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MSCE Clothing and Textiles study materials
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MSCE Clothing and Textiles practice questions

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Question 1Fibres, Yarns and Fabric Construction

Which natural fibre is obtained from the seed hair of a plant and is composed mainly of cellulose?

  1. Cotton Correct answer.
  2. Wool
  3. Silk
  4. Flax

Explanation

Cotton fibres develop as single-celled seed hairs in the boll of the cotton plant and consist of roughly 90 percent cellulose, making them the classic seed fibre. Wool and silk are animal proteins, and flax is a bast fibre from the stem.

Question 2Fibres, Yarns and Fabric Construction

Which term describes the natural crimp and bulk that wool fibres develop when they are mechanically agitated in warm, moist conditions?

  1. Mercerisation
  2. Singeing
  3. Calendering
  4. Felting Correct answer.

Explanation

Felting occurs because wool scales allow fibres to migrate and interlock irreversibly under moisture, heat and friction. Mercerisation, singeing and calendering are all finishing treatments applied to fabric rather than a property of wool under agitation.

Question 3Fibres, Yarns and Fabric Construction

A yarn is described as having a high twist multiplier. What effect does this generally have on the yarn?

  1. Improved lustre with no change in strength
  2. Lower tensile strength with increased diameter
  3. Greater bulk and softer handle
  4. Higher strength with reduced absorbency and a harsher hand Correct answer.

Explanation

Increasing twist binds fibres more tightly, which raises tensile strength up to an optimum point but compacts the yarn, reducing porosity and absorbency and giving a harder hand. Excess twist beyond the optimum actually lowers strength and causes snarling.

Question 4Fibres, Yarns and Fabric Construction

Which weave structure produces the smoothest, most lustrous surface because the warp or weft floats cover much of the fabric?

  1. Plain weave
  2. Twill weave
  3. Basket weave
  4. Satin weave Correct answer.

Explanation

Satin weave uses long floats that pass over several yarns before interlacing, so the surface is dominated by float yarns and reflects light strongly. Plain and basket weaves interlace frequently, and twill shows a diagonal rib rather than a smooth float face.

Question 5Fibres, Yarns and Fabric Construction

Which fibre is a regenerated cellulosic filament produced by dissolving wood pulp and extruding it through spinnerets?

  1. Viscose rayon Correct answer.
  2. Nylon
  3. Polyester
  4. Acrylic

Explanation

Viscose rayon is made by converting cellulose from wood pulp into a soluble xanthate, then extruding the solution into an acid bath where it regenerates as filament. Polyester, nylon and acrylic are all fully synthetic polymers derived from petrochemicals.

Question 6Fibres, Yarns and Fabric Construction

In staple spinning, what is the purpose of the carding operation?

  1. To dye the fibre before blending
  2. To twist the yarn to its final count
  3. To align fibres parallel and remove short fibres and trash Correct answer.
  4. To set the twist permanently in the yarn

Explanation

Carding opens the fibre mass, individualises fibres, removes neps and impurities, and forms a carded sliver with partial alignment. Combing is the later process that removes short fibres and improves parallelisation further.

Question 7Fibres, Yarns and Fabric Construction

Which property makes polyester popular for easy-care apparel?

  1. High moisture regain
  2. Thermoplastic behaviour allowing heat-set creases Correct answer.
  3. Low elastic recovery
  4. Susceptibility to mildew

Explanation

Polyester is thermoplastic, so fabrics can be heat-set into durable pleats and creases and recover from wrinkling in wear and washing. Its low moisture regain and resistance to mildew are additional easy-care advantages, not drawbacks.

Question 8Fibres, Yarns and Fabric Construction

A single yarn made by twisting together two or more already-spun single yarns is called what?

  1. Roving
  2. Slub
  3. Rotor yarn
  4. Folded yarn Correct answer.

Explanation

A folded, or plied, yarn is produced by twisting two or more single yarns together to improve strength, evenness and balance. Roving is an intermediate spinning stage, a slub is a deliberate thick place, and rotor yarn is an open-end spun single yarn.

