CLO2601 Textiles: Fibres – Comprehensive Study Notes

PREFACE

Dr K. Pandarum welcomes students to CLO2601 “Textiles: Fibres”. The study guide is intended as a single reference, backed up by myUnisa’s activities, tutorial letters and additional multimedia. Students are urged to (1) read Tutorial Letter 101, (2) go through Learning Unit 0, and (3) take advantage of Unisa’s counselling, language, library and wellness services. Contact details for lecturer, ARCSWiD, DCCD and wellness clinics are provided. Estimated workload ≈ (120\text{ h}) for the 12-credit, NQF-level 7 module. A running portfolio must be compiled. No prescribed textbook, but Elsasser (2010) “Textiles: Concepts & Principles” is recommended.

LEARNING UNIT 0 – INTRODUCTION

Aim: enable students to select suitable textiles from yarn to colour, finish, testing and care; interpret labels; and apply correct care. Outcomes – identify fibres, state properties, make wise buying/care decisions, interpret labels, ensure service life.

LEARNING UNIT 1 – TEXTILES (pp. 1–19)

Key Concepts

• Textiles = any product made of textile fibres.
• Fibre → Yarn → Fabric → Garment.
• Textile industry components: fibre producers → yarn & fabric manufacturers → converters (dye/print/finish) → product manufacturers → retailers/consumers.

Origins & Importance

• “Textile” from Latin textere “to weave”. Over 7000 years old. Craft → factory (18th-c Industrial Revolution).
• Everyday ubiquity: clothing, protective gear, home textiles, transport, construction, medical, geo- & agrotech, sport, etc.

Fibre Classification (TFPIA)

Natural ↔ Manufactured. Natural → protein / cellulose / mineral. Manufactured → (a) cellulosic, (b) non-cellulosic, (c) mineral. Generic vs trade names e.g. polyester (generic) ↔ Trevira® (trade). Labels must show >5\% fibre content by generic name.

World & SA Industry

• 2014 fibre production: 65.2\,\text{Mt} manufactured vs 26.5\,\text{Mt} cotton. Asia ≈ 86\% of man-made output (China dominant).
• SA: historically blankets/sheets. Small internal market (≈7\,\text{kg capita}^{-1}). High variety, low volume → high cost → competition from Asian imports. Natural fibres produced: wool (merino), mohair (60 % world clip), cotton (≈40 % local demand).

LEARNING UNIT 2 – FIBRE THEORY (pp. 21–38)

Chemistry

• Fibres are polymers (macromolecules). Monomers join by addition (no by-product) or condensation (eliminate small molecule, often \mathrm{H_2O}).
• Degree of polymerisation ↑ → strength ↑.
• Fibre bulk = bundles of fibrils → fibrils → polymer chains. Amorphous vs crystalline regions. Crystalline ≡ strength; amorphous ≡ moisture uptake & deformation.

Manufactured Fibre Production

  1. Wet spinning: polymer solution extruded into coagulation bath (viscose rayon, acrylic…).

  2. Dry spinning: solvent evaporated in hot gas (acetate, triacetate…).

  3. Melt spinning: molten polymer extruded, solidifies in cool air (nylon, polyester, PP).

  4. Gel spinning: semi-liquid jet → air → bath (high-strength aramid/PE).

Drawing aligns molecules → strength. Spinneret hole shape controls cross-section; terms: monofilament, multifilament, staple, tow, textured.

Fibre Modifications

Microdenier (<1\,\text{den}), non-round, thick & thin, hollow, bicomponent, high-tenacity, low-pilling, additives (delustre, antistatic, FR, UV).

Nanofibres

Diameter <500\,\mathrm{nm}. Produced via split-bicomponent (islands-in-sea) or electrospinning. Apps: medical, filtration, energy.

Identification

Burn test, microscopy, solubility, melting point. Characteristic flame/odour/ash for each fibre family.

LEARNING UNIT 3 – FIBRE PROPERTIES (pp. 39–63)

Physical Structure

Length, diameter (denier/tex), cross-section, surface contour, crimp.

Primary Properties (must-have)

  1. Length-to-width >100. 2 Strength (tenacity \mathrm{cN/tex}). 3 Flexibility. 4 Spinning cohesiveness. 5 Uniformity.

Secondary (Performance)

Density, lustre, colour, abrasion, pilling, elasticity, moisture absorption, heat conduction, resiliency, dimensional stability, thermal & chemical resistance, cost.

Serviceability Domains

Aesthetics, durability, comfort, appearance retention, care. Table correlates fibre structure ⇄ serviceability.

LEARNING UNIT 4 – NATURAL PROTEIN FIBRES (pp. 64–88)

Wool

• From sheep (merino premium).
• Surface = overlapping scales; length 12–381\,\text{mm}; diameter 10–60\,\mu m; natural crimp.
• Serviceability: hygroscopic (13–18\%), warm (low conductivity), excellent resiliency/elasticity, prone to felting shrinkage & moths, weak alkali resistance.
• End uses: apparel, carpet.

Silk

• Bombyx mori filament (upto 1500\,\text{m}). Triangular cross-section; smooth; high lustre.
• Serviceability: strong (31–44\,\text{cN/tex}), hygroscopic (11\%), warm but can weave sheer, medium resiliency, weak in sunlight & perspiration.

Speciality fibres

Mohair (angora goat), cashmere (Kashmir goat), camel, alpaca, vicuña, qiviut, angora rabbit. Properties: light, soft, lustrous, warm, expensive; mainly luxury apparel/blends.

