Microorganisms Natural bers are the most likely to face deterioration from biological organisms especially in warm humid areas while synthetic bers are less likely to face deterioration Geotextiles which are often associated with soil and used in drains and roads also face this problem as well 3 Electrical Resistance Fibers with higher moisture content have lower electrical resistivity or lack of a static charge This is becoming more important today with the presence of wearable technology where clothing are being used as ways of conducting or generating energy and connecting it to mobile devices 4 Speci c Gravity density The ratio of the ber39s mass to the mass of water at equal volume and at 392 degrees Fahrenheit m mass v volume Speci c gravity ranges in value between 09 to 151 3 Textile Labeling EgtThe Three Major Laws in textile labeling are 1 WPL Wool Products Labeling wool textile products both 100 wool or wool blends must be labeled 2 TFPIA Textile Fiber Products Identi cation Act Fibers other than wool that are made into apparel interior household consumer and industrial products or sold overthecounter must have labels 3 Care Label Rule This rule only applies to apparel or certain piece goods Things like upholstery sewing threads apparel paddings and surgical dressings are exempt from this rule gt The Standard Terminology and Labeling on all apparel and piece good labels include these ve items names of ber content ber composition in terms of percent of total fabric the manu rcturer39sname country of origin and the care instructions 1 Generic names manu rctureo bers and common names natural bers are the only names allowed to be used to de ne the ber content Some examples of generic bers include acetate acrylic aramid Kevlar Nomex glass metallic modacrylic nylon ole n polyester rayon rubber and spandex 2 The percent composition only has to be listed by its common generic name if the ber more than 5 of the weight Fiber content is listed from highest to lowest eg 55 cotton 35 polyester 10 acrylic 3 The manurbcturerlsname RN registered number or WPL number Wool Product Labeling should be labeled so the customer has the ability to contact the producer Numbers can be applied at the FTC Federal Trade Commission 4 The country oforgin can only have two countries at most be disclosed on all textile products in the US The four forms of country of origin include A Made in XOffshore Country The last country involved in substantially transforming the product before being imported to the US is the country name labeled on it For some products the country of origin is the last country to nish the manufacturing For cutandassembled it is the country that sews and assembles the textile For knitwear it is the country that produces the parts For dyeing it the country that produces the fabric B Made in the USA textile products are made completely in the US C Made in the USA of Imported Components The textile and product was made in the USA but the ber was from another country For example Made in the USA of silk ber imported from Chinaquot D Partially Manufactured in the USA and Partially Offshore The product may have been made in the USA but the ber and textile parts are from another country For example Imported fabric from Italy sewn in the USAquot Additional Chapter 7 Reading Highlights 3 Polymer Synthesis Polymerization for Synthetic Fibers EgtStep Growth or Step Reaction Where the formation of every covalent bond in the polymer is accompanied by a small byproduct molecule that is liberated often times water This occurs in the creation of nylon and polyester EgtChain Growth or Chain Reaction Addition Polymerization unreacted monomers are approached by a reactive initiator molecule A free radical is then produced which will most likely strike another monomer to create a polymer chain of identical monomer units 3 Drawing and Heat Setting EgtDrawing When polymers are extruded they are unoriented or undrawn meaning that they have a low degree of orientation crystallinity Filaments are drawn or elongated under heat to move them closer together EgtHeat Setting The heat stabilizes the synthetic bers and lowers the stress within the ber Modifying Manufactured bers can be achieved by changing the crosssectional shape surface contour degree of polymerization crystallinity incorporating chemicals in polymer chains adding monomers adding reactive groups and making biocomponents two polymers that are chemically physically different TXC 006 Introduction to Textiles lecture Notes lecture 7 7quot Natural bers can be split into two groups Protein bers and Cellulose bers Protein bers derived from animals include wool a staple ber and ilk the only natural ber that is a lament Cellulose bers derived from plantbased materials include cotton and g 3 Wool Fibers can be obtained from eece of lamb or sheep and hair of Angora or Cashmere goat Fibers may include camel alpaca llama and vicuna hair