Question 9Fibres, Yarns and Fabric Construction

Why does cotton fabric shrink after its first laundering?

  1. Because the fabric gains moisture regain permanently
  2. Because the fibres melt and contract
  3. Because the dye leaches out of the fabric
  4. Because tension imposed during spinning and weaving is released and fibres swell Correct answer.

Explanation

Cotton fibres are held under tension during yarn and fabric manufacture; when wetted, they swell and the built-in strain relaxes, so the fabric contracts. This is why cotton goods are usually sanforised or pre-shrunk before sale.

Question 10Fibres, Yarns and Fabric Construction

A manufacturer wants a lightweight fabric with good drape and a soft hand for a blouse. Which construction would best meet this requirement?

  1. A heavy double-cloth in twill weave
  2. A fine filament chiffon in plain weave with low twist Correct answer.
  3. A tightly woven heavy canvas in plain weave
  4. A coarse burlap in basket weave

Explanation

Fine filament yarns with low twist produce a light, flexible fabric that drapes softly and feels smooth. Heavy canvases, coarse burlap and double cloths are thick and stiff, which is the opposite of the requirement.

Question 11Fibres, Yarns and Fabric Construction

What is the main advantage of combing cotton or wool before spinning?

  1. It increases the fibre diameter
  2. It removes short fibres and aligns the long fibres for a smoother, stronger yarn Correct answer.
  3. It makes the fibre water-repellent
  4. It adds twist to the yarn

Explanation

Combing removes short fibres and neps and lays the remaining long fibres parallel, so the resulting yarn is smoother, stronger and more lustrous. Carded yarns retain short fibres and are bulkier but less even.

Question 12Fibres, Yarns and Fabric Construction

Which yarn fault would most likely cause a thin, weak place and a visible fault line across a woven fabric?

  1. A nep
  2. A missing pick
  3. A slub
  4. A thin place caused by insufficient fibres in the drafting zone Correct answer.

Explanation

Insufficient fibres in the drafting zone produce a thin place with fewer fibres carrying the load, so the yarn is weak there and shows as a fault. Slubs and neps are thick places, and a missing pick is a weft interruption rather than a yarn drafting fault.

Question 13Fibres, Yarns and Fabric Construction

In a twill weave, what determines the direction of the diagonal line on the fabric face?

  1. The finishing temperature of the fabric
  2. The direction of the warp and weft interlacing progression Correct answer.
  3. The colour of the weft yarn only
  4. The amount of size applied to the warp

Explanation

Twill lines arise because each successive weft pick advances the interlacing point by one or more ends, creating a stepped diagonal. The direction of that progression, together with whether warp or weft floats dominate, sets the diagonal direction.

Question 14Fibres, Yarns and Fabric Construction

Which fibre blend is commonly used to combine the moisture absorbency of a natural fibre with the strength and quick drying of a synthetic?

  1. Cotton and polyester Correct answer.
  2. Viscose and acetate
  3. Wool and silk
  4. Nylon and polyester

Explanation

Polyester-cotton blends pair cotton's absorbency and comfort with polyester's strength, abrasion resistance and rapid drying, which is why they dominate shirting and workwear. The other pairs do not combine a natural absorbent fibre with a strong synthetic in the same way.

Question 15Fibres, Yarns and Fabric Construction

A knitted fabric stretches more than a woven fabric of similar mass mainly because of what?

  1. Interlooped yarns that allow loops to deform under tension Correct answer.
  2. Greater fibre length in the yarn
  3. Higher twist in the yarns
  4. Longer floats in the structure

Explanation

Knit structures are built from interlocking loops, so applied tension straightens and reorients the loops, giving high extensibility. Woven fabrics rely on straight interlaced yarns that resist extension until the crimp is pulled out.

Question 16Fibres, Yarns and Fabric Construction

Which characteristic distinguishes filament yarns from staple yarns?

