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Various Methods for Analysis of Textiles-fibre Content, Yarn and Fabric Structure

Presented By:Mona VermaPh.d. Research ScholarDeptt. of Textile and Apparel Designing, CCSHAU,HISARmona.verma35057@gmail.com

Importance of analysis of fibre content ,yarn and fabric content:

Fibre identification is an important first step in predicting the behavior of a textile artifact in various environments.

Knowing the identity of the fibre is also helpful in planning appropriate conservation treatment or storage methods.

The procedure of identification of the fibre content of a fabric depends on the nature of the sample, the experience of the analyst, and the facilities available. Because laws require the fibre content information presented with the displayed material in the museum or in the labeling done on the articals.

Several factors can complicate the identification of fibres within a textile artifact:

The poor condition of a degraded historic textile may make it difficult or even impossible to identify the characteristic diagnostic features of fibres.

Yarns that are blends of two or more fibre types, including man-made fibres, can complicate the interpretation of the results of burn tests. Consequently, another test method such as microscopic examination of fibres should be used to confirm the results of the burn test.

Neither a burn test nor a microscopic identification is regarded as conclusive on its own, but either can be used as a confirmatory test.

Methods of Fibre Content Analysis:

Visual inspection method: by using appearance and feel

Burning test method

Solubility test method

Microscopic method

Visual inspection method

Visual inspection method

Visual inspection of fabric for appearance and hand is always the first step in the fibre identification.It is no longer the possible to make an identification of the fibre content by the appearance and hand alone because other other man made fibres also show the same feel and tough. So other test also used along with visual inspection test to confirm the identity of the fibres.This test only suits to the experienced analyst . But some times absence of the other resources. We use this method. However observation of the following characteristics is helpful.Length of the fibre: untwist the yarn to determine length. any fibre can be made in staple length ,but not all fibres can be filament. for example, cotton and wool are always staple.Luster and lack of lusterBody , texture, hand-soft to hand ,rough to smooth, warm to cool or stiff to flexible.

Burning Test Method

FibresWhen Approaching FlameWhen In FlameAfter Removal From FlameAsh OdorCelluloseCottonFlaxDoes not fuse or shrink from flameBurnsContinues to burn, afterglowGray feathery, smooth edgeBurning paperProteinSilk WoolCurls away from flameBurns slowlyUsually self extinguishingCrushable black ashBurning hairAcetateFuses away from flameBurns with meltingContinues to burn and meltBrittle blackHard beadAcridAcrylicFuses away from flameBurns with meltingContinues to burn and meltBrittle blackHard bead-Glass Does not burnModacrylicFuses away from flameBurns very slowly with meltingSelf extinguishing ,white smokeBrittle blackHard bead-NylonFuses and shrinks away from flameBurns slowly with meltingUsually self extinguishingHard gray or tan beadCelery-likeOlefinFuses and shrinks away from flameBurns with meltingUsually self extinguishingHard tan bead-PolyesterFuses and shrinks away from flameBurns slowly with melting; black smokeUsually self extinguishingHard black beadSweetish odorSaranFuses and shrinks away from flameFuses and shrinks away from flameself extinguishingHard black bead-Spandex Fuses but does not shrink from flameFuses but does not shrink from flameContinues to burn and meltingSoft black ash-

Solubility Test Method

SolventFibre SolubilityAcetic acid(100%),20C AcetateAcetone,100% ,20CAcetate, modacrylic,vinyonHydrochloric acid,20%Concentration,1.096 density,20 CNylon6 ,nylon 66,vinalSodium hypochlorite solution (5%) 20CSilk and wool(silk dissolve in 70% sulphuric acid 38C )azlonXylene (meta),(100%) 139COlefin and saran (saran dissolves in 1.4dioxane at 101C; olefin is not soluble),vinyonDimethyl formamide,(100%) 90 CSpandex, modacrylic, acrylic, acetate, vinyonSulphuric acid, 70% concentration, 38 CCotton, flax, rayon, nylon, acetate, silkCresol (meta),(100%) 139 CPolyester,nylon,acetate