LEARNING UNIT 5 – NATURAL CELLULOSE FIBRES (pp. 89–109)

Cotton (seed)

• Kidney-shaped collapsed tube; lumen; twist (convolution). Length 12–63\,\text{mm}; dia 12–25\,\mu m.
• Serviceability: absorbent (7\%), cool, moderate strength (stronger wet), low resiliency/elasticity, easy care, susceptible to mildew/sun.

Flax (bast → linen)

• Long bundles 25–40\,\text{mm} with nodes; polygonal cross-section.
• Very strong (wet > dry), highly absorbent (12\%), cool, crisp hand, poor resiliency, stiff.

Other Plant Fibres

Jute, ramie, hemp (bast); sisal, abaca, pina (leaf); coir, kapok (seed). Mostly industrial/specialty.

LEARNING UNIT 6 – MANUFACTURED CELLULOSICS (pp. 110–122)

Rayon (viscose)

Wood/cotton pulp dissolved (NaOH+CS$_2$) → wet-spun. Soft, absorbent (12–14\%), drapes, weak (wet\downarrow50\%), low resiliency.

Lyocell

Solvent-spun cellulose (N-MMO). Stronger than rayon, fibrillates for peachskin; eco-friendly.

Acetate / Triacetate

Cellulose esterified with acetic acid; dry-spun. Thermoplastic, lustrous, poor strength, low absorbency, dry-clean, melts easily.

LEARNING UNIT 7 – POLYAMIDES (pp. 123–132)

Nylon 6 / 6.6

Condensation of diamine + diacid; melt-spun. Strong (31–45\,\text{cN/tex}), excellent abrasion, light, low absorbency (3.5–5\%), high resiliency, thermoplastic. Uses: hosiery, carpets, ropes, apparel blends.

Aramids

Nomex® (FR, >370^{\circ}\text{C}), Kevlar® (tenacity \sim194\,\text{cN/tex}). Protective gear, ballistic, heat-resistant.

LEARNING UNIT 8 – POLYESTER (pp. 133–142)

PET from terephthalic acid+MEG; melt-spun. Very strong, excellent resiliency, low moisture 0.4–0.5\%, thermoplastic, oleophilic. Microfibres & blends (e.g. 65/35 poly-cotton) dominate market (>54\% global share).

LEARNING UNIT 9 – ACRYLIC & MODACRYLIC (pp. 143–152)

Addition polymer of acrylonitrile; wet/dry-spun staple. Wool-like, soft, warm, low density, sunlight-resistant, moderate strength, pills, low absorbency. Modacrylic (35–85% AN) self-extinguishing: wigs, fake fur, FR fabrics.

LEARNING UNIT 10 – POLYOLEFINS (pp. 153–156)

Polyethylene (PE) & polypropylene (PP). Melt-spun, hydrophobic, low density. PE high-strength Spectra® via gel-spinning. PP good wicking, carpets, thermal underwear.

LEARNING UNIT 11 – ELASTOMERIC (pp. 157–160)

Natural rubber: high stretch but heat/oil sensitive. Spandex (Lycra®): 500–700\% elongation, excellent recovery, chlorine-sensitive, used in stretch apparel. Lastol®, elasterell-P = olefin/polyester elastic fibres.

LEARNING UNIT 12 – MINERAL & METALLIC (pp. 161–166)

Asbestos: non-flammable but carcinogenic. Glass fibre: silicate, heat & chemical-resistant, non-absorbent; used in insulation, filters. Metallic fibres (Al, Au, Ag) for decorative yarns, antistatic carpets. Stainless steel & carbon fibres for tech uses.

LEARNING UNIT 13 – GREEN FIBRES (pp. 167–179)

Organic wool/cotton (no synthetic chemicals). Naturally coloured cotton (brown, green). Fibres from agricultural waste: pineapple, banana, agave. Manufactured “eco” fibres: Lyocell (Tencel®), PLA (corn-based), bamboo (viscose/ mechanically extracted), soybean protein. Emphasis on renewability, biodegradability and low-toxic processing.

LEARNING UNIT 14 – LABELLING & CARE (pp. 180–189)

TFPIA requires >5\% fibre disclosure by generic name; SA Merchandise Marks Act enforces country-of-origin and care. Blends used to balance properties/cost. Eco-labels (Oeko-Tex, EU-Flower, Nordic Swan) certify low environmental impact. Care symbols: wash tub (temp/hand), triangle (bleach), iron (dots), circle (dry clean solvent), square (drying). Example tables supplied.

LEARNING UNIT 15 – CHOICE FOR USE (pp. 191–197)

Methodology: 1 analyse end-use → list required serviceability properties; 2 match with fibre properties; 3 select one/two fibres and justify (advantages vs disadvantages incl. cost). Portfolio activities reinforce selection/evaluation skills.

KEY EQUATIONS & UNITS

• Tenacity = \frac{\text{Force (g)}}{\text{Denier}} \;\;\text{or}\;\; \mathrm{cN/tex}
• Density \rho\,(\text{g/cm}^3); Water =1.

PRACTICAL IMPLICATIONS

• Burn, microscopy & solubility tests essential for fibre ID.
• Fibre blending (e.g. 65/35 poly-cotton) marries durability with comfort.
• Care labels guide washing/ironing; thermoplastics (nylon, PET) require <180^{\circ}\text{C}.
• Eco-concerns drive organic, recycled & bio-derived fibres (Lyocell, PLA).

ETHICAL & SUSTAINABILITY NOTES

• Asbestos banned due to health risk.
• Organic certification improves worker/environment welfare.
• Recycled PET and PLA reduce fossil dependence.
• Animal welfare issues in wool/mohair; use RWS or organic standards.

PORTFOLIO TIPS

Compile: (a) fibre samples with burn-test notes; (b) care-label collection; (c) analyses of garments vs fibre properties; (d) mind-maps of serviceability relationships. Use these as exam revision.