Fashion Designer Textile Science & Fiber Properties 2 — Questions and Answers
Question 1: What is the difference between 'woven' and 'knit' fabric structures and how does this affect garment construction?
- Woven fabrics are made of natural fibers; knit fabrics of synthetic fibers
- Woven fabrics have minimal stretch and stable dimensions; knit fabrics are formed by interlocking loops that create inherent stretch, requiring different construction techniques (Correct answer)
- Woven fabrics are lighter than knit fabrics of the same fiber
- Knit fabrics require more seam allowance than woven fabrics
Correct answer: Woven fabrics have minimal stretch and stable dimensions; knit fabrics are formed by interlocking loops that create inherent stretch, requiring different construction techniques
The interlocked loop structure of knit fabrics creates inherent stretch in multiple directions, requiring construction adaptations: stretch stitches, appropriate needle types, different ease allowances, and often serging/overlocking rather than straight seaming.
Woven fabric construction stability means patterns have firm grain lines, standard seam allowances (5/8 inch), and hold their shape without stretch-resistant stitching. Knit patterns typically include less ease (the stretch compensates), use stretch or zigzag stitching, and often finish seams with an overlocker/serger. Knit fabrics also require ballpoint needles to avoid snagging the loops.
Question 2: What is 'mercerization' and what effect does it have on cotton fabric?
- A type of cotton weave that creates a matte surface
- A chemical treatment using sodium hydroxide that permanently swells cotton fibers, increasing luster, strength, dye affinity, and dimensional stability (Correct answer)
- A natural aging process that softens cotton over time
- A washing technique that prevents cotton from shrinking
Correct answer: A chemical treatment using sodium hydroxide that permanently swells cotton fibers, increasing luster, strength, dye affinity, and dimensional stability
Mercerization (developed by John Mercer, 1844) treats cotton with caustic soda under tension, permanently altering fiber cross-section to round (from flat), increasing luster, tensile strength, dye depth, and reducing shrinkage tendency.
Unmercerized cotton fibers have an irregular, ribbon-like cross-section that scatters light, giving a matte appearance. Mercerization rounds the cross-section, creating more even light reflection and a silk-like luster. The process also increases dye affinity (requiring less dye for equivalent depth), improves strength, and increases the fabric's stability against shrinkage. Mercerized cotton is used in fine shirting, knitwear, and embroidery thread where luster and performance are important.
Question 3: What is 'modal' fiber and how does it differ from standard viscose rayon?
- Modal is a synthetic petroleum-based fiber while viscose is natural
- Modal is a higher-generation regenerated cellulosic fiber made from beech tree pulp that is stronger, softer, and more dimensionally stable when wet than standard viscose (Correct answer)
- Modal is a trade name for polyester microfiber
- Modal and viscose rayon are identical products with different marketing names
Correct answer: Modal is a higher-generation regenerated cellulosic fiber made from beech tree pulp that is stronger, softer, and more dimensionally stable when wet than standard viscose
Modal (developed by Lenzing AG) is a second-generation viscose made specifically from beech tree pulp with a modified spinning process that produces fibers with superior wet strength, softness, and dimensional stability compared to standard viscose.
Standard viscose rayon loses significant strength when wet, making it prone to distortion and requiring careful laundering. Modal's modified spinning process creates a more crystalline fiber structure that retains much more of its dry strength when wet, approximately 50 percent stronger wet than regular viscose. Modal is particularly prized in underwear and T-shirt applications for its exceptional softness, moisture absorption (50 percent better than cotton), and resistance to stiffening after washing.
Question 4: What is 'Tencel' (lyocell) and why is it considered more environmentally sustainable than conventional viscose?
- Tencel is a branded name for organic cotton
- Tencel/lyocell is regenerated cellulosic fiber produced in a closed-loop solvent system where over 99 percent of the solvent is recovered and reused, versus conventional viscose which uses toxic chemicals in an open process (Correct answer)
- Tencel is a synthetic fiber developed to replace silk
- Tencel is less sustainable than conventional viscose due to its energy requirements
Correct answer: Tencel/lyocell is regenerated cellulosic fiber produced in a closed-loop solvent system where over 99 percent of the solvent is recovered and reused, versus conventional viscose which uses toxic chemicals in an open process
Lyocell (Tencel is Lenzing's brand) is produced by dissolving wood pulp in a non-toxic NMMO solvent in a closed-loop system that recovers and reuses 99 percent or more of the solvent, compared to conventional viscose which uses carbon disulfide and releases toxic effluents.
The conventional viscose process uses carbon disulfide (a toxic solvent) and produces sulfur compounds and zinc in wastewater. Lyocell's NMMO solvent is low-toxicity and the closed-loop system recovers almost all of it. The wood pulp source (eucalyptus or beech trees grown on land unsuitable for food crops, no irrigation required) adds to the sustainability case. Tencel fibers also have excellent performance properties: exceptional softness, moisture regulation, and a characteristic smooth, draping quality.
Question 5: What is 'microfiber' and what properties make it valuable in fashion applications?
- Microfiber refers to any very small fiber regardless of type
- Synthetic fibers finer than 1 denier per filament, creating exceptionally soft, lightweight, tightly woven fabrics with superior drape, moisture-wicking, and wind resistance (Correct answer)
- A type of recycled polyester from plastic bottles
- Microfiber is a natural fiber from very fine wool fleece
Correct answer: Synthetic fibers finer than 1 denier per filament, creating exceptionally soft, lightweight, tightly woven fabrics with superior drape, moisture-wicking, and wind resistance
Microfibers are synthetic fibers finer than 1 denier (compared to 1 to 1.5 denier for standard nylon/polyester). Their extreme fineness enables dense fabric constructions with exceptional softness, drape, and functional properties including water resistance and moisture wicking.
Standard polyester is approximately 1.5 denier; microfibers are 0.1 to 0.7 denier. The extremely fine filaments create more fibers per unit area, enabling tighter weave structures and softer hand. Applications include: peachskin suede-effect fabrics, high-performance activewear, wind-resistant outerwear, and cleaning cloths. One environmental concern is that microfibers shed during washing, passing through water treatment facilities into water bodies.
Question 6: What does 'thread count' measure in woven fabrics and what are its limitations as a quality indicator?
- The total number of threads in a garment from seam to seam
- The number of warp and weft threads per square inch; a useful indicator of fabric fineness but not a complete quality indicator, as yarn quality, fiber type, and finishing significantly affect performance (Correct answer)
- The tensile strength rating of a fabric
- The number of times fabric can be washed before deterioration
Correct answer: The number of warp and weft threads per square inch; a useful indicator of fabric fineness but not a complete quality indicator, as yarn quality, fiber type, and finishing significantly affect performance
Thread count measures how many warp and weft threads are in one square inch of woven fabric. A higher count generally indicates finer yarns and tighter construction, but it is just one quality factor alongside yarn quality, fiber source, and fabric finishing.
Thread count became a consumer marketing tool primarily in bedding, where very high counts (1000+) are often achieved by using multi-ply yarns counted as individual threads, a statistical manipulation. In fashion, thread count is relevant for shirting and fine lingerie fabrics. However, a 200-count Sea Island cotton will outperform a 400-count poor-quality cotton because fiber length, crimp, and spinning quality affect hand and durability more than thread count alone.
Fashion Designer Textile Science & Fiber Properties 2
What is the difference between 'woven' and 'knit' fabric structures and how does this affect garment construction?