Australia is the main producer of wool Speciality wools include Mohair Cashmere llama and alpaca D Macrostructure 1 Length 1515 inches making it a staple ber 2 Size 1470 pm micrometers While long ne wool called tops is commonly used for apparel long coarse wool is often made into carpeting 3 Crimp Threedimensional 4 Color brown or offwhite Offwhite cream is the most popular coloration D Microstructure 1 Scales are the main component in the cuticle there can be 7002000 scales per inch of ber 2 It has an oval elliptical crosssection and 3 A hollow canal in the center of the ber called the medulla EgtSubmicroscopic Structure 1 Epicuticle A waxlike nonprotein and thinlayered substance that covers the scales of a wool ber 2 Cortex This has countless numbers of long spindleshaped cells that form 90 of the ber39s volume The cortex consists of Orthocortex and Paracortexquot two distinct sections of the cortex that spiral around each other along the ber The spiraling also creates wool39s unique 3D crimp The irregular waviness of the ber increases the wool39s cohesiveness elasticity loft and yarn strength Orthocortex and Paracortex are considered sidebyside bicomponents where the sections are sidebyside but they have different behaviors ie different reactions to moisture and temperature 3 Cortical A brillar small slender spiral structure that is made of macro bris Each macro bril is composed of micro bris which are made of proto bris and every protofrbril has three keratin polymer chainsthat spiral around each other The spiral structure increases the ber s exibility elongation elastic recovery and tenacity D Fine Structure 1 Keratin Polymer A crosslinked protein with an orhelix structure that consists of amino acids The polymer is 2530 crystalline and 7075 amorphous in its regions making the ber more stretchy While the ber39s structure is pretty straight like packed spaghetti the orientation is low because the quotspaghettiquot or ber structure is all curved Amino acid oramino acids with a structure of amine group I carbonyl groin p A R refers to the rest of amino acid which differs with each type B Common amino acids in wool include Glutamic Acid Cystine Serine Glycine and Arginine C Intermolecular forces forces between molecules as opposed to the forces holding a molecular together in wool include hydrogen bonds and cystine linkages Hydrogen bonds contribute to the ber39s strength elasticity and its reaction to moisture Cystine is found in hairwool hair and is bound by the cystine crossink where two cystine amino acids on two adjacent chains are covalently bonded by two sulfur atoms also known as a disul de bond This is why cystine would release a sulfuric smell in a burning test 3 Peptide bond The chemical bond between the carboxyl and amino groups of neighboring amino acids This is the primary link that binds all protein structures 3 Properties of Wool DAesthetics Wool is odorless resists wrinkles in maintaining its appearance high resilience low luster low pilling unsightly fuzzy surface from wear and loft air in ber D Durability Fabric has high durability moderate abrasion resistance low tenacity and very excellent elongation exibility and elastic recovery D Com fort High heat of wetting hygroscopic excellent insulative ability poor heat conductor and low rate of bodywater evaporation D Maintenance It can easily release soils has high elongation low tenacity when wet shrinks when it is agitated by water known as felting it degrades in chlorine bleach dryclean recommended and is easily attacked by moths beetles wool is naturally biodegradable 3 Silk Fibers are strong ne laments that are made by larvae of insects like silkworms D Macrostructure 1 length Averages 328 yards but can reach a maximum of 656 yards 2 Size 12515 denier or 1230 pm 3 Crimp None straight 4 Color Translucent white known as degummed bers D Microstructure The surface shape is 1 Uneven in its diameter 2 An irregular surface 3 ultivateo sik has a triangular crosssectional shape while wildsll has a rectangular crosssectional shape 4 Contains a coating of sericin thatjoins two silk laments together D Submicroscopic Structure 1 Cultivated silk has no identi able structure while wild silk has an internal brillar structure D Fine Structure 1 Silk polymer consists of a protein polypeptide that is made of different amino acids called broin The most common amino acids in silk include Glycine Alanine and Serine 2 It has a pleated psheet structure with 7075 crystalline and 2530 amorphous regions 3 Properties of Silk EgtAesthetics Soft luster with a little sparkle after degumming because of the high crystallinity and the triangular crosssection it makes a rustling sound and medium resilience Egt Durability It has the highest tenacity of all protein bers high orientationcrystallinity medium elongation at break and elastic recovery and high toughness D Comfort Smooth soft cool hydrophilic and hygroscopic high