Other Factors Which Affect Properties Of Fabric

FiberHeatAgeSunlightAcidsAlkalisInsectsMicro OrganismsElectrical conductivityCottonNo effect upto 1200C. Starts decomposing at 1500CLittle effect if stored properlyGradual loss of strength turns yellowAttacked by hot, diluter or cold conc. AcidsResistant. Swells in caustic soda but not damagedNot attacked by moths or beetlesAttacked by fungi and bacteria when dampGood insulator when dryWoolBecomes weak an looses softness decomposes at 1300CLittle deterioration if stored carefullyDecomposition with loss of strengthAttacked by sulphuric acid. Decomposes completely generally resistant to other mineral acidsDissolves in caustic soda. Soda and soap have to be used with careAttacked by moths and other insectsGood resistance to mildew and other insectsGood conductor of heat and electricitySilk Unaffected upto 1400C. Decomposes at 1750CSuffers gradual loss of strength Encourages decomposition Decomposed by strong acids. Mild acids have not effect Less readily damaged than wool dissolves in con caustic alkali May be attacked by moths Not usually attacked by mildew Poor conductor of electricity, used for insulation Viscose Begins loosing strength at 1500C. Decomposes above 1850CPractically no effect Good resistance prolonged exposure causes gradual loss of strength Attacked by hot, dilute or cold conc. mineral acids Resistant to dilute alkalis but strong ones cause swelling with strength lossResistant to insects, however attacked by silver fish Not readily attacked by mildew. Sever attack weaken fibers Poor insulator

FiberHeatAgeSunlightAcidsAlkalisInsectsMicro OrganismsElectrical conductivityAcetate Practically unaffected upto 1200C Melts at 2320C Slight fall in strength over prolonged exposure Slight deterioration after prolonged exposure Not affected by weak acids Conc. solutions of strong acids decomposes the fiber Dilute alkalis have no effect. Strong ones cause saponification Normally not attacked by moths and other insects High resistance bacteria may cause damage and discoloration Good insulator Triacetate (Tricel) Softens at 2250C melts at 3000C Highly resistant Highly resistant Good resistance Grater resistance to saponification than acetate Not attacked by moths and other insects Highly resistant to micro organisms Highly electrical resistance Polymide (Nylon)Unaffected upto 1500C Melts at 2500C Effect negligible Gradual loss of strength on prolonged exposure Hot mineral acids decompose nylon Not affected by alkalis Not attacked Not attacked Very good insulator

FiberHeatAgeSunlightAcidsAlkalisInsectsMicro OrganismsElectrical conductivityPolyester Excellent resistance to heat. Melts at 2600CPractically no effect Good resistance Gradual loss of strength after prolonged exposure Not affected by weak and moderately strong acids. Conc. sulphuric acid decomposes the fiber Good resistance to weak alkalis, but decomposed by strong, hot alkalis Not attacked Not attacked Excellent insulator Acrylic Excellent resistance to heat, starts sticking at 2550CNegligible effect Excellent resistance to sunlight Good resistance to mineral acids Good resistance to weak alkalis, but degraded by hot conc. alkalisNot attacked Not attacked Excellent insulator Poly-propylene Resistance good upto 1100C. Softens at 1600-1700C Little effect Stabilized fiber has excellent resistance Excellent resistance but affected slowly by conc. sulphuric and strong nitric acids Excellent resistance to conc. hot alkalis Completely resistant Not attacked Excellent insulator

Microscopic Appearance Of Fibre

Microscopic Appearance of Cotton

Microscopic appearance of silk

Microscopic Appearance of wool

Microscopic Appearance of Viscose Rayon

Microscopic appearance of polyester

Microscopic appearance of nylon

Test For Identification of Yarn

Direction of Twist

Twist is defined as the spiral arrangement of the fibres around the axis of the fibre. the direction of twist is described as s twist and z twist.A yarn has s twist ,if when held in vertical position, the spirals conform to the direction of slope of the central portion of the letter s.

It is called z-twist if the direction of the spirals conforms to the slope of the central portion of the letter z. Z twist is standard twist used for weaving yarns.

Yarns are twisted either to the right (Z-twist) at to the left (S-twist).the amount of twist is measured by the number of twist per inch( t.p.i.).

Low twist -0-3 tpiMedium twist -3-7 tpiHigh twist-7-12 tpiTwist count The amount of twist depends on the size of the yarn, the use to which it will be put and the length of fibres from which it is made.

Fine yarns requires more twist than coarse yarns.

The amount of twist in a yarn determines many of the characteristics. As yarn is twisted, it shortens and takes on potential strength .

High twist in crepes and georgettes produces much shortening of the yarn and gives possibilities of much stretchiness.

High twist also reduce luster.

Test Methods For Identification Of Fabric

Types of fabric: based on the method of construction the fabric is divided into various categories.

Woven fabric: a woven fabric consists of two sets of yarns which are interlaced at right angles to each other to produce a compact construction. Knitted fabric: in the knitted fabric the yarn is interloped. Only one thread is used in the knitting process. Wales and Courses are formed.