  1. Filament yarns always contain short fibres
  2. Filament yarns are made from continuous fibres of indefinite length Correct answer.
  3. Filament yarns are only produced from natural fibres
  4. Filament yarns cannot be textured

Explanation

Filament yarns consist of continuous strands, either natural silk or extruded synthetic filaments, so they have no fibre ends protruding and appear smooth and lustrous. Staple yarns are spun from short fibres and need twist to hold them together.

Question 17Fibres, Yarns and Fabric Construction

Why is sized warp yarn used on a loom?

  1. To coat the yarn and reduce abrasion and breakage during weaving Correct answer.
  2. To lower the tensile strength of the warp
  3. To increase the crimp of the weft
  4. To add colour to the finished fabric

Explanation

Warp yarns endure repeated abrasion and tension from healds and reed during weaving, so a size film is applied to protect them and reduce breakage. Size is later removed in desizing before dyeing and finishing.

Question 18Fibres, Yarns and Fabric Construction

A fabric label states the garment is made from 100 percent acrylic. Which property set is most consistent with this fibre?

  1. High moisture regain and low warmth
  2. High density and poor colour retention
  3. Warm, light, quick drying and resistant to moths Correct answer.
  4. Strong alkali resistance and high heat resistance

Explanation

Acrylic is a lightweight, warm synthetic often used as a wool substitute; it dries quickly, holds colour well and resists moths and mildew. It has low moisture regain and moderate heat sensitivity, so the other options contradict its known behaviour.

Question 19Fibres, Yarns and Fabric Construction

Which weave would you select to produce a durable, closely woven fabric with a fine diagonal rib for workwear?

  1. Leno weave
  2. Twill weave Correct answer.
  3. Satin weave
  4. Pile weave

Explanation

Twill weave gives a compact, abrasion-resistant fabric with a characteristic diagonal rib, which is why it is common in denim and workwear. Satin is smooth but float-prone, leno is an open gauze structure, and pile weave produces a raised surface.

Question 20Fibres, Yarns and Fabric Construction

Which statement best explains why viscose rayon has lower wet strength than dry strength?

  1. Water removes the fibre's orientation
  2. Water increases the crystallinity of the fibre
  3. Water plasticises the amorphous regions and disrupts hydrogen bonding between chains Correct answer.
  4. Water adds cross-links between cellulose chains

Explanation

Water penetrates the less ordered amorphous regions, breaking intermolecular hydrogen bonds and allowing chains to slide more easily, so the fibre loses strength when wet. Viscose has a high amorphous content, which makes this loss pronounced.

Question 21Fibres, Yarns and Fabric Construction

A spinner produces a yarn with excessive twist that snarls when relaxed. What is the most appropriate correction?

  1. Use shorter fibres in the blend
  2. Reduce the twist per unit length to suit the yarn count Correct answer.
  3. Increase the yarn count without adjusting twist
  4. Increase the spindle speed further

Explanation

Snarling indicates that twist is above the level the yarn can sustain, so the twist multiplier should be reduced relative to the yarn count. Twist must always be matched to count and end use to avoid liveliness and snarling.

Question 22Fibres, Yarns and Fabric Construction

Why does a satin-weave fabric show poorer abrasion resistance than a plain-weave fabric of the same fibre?

  1. Plain weave has more crimp and therefore less strength
  2. Satin weave uses weaker fibres
  3. Long floats stand proud of the surface and are easily snagged and worn Correct answer.
  4. Satin weave cannot be made from staple yarns

Explanation

In satin weave, long floats cover the surface and bear the abrasion directly, so they snag and break relatively easily. Plain weave distributes interlacing points evenly, giving better resistance to surface wear.

Question 23Fibres, Yarns and Fabric Construction

During spinning, a mill observes periodic thick and thin places at regular intervals along the yarn. Which cause is most likely?

