Filament Fibres and Synthetic Fibres

How