Nets : these nets are usually of nylon and are open mesh fabrics with large geometrics interstices between the yarns.

Laces: it is an openwork fabric consisting of a network of theads or yarns formed into intricate design.

Braided fabric: these have a diagonal effect ,made by plaiting 3 or more yarns that originate from a single location and lie parallel before the interlacing occurs.

Bonded fabrics : these have layered fabric structure in which a face or surface fabric is joined to a combined fabrics use as a shacking fabric.

Film fabrics : these drive from some chemicals as some of the manmade fibers , extruded in sheets instead of filaments.

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Laminated fabrics: these have a layer of fabric joined to a sheet of material, frequently polyethylene foam adds warmth and stability.

Tufted fabrics: tufting is a process of manufacturing pile fabrics by inserting loops into an already woven ground fabric.

Non woven fabrics: these are the material made of textile fibers held together by an applied bonding or adhesive agents or by the fussing of self contained thermoplastic fibers. Nonwoven fabrics are broadly defined as sheet or web structures bonded together by entangling fiber or filaments (and by perforating films) mechanically, thermally or chemically.

Different Types Of Weave For Identification Of Fabric Structure

This is a simplest form of weaving.

The weft yarn passes over one warp yarn and under the next alternately across the entire width of the fabric.

Plain weave has no wrong side unless coloured finish is applied to differentiate right or wrong side.

Attractive fabrics can be obtained by varying the number of warp yarns and filling yarns.

Most fabrics are made using plain weave. It produces strong and durable fabrics.

Plain weave:

Twill weaveThe second basic weave pattern is the twill weave. A twill weave always shows diagonal ridges across the fabric.

The twill or diagonal weave may run from left to right, or from right to left, both on the face and back of the cloth.

The simplest twill weave uses three warp yarns and three weft.

Twill weave has increased strength and warmth but more easily torn by abrasion. Examples are denim, drill, jean, someflannel and suitings.

Twill-weaves are also classified based on the yarns that form floats and wales on the right side of the fabric.

If warp floats are present or prominently seen, it is called warp-face twill-weave .

Warp-faced twill-weaves are stronger because of the higher strength and increased resistance to abrasion of warp.

Warp or weft-faced twill weave

Sateen weave This weave makes use of low-twist floating warp yarns of lustrous man-made or silk filaments.

The warp yarns pass over a number of weft yarns and under one alternately, so that the warp floats are on the surface along the length of the fabric.

The weft yarns are hardly noticeable. A variation of the satin weave in which the filling yarns float on the surface of the fabric is satin weave. Example damask, sateen,ticking and Venetian

The smooth shiny surface of a satin weave is created by the large surface area of exposed warp threads which are intermittently bound on only every fourth cross of the weft (four under, one over).

This sequence can be reversed so that the weft threads form the dominant surface area of the fabric (four over, one under) though this type of weave is called sateen.

Satin weaves are frequently used in combination with other weaves to form figured cloths. Figured cloths are woven in one colour with pattern created solely by the use of different textured weaves, for example damask.

The weave uses doubled warp and weft yarns to produce design that resembles familiar pattern of a basket.

Two or more weft yarns pass alternately over and under two or more warp yarns.

In this, two or more filling yarns with little or no twist are interlaced with a corresponding number of warp yarns; they are woven in a pattern of 2 2, 3 3 or 4 4 instead of 1 1, which is the plain weave.

In this construction the fabrics are not durable, but are more decorative. Examples are coat and suit fabrics, hopsock.

Basket weave

Ribbed-weave fabric is an unbalanced weave. Raised effect is produced along the warp or weft direction by using thicker warp or weft yarns or by allowing warp or weft to pass over a set of weft or warp yarns while interlacing. Warp-faced rib fabrics are usually termed corded weaves.

The rib appearance is made by using heavy yarns in the warp or filling direction, by grouping yarns in specific areas, or by having more number of yarns in warp than filling. Examples are poplin, broadcloth and grosgrain.

Ribbed weave

Ottoman An ottoman structure has to have a horizontal ribbed weave, a filler yarn is used to produce the raised cording effect. The structure comprises of two warps and a thick filler yarn for the cording. The second warp catches the corded rib here shown by the use of the black thread.

Corduroy A strong and hardwearing cut pile cotton cloth identifiable by its characteristically ribbed surface, the ribs may vary in width. Woven in a similar manner to velvet with the pile formed by the weft threads.

Dobby WeaveDobby designs have small figures such as dots, geometric designs and floral patterns woven into the fabric.

The design is produced by a combination of two or more basic weaves and the loom may have upto thirty two harnesses.