  1. Random fibre variation in the raw cotton
  2. Over-lubrication of the ring traveller
  3. A defective drafting roller with an eccentric or damaged surface Correct answer.
  4. Insufficient twist in the yarn

Explanation

Faults that repeat at regular intervals point to a mechanical cause, such as a damaged or eccentric drafting roller producing a periodic drafting wave. Random fibre variation gives irregular but non-periodic thickness changes.

Question 24Fibres, Yarns and Fabric Construction

Which combination of fibre and structure would best give a fabric that insulates in cold, wet conditions while retaining shape?

  1. Wool in a compact rib knit Correct answer.
  2. Acetate in a plain-weave voile
  3. Viscose in an open leno weave
  4. Cotton jersey in a single knit

Explanation

Wool provides warmth even when damp because its crimp traps air and its regain is high, and a compact rib knit adds thickness and elastic recovery for shape retention. Cotton jersey is thin and stays wet, while open leno and voile give little insulation.

Question 25Fibres, Yarns and Fabric Construction

A fabric made from filament yarns shows a glossy appearance, while the same polymer in staple form appears matt. What is the primary reason?

  1. Staple fibres have more protruding fibre ends that scatter light Correct answer.
  2. Staple fibres are always dyed a darker shade
  3. Filament yarns contain more pigment
  4. Filament yarns have lower orientation

Explanation

Continuous filament yarns present an aligned, smooth surface that reflects light directionally and appears lustrous. Staple yarns have many fibre ends and a slightly hairy surface that scatters light, so the fabric looks matt.

Question 26Fibres, Yarns and Fabric Construction

Which spinning method produces a yarn by wrapping fibres around a continuous core filament rather than by inserting twist into a drafted staple strand?

  1. Worsted ring spinning
  2. Wrap spinning Correct answer.
  3. Rotor open-end spinning
  4. Ring spinning

Explanation

Wrap spinning (including air-jet and self-twist variants) forms a sheath of fibres wrapped around a core filament or staple bundle, so cohesion comes from the wrapping rather than from true twist inserted into the whole strand. Ring, rotor and worsted ring spinning all rely on twist inserted into a drafted staple fibre assembly.

Question 27Fibres, Yarns and Fabric Construction

A weaver needs a fabric with a smooth, lustrous face and a high sett, where long floats of warp yarn pass over many weft picks. Which weave structure fits this specification?

  1. Basket weave
  2. 2/2 matt weave
  3. Warp-faced satin Correct answer.
  4. Plain weave

Explanation

Satin weaves use long floats of one yarn system over several of the other, and when the warp floats dominate the face the result is a warp-faced satin with a smooth, lustrous surface. Plain, matt and basket weaves all interlace frequently, giving a flatter, less reflective surface.

Question 28Fibres, Yarns and Fabric Construction

A yarn is described as having a metric count (Nm) of 40. What does this value indicate about the yarn?

  1. 1 kilogram of yarn measures 40 metres
  2. 40 metres of yarn weigh 1 gram
  3. 1 gram of yarn measures 40 kilometres
  4. 40 kilometres of yarn weigh 1 kilogram Correct answer.

Explanation

Metric count is an indirect system: Nm 40 means 40 000 metres (40 km) of yarn weigh 1 kilogram, or 40 metres per gram. The higher the Nm, the finer the yarn, which is the opposite of direct systems such as tex.

Question 29Fibres, Yarns and Fabric Construction

A plain-weave cotton poplin and a plain-weave cotton voile are woven from similar yarns, but the poplin has roughly twice the sett in both directions. Which outcome is expected when both are tested for cover factor and air permeability?

  1. The poplin has a higher cover factor and lower air permeability Correct answer.
  2. The poplin has a higher cover factor and higher air permeability
  3. The voile has a higher cover factor and lower air permeability
  4. Both fabrics have equal cover factor because the weave is identical

Explanation

Cover factor rises with the number of yarns per unit width for a given yarn count, so the denser poplin covers more of the fabric area. Greater coverage blocks more of the open spaces between yarns, so air permeability falls as sett increases. Weave alone does not fix cover factor; yarn spacing does.