absorbency and heat of wetting but lower than wool D Maintenance Moderate resistance to wrinkling no shrinking loses tenacity by 20 when wet degrades in mild alkaline discolorsscorches under heat dryclean recommended Mechanical Properties Wool Silk Tenacity Low Medium for breaking tenacity Elongation High Medium nitia Modulus Low Medium Elastic Recovery High Medium Flexibility High Abrasion Resistance LowMedium Medium Stiffness Low Medium Resilience High Medium Toughness Low High Sorptive Properties Wool Silk Moisture Regain High High CrossSectional Swelling Medium Medium Heat of wetting Highest High Effect on Mechanical Prop High High Oil Absorption High Ease of Oil Release High Thermal Properties Wool Silh Heat Resistance High Low Softening Melting High High Decomposition High Combustibility Low Low lecture 8 3 Cotton Fibers is a ber derived from seed that meets more than 50 of the worldwide demand for apparel ber Native to tropicalsubtropical regions this plant is produced mostly by China India and US Texas and California leads the US 5 important cotton types include Egyptian Sea Island American Pima Asiatic and Upland D Macrostructure 1 Length short staple ber Shorter bers are not suitable for textiles Longer and ner bers have better quality and are more suited to making textiles 2 Size 1620 pm micrometers 3 Crimp twisted ribbon 4 Color white or offwhite Offwhite signi es higher quality D Microstructure 1 Surface Shape at twisted ribbon A ber can have 125 twists or convolutionsper inch along the ber length 2 CrossSectional Shape Mature cotton has a kidney bean shape others may be circular or elliptical DSubmicroscopic Structure 1 Cuticle waxy layer protecting cellulose The scouring process is used to remove this layer 2 Primary Cell Wall It is a sheath of spiraling brils Each layer spirals 2030 degrees to the ber axis Mature bers have thick primary walls while immature bers have thin ones 3 Secondary Cell Wall The central layer of spiraling brils within the primary cell wall It has a higher level of orientation than the primary cell wall 4 Lumen A hollow canal along the ber39s length It accounts for V3 of the space in a cotton ber As it matures the lumen collapses inward creating the kidney bean shape D Fine Structure 1 The cellulose polymers are made of pDglucose and contains a lot of 0H hydroxyl groups 2 High Degree of Polymerization 600010000 3 More Crystalline 6570 and 3035 amorphous 4 Intermolecular Forces Hydrogen Bond links occur between the six carbon39s hydroxyl group and between the oxygen linking the two rings DipoleDipole and Van der Waals is also present 3 Properties of Cotton DAesthetics The crosssectional shape and ber twists create a low luster It has a low resilience D Durability Moderate tenacity and initial modulus and it becomes stronger when wet It also has low elongation at break and elasticity D Comfort It is extremely comfortable due to its high absorbency soft due to its naturally tapered nature of the ber39s end D Maintenance Low resilience makes it prone to wrinkling It shrinks in water vulnerable to strong acids can be ironed at a high temperature and is vulnerable to silver sh attack 3 Flax llinenl Fibers are taken from the inner bark of a plant39s stem grown in temperatesubtropic regions worldwide tinenis made from ax a fabric known for its crispy feel and irregular thickandthin surface D Macrostructure 1 length Long bers known as line and short bers are called tow 2 Crimp None 3 Size 24 times the size of cotton 4 Color Light to Gray Blond D Microstructure 1 Surface Shape cross marks called nodes 2 CrossSectional Shape polygonal cells called ultimate irregular D Submicroscopic Structure 1 Cell Wall Fibrils have cellulose spiraling at a 6 degree angle to ber axis 2 Lumen is present D Fine Structure 1 The cellulose polymers contains a lot of 0H hydroxyl groups 2 Higher Degree of Polymerization than Cotton 3 Slightly less Amorphous than cotton 4 Intermolecular Force Hydrogen Bond 3 Properties of Flax DAesthetics Naturally high luster that can be lowered by the irregular ber bundles It is stiffer harsher in comparison to cotton D Durability While Flax is stronger than cotton because of its higher degree of orientation it has poor elasticity and elongation and less exible than cotton D Comfort It has a cool feel dries very quickly and a high absorbency level D Maintenance High resistance to mildew and heat more dif cult to bleach in comparison to cotton Mechanical Properties otton Flax Tenacity Medium Medium Elongation Low Low Initial Modulus Medium Medium Elastic Recovery Low Low Flexibility Low Low Abrasion Resistance Medium Stiffness Medium Resilience Low Low Toughness Low Low Sorptive Properties otton Flax Moisture Regain High High CrossSectional Swelling Medium Medium Heat of wetting Medium Effect on Mechanical Prop High High Oil Absorption High Ease of Oil Release High
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