Examples of dobby weave are shirting madras, pique, huck towelling.

Novelty WeavesNovelty Weaves are also called as decorative, fancy, figure and design weaves. They are formed by predetermined changes in the interlacing of warp and filling yarns. The different weaves include:DobbyJacquardLenopile and double cloth.

This weave is also known as gauze or doup weave. Leno weave produces open-textured fabric that may be sheer or heavy.

In this weave the doup facilitates twisting one warp against the neighboring warp before the shed is formed, so that filling is held between such intertwined warps.

This unusual twisting of the warps like the figure of 8 holds each filling firmly in place, thereby preventing any possible weft slippage.

This increases weaves stability, strength and durability of the sheer fabrics, which are also crisp in texture.

Leno weave

Jacquard weave is the one characterized by large designs woven in intricate details.

The Major advantage of the jacquard machine is its ability to control each individual warp thread instead of threads as in harness looms.

The control over individual warp offers greater freedom for the designer in evolving large and intricate woven motifs on fabrics.

Jacquard weave

This cloth comprises of two fabrics, each with its own warp and weft, these warps can be combined together, but are more usually crossed over to produce a pattern.

The primary object is to produce a heavier cloth than could be done in a single texture, without spoiling the fineness and the weave of the face cloth.

Double cloths are reversible with the different colours alternating from the front to the back. They can also be referred to as compound cloths.

Double cloth

Extra warp or filling yarns can be interlaced on the basic weaves to produce different designs. These include:

Lappet weaveSwivel weavePile weaveSpot weaveDouble weaveSurface Figure Weaves

This weave is used to superimpose a small design on the face of the fabric as it is being woven.

Though it is referred to as a weave, the design is stitched into the fabric by needles that operate at right angles to construction. Thus the effect produced is very similar to embroidery.

The design is made with one continuous additional yarn carried on the back of the fabric from one design to the next.

The floating threads in between the designs are cut if they are long; otherwise they are left uncut, which at times may result in snagging.

Lappet weave

This weave is made with extra-filling threads. This is at times referred to as tabby, home-spun or taffeta-weave. It is the simplest to produce and consequently inexpensive; this is a weave in which each warp goes over one weft, and on return it alternates pattern of interlacing. Therefore it is called 1/1 weave; numerator indicates number of harnesses raised and denominator of lowered while shedding.

Swivel weave Separate shuttles are placed at each point where the design has to be made.

The shed is formed by the pattern, where the shuttle carries the yarn through the shed, the distance of the pattern.The extra filling floats on the back of the fabric, the long floats is cut away after weaving is completed. Example : silk sarees.

Spot designs are formed by extra warp or filling yarns. The yarns are inserted the entire length or width of the fabric, spots or dot designs are formed.

The long floats on the back side are cut away, leaving the dots.

The threads can be pulled easily. Filling threads are easy to cut but warp floats are difficult.

Example : dotted swiss.Spot Weave

Pile fabrics are formed by having the basic plain or twill weave as a backing and a third yarn is woven to yield a surface pile.

The pile may be warp pile or weft pile. For making ground fabric, plain or twill weave is used, the extra set of filling yarn floats over three or more warp yarns.

The floats are cut and brushed up to form pile. This is called filling pile.Examples are velveteen and corduroy fabrics.

If an extra warp yarn floats over the filling yarn, it is called warppile. Examples are velvet, velour and rug velvet.Pile weave

Double weave fabrics are obtained by using five or more set of yarns.

The most common types of double cloth have two set of warp and two set of weft yarns with an extra yarn interlacing both the cloth.

The double cloth has additional bulk, strength and warmth. Examples are coatings, blankets, double brocade.Double weave

Identification on The Basis of Constructional and Performance Characteristics

The fabric count is the number of warp yarns (ends) and filling yarns (picks) per inch in a woven fabric.

Pick glass with pointer was used to determine fabric count using standard test method.

It was determined by counting the number of threads per square inch in the warp and weft directions at five different places in the fabric. An average of five readings was taken.Fabric Count

The weight of fabric is defined as weight of a known area of the material and then computing the weight per unit area.

Samples were cut at random from fabric with the help of round cutter for GSM. The samples were weighed separately on the Paramount Precision Scale for GSM (grams per square meter) using standard test method.Fabric Weight (weight per unit area)

Fabric thickness is defined as the distance between two parallel surfaces while exerting a specified pressure on the material.

Thickness tester was used to determine the thickness of fabrics. A specimen was placed on flat surface below pressure foot of the instrument without any folds and wrinkles.