Question 30Fibres, Yarns and Fabric Construction

A converter blends 65 percent polyester staple with 35 percent combed cotton and spins the blend into a yarn for shirting. Which statement best explains why the fibres are blended before rather than after spinning?

  1. Blending before spinning lets each fibre contribute its property along the whole yarn length, so no single fibre type forms discrete bands Correct answer.
  2. Blending before spinning converts the polyester staple into filament so it can wrap the cotton
  3. Blending before spinning increases the average fibre length above that of the cotton component
  4. Blending before spinning removes the need for drawing and doubling in the preparation sequence

Explanation

Intimate blending at the fibre stage distributes both components throughout the yarn cross-section and length, so strength, moisture uptake and abrasion resistance are averaged rather than localised. Blending after spinning would give stripes or blocks of each fibre, and the properties would not combine at the point of wear.

Question 31Textile Science, Finishes and Care

Which natural fibre is composed mainly of the protein keratin and therefore burns with the smell of burnt hair?

  1. Cotton
  2. Flax
  3. Viscose rayon
  4. Wool Correct answer.

Explanation

Wool is an animal fibre built from keratin protein, and its nitrogen and sulfur content produces a characteristic burnt-hair odour when ignited. Cellulosic fibres such as cotton, flax and viscose smell of burning paper instead.

Question 32Textile Science, Finishes and Care

A care label shows a tub symbol with one horizontal bar beneath it. What does this indicate?

  1. Machine wash on a gentle or mild cycle Correct answer.
  2. Do not wash in water
  3. Machine wash in hot water
  4. Hand wash only

Explanation

In the international care labelling system a single bar under the washtub signals a mild or gentle machine cycle with reduced agitation. Additional bars indicate even gentler treatment, and a hand in the tub is the separate hand-wash symbol.

Question 33Textile Science, Finishes and Care

Which weave structure produces the smoothest, most lustrous fabric surface from continuous-filament yarns because interlacing points are minimised?

  1. Pile weave
  2. Plain weave
  3. Twill weave
  4. Satin weave Correct answer.

Explanation

Satin weave floats the warp or weft yarn over several opposing yarns before interlacing, so the surface is dominated by long floats that reflect light and feel smooth. Plain and twill weaves interlace far more frequently and appear more matte.

Question 34Textile Science, Finishes and Care

Why is cotton fabric normally treated with a mercerising solution of sodium hydroxide under tension?

  1. To make the fabric flame retardant
  2. To impart permanent creases
  3. To increase lustre, strength and dye uptake Correct answer.
  4. To reduce the fibre's moisture regain

Explanation

Mercerisation swells the cotton fibre under tension, reorganising the cellulose so the fibre becomes rounder and more lustrous while tensile strength and dye affinity rise. It does not add flame retardancy, set creases or lower moisture absorption.

Question 35Textile Science, Finishes and Care

Which fibre is classified as a regenerated cellulosic manufactured fibre?

  1. Acrylic
  2. Nylon 6,6
  3. Acetate Correct answer.
  4. Polyester

Explanation

Acetate is made by acetylating cellulose from wood pulp and spinning it into filaments, so it is a regenerated cellulosic fibre. Polyester, nylon and acrylic are fully synthetic polymers derived from petrochemicals.

Question 36Textile Science, Finishes and Care

What is the main purpose of a sanforising finish on cotton woven fabric?

  1. To increase the fabric's flammability
  2. To give the fabric a permanent glaze
  3. To reduce residual shrinkage in the finished garment Correct answer.
  4. To shrink the fabric deliberately before cutting

Explanation

Sanforising compacts the fabric mechanically between a rubber belt and a heated cylinder so that most of the potential shrinkage is removed before garment manufacture. This keeps the finished article close to its labelled size after washing.

Question 37Textile Science, Finishes and Care

Which laundry practice best protects a dark-coloured cotton knit from premature colour loss?

  1. Soaking overnight in an alkaline detergent solution
  2. Turning the garment inside out and washing at a cool temperature Correct answer.
  3. Drying in direct summer sunlight
  4. Washing in very hot water with a strong bleach

Explanation

Dark dyes are lost through abrasion, heat and light, so turning the garment inside out reduces surface rubbing and cool water slows dye desorption. Direct sun and hot alkaline soaking both accelerate fading.

Question 38Textile Science, Finishes and Care

A consumer washes a wool jumper in hot water with vigorous agitation and it emerges much smaller and denser. Which mechanism explains this?

  1. Relaxation shrinkage of the yarn crimp
  2. Thermal shrinkage of the polymer chains
  3. Loss of sizing from the yarns
  4. Felting caused by differential friction between scales Correct answer.

Explanation

Wool fibres have surface scales that allow them to ratchet in one direction under agitation and moisture, so the fibres migrate and entangle into a denser felted mass. The result is irreversible shrinkage and a stiff, matted handle.

Question 39Textile Science, Finishes and Care

Why is a resin durable-press finish on cotton often accompanied by a loss in tear strength?

  1. The resin dissolves part of the cellulose polymer
  2. The resin coats the yarn surface and adds weight
  3. The finish removes moisture from the fibre permanently
  4. Cross-linking restricts fibre movement and embrittles the cellulose Correct answer.

Explanation

Durable-press resins cross-link cellulose chains within the fibre, which locks the structure and prevents the slippage that normally distributes stress. The stiffened, less extensible fibre concentrates stress at flaws, so tear and abrasion resistance fall.

Question 40Textile Science, Finishes and Care

Which test method would you choose to determine the colourfastness of a dyed fabric to repeated domestic laundering?

  1. A bursting strength test
  2. An accelerated laundering test with a multi-fibre adjacent strip Correct answer.
  3. A Martindale abrasion test
  4. A vertical flammability test

Explanation

Colourfastness to washing is assessed by laundering the specimen under controlled temperature, detergent and mechanical action alongside a multi-fibre strip. Any staining of the adjacent fibres and any change in the specimen's shade are then graded against standard grey scales.

Question 41Textile Science, Finishes and Care

A garment labelled 'dry clean only' is made from a fabric that shrinks and loses body when washed. Which fibre blend most plausibly explains this behaviour?

  1. Mercerised cotton with elastane
  2. Polypropylene with nylon
  3. Solution-dyed polyester with cotton
  4. Wool with viscose rayon Correct answer.

Explanation

Wool felts and viscose rayon loses strength and shrinks markedly in water, especially with agitation, so the blend is poorly suited to home laundering. Dry cleaning with a solvent avoids both mechanisms.

Question 42Textile Science, Finishes and Care

What is the principal function of a fluorochemical soil-release finish on a polyester workwear fabric?

  1. To cross-link the polyester chains for crease recovery
  2. To lower surface energy so oily soils are repelled and wash out readily Correct answer.
  3. To provide a conductive path for static dissipation
  4. To increase the fabric's moisture regain to cotton levels

Explanation

Fluorochemical finishes create a low-energy surface that resists wetting by oils and water, so soils sit on the surface and are released during laundering. They do not modify the polymer's moisture regain or cross-link polyester.

Question 43Textile Science, Finishes and Care

A plain-weave cotton fabric and a twill-weave cotton fabric of identical mass per unit area are compared. Which statement about their properties is most accurate?

  1. The two will be identical because mass per unit area is the same
  2. The twill will have more interlacing points and greater stiffness
  3. The twill will generally drape more softly and have lower strength
  4. The plain weave will generally be firmer and more dimensionally stable Correct answer.

Explanation

Plain weave has the maximum number of interlacing points, which makes the fabric firm, stable and resistant to distortion. Twill's longer floats give it greater drape, softness and diagonal rib, so identical mass does not mean identical behaviour.