The pressure foot was lowered upon the specimen gently until the pointer of the dial meter stopped moving further and the reading on the dial gauge was recorded in mm.Fabric Thickness

Tensile strength is the ability of the fabric to withstand the load of force usually expresses as kilogram and percent elongation of fabric corresponding to the tensile strength is the original length of the sample at breaking point.

The sample of size 64 0.05 inches were cut out from warp and weft direction of the fabric with the help of template. The samples were mounted between the jaws with approximately 1.5 inch of fabric protruding from each side of the jaws at a distance of 3 inches .The speed of upper jaw was adjusted at 30010mm/min. The machine was started and the upper jaw moved in upward direction. The readings were taken from the digital display at sample break.Tensile Strength

Bending length is the length of fabric that will bend under its own weight to a definite extent. The bending length of the samples were determined by the paramount stiffness tester.

Samples of size 25200 mm were cut from warp and weft direction with the aid of template and conditioned.

Both template and samples were transferred to the platform with the fabric underneath, coinciding the zero mark of the scale and zero line engraved on the side of the plate form. The template was moved slowly over the 41.50 slope along with the strip till the top of the specimen viewed in the mirror cut in between both index lines. The bending length was read from the scale, which coincided with the front edge of the top plate.Bending Length

Pills are the balls or bunches of tangled fibres that are held on to the surface of a fabric by one or more fibres. Pilling resistance is the resistance to form pills on a textile fabric.This method covers the determination of resistance to the formation of pills and other related surface changes on textile fabrics.

The fabric sample measuring 5X5sq inch was sewn so as to fit firmly when placed around a rubber tube of 5 inch length, 1 inch outside and 1/8 inch thick, which was then rotated for 5 hours to complete 18,000 revolutions at the rate of 60 revolutions/min.After tumbling, the extent of pilling was assessed visually by comparing with thearbitrary standards 1,2,3,4 and 5.Rating Scale1 No pilling2 Slight pilling3 Moderate pilling4 severe pilling5 Very sever pillingPilling Test

Design is classified into two types:

Structural DesignsDecorative Designs

Structural design is a form of construction that is built into the cloth during theprocess of its manufacturing. Simplicity is a feature of structural design because the design is an integral part of its form rather than an embellishment. In textile design weaving is the most common method of producing structuraldesign. Non-woven methods like knitting, lace making can also be included in this category.

Decorative design is applied to the surface of the cloth to ornament it. The common method of producing decorative design in the field of textiles includes printing, dyeing, embroidery, appliqu and painting in addition to trimmings and certain finishing methods.

Identification of Design on Fabric

Naturalistic designs/ conversational

This depicts real objects in a natural manner. Flowers, animals, plant forms,human figure of any other object may be selected for representation certain traditional patterns. They also called novelty patterns. Examples are Animals, animal skins, cartoons, fruit, games, toys, mythological designs, vegetables, shells, sports and jungle etc.

Stylized designs/ Floral designs

These distort real objects. In this natural designs are simplified, exaggerated,rearranged or even distorted to achieve the purpose of the design. In textile industry, patterns of richly coloured, delicately petaled roses and patterns of roses sharp thorns are both referred to as floral.

The floral category includes all the gatherings of the flower garden, in fact including grasses, but agricultural produce like fruit and vegetables is considered a conversational subject. Floral motifs are more common in womens clothes and furnishing materials. Examples of floral patterns are ambi motif ,peacock motif.

Geometric Designs

geometric is to use the vocabulary of the textile industry, but it also makes them round rather like the subject of a mathematics Class.These are based on pure forms of the circle, rectangle and triangles etc. Geometric motifs include stripes, dots, checks, and plaids as well as many less usual forms. A geometric is an abstract or non-representational motif, a shape that is not a picture of something out in the real world. Examples of geometric designs are basket weave design, check board, chevron and herringbone weave, diagonal stripes, diaper pattern, ogee pattern, plaids and polka dots.

Abstract Designs

These have little or no reference to real object. Abstract implies an element of impression and a greater freedom than is found in most geometric designs. This type of design is used in modern art.

DEVELOPING PATTERNS IN TEXTILES

STRAIGHT/ block REPEAT A straight repeat can be produced by repeating your motif at measured intervals, placing each motif directly under or alongside the previous one.

BRICK REPEATA brick repeat is produced by repeating the motif at the sides as before, but moving the second row sideways as shown, like the pattern formed in for example a brick wall.

HALF DROP REPEATA half-drop is similar to a brick repeat but is produced by repeating the motif at the sides as before, but dropping the next row down.

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