Question 44Textile Science, Finishes and Care

Which condition most strongly promotes the growth of mildew on a stored cotton canvas tent?

  1. Storage in a dry, ventilated cupboard
  2. Packing the tent away damp in a warm, dark bag Correct answer.
  3. Folding the tent along its original creases
  4. Exposure to bright sunlight before packing

Explanation

Mildew requires moisture, warmth and organic nutrients, all of which are present when damp cotton is sealed in a dark bag. Cellulose provides the food source, so the fungus stains and weakens the fabric.

Question 45Textile Science, Finishes and Care

Why does acetate fabric tend to retain heat-set creases and pleats so effectively?

  1. The polymer is thermoplastic and softens enough to be moulded by heat Correct answer.
  2. The fabric is coated with a permanent resin
  3. The fibre absorbs large amounts of water that lock the shape
  4. The fibre has a highly crystalline structure that resists deformation

Explanation

Acetate is a thermoplastic fibre, so steam and heat soften the polymer and allow it to be shaped; cooling then fixes the new configuration. This is why pleats and creases set into acetate garments with moist heat.

Question 46Textile Science, Finishes and Care

A care label advises 'do not wring or tumble dry' for a viscose rayon garment. Which property of the fibre best justifies this instruction?

  1. High resistance to alkalis
  2. High elastic recovery in the wet state
  3. Low wet strength and easy distortion when wet Correct answer.
  4. High thermoplasticity at low temperature

Explanation

Viscose rayon loses a large proportion of its strength when wet and deforms readily under mechanical stress, so wringing can stretch or tear it. Tumble drying adds heat and tumbling action that can further distort the garment.

Question 47Textile Science, Finishes and Care

Which finish would you specify to give a cotton/polyester uniform fabric durable antistatic performance?

  1. A hydrophilic antistatic agent that conducts charge away Correct answer.
  2. A fluorochemical stain repellent
  3. A silicone softener applied heavily
  4. A wax emulsion applied at the surface

Explanation

Antistatic finishes work by making the surface slightly conductive, either through hydrophilic groups that attract moisture or through ionic species that dissipate charge. A durable finish must remain effective after repeated washing.

Question 48Textile Science, Finishes and Care

Why is a flame-retardant finish on cotton often based on phosphorus and nitrogen chemistry?

  1. These elements act purely as lubricants between fibres
  2. These elements promote char formation and suppress flammable volatiles Correct answer.
  3. These elements raise the fibre's melting point above 300 degrees Celsius
  4. These elements increase the oxygen content of the fibre

Explanation

Phosphorus-nitrogen systems catalyse dehydration of cellulose during pyrolysis, favouring a carbonaceous char and limiting the formation of flammable tarry volatiles. This interrupts the combustion cycle and reduces heat release.

Question 49Textile Science, Finishes and Care

A dyer observes that a reactive-dyed cotton fabric shows poor wash fastness. Which explanation is most consistent with reactive dye chemistry?

  1. The fibre had been mercerised before dyeing
  2. The dye bath was too acidic for the fibre
  3. Unfixed hydrolysed dye remained on the fibre and bled during washing Correct answer.
  4. The dye was fully covalently bonded and excess dye was removed

Explanation

Reactive dyes that fail to react with cellulose hydrolyse to a form that cannot bond and stays loosely on the fibre. Unless this unfixed dye is thoroughly soaped off, it bleeds in washing and lowers fastness even though the bonded dye is permanent.

Question 50Textile Science, Finishes and Care

A fabric is described as having a 'crease recovery angle' of 300 degrees after a durable-press finish. What does this measurement indicate?

  1. The rate at which the fabric absorbs water
  2. The force needed to tear the fabric
  3. The angle to which the fabric returns after being folded and released Correct answer.
  4. The temperature at which the fabric begins to char

Explanation

Crease recovery is measured by folding a specimen under a known load, releasing it and measuring the angle to which it springs back. A larger recovery angle indicates better resistance to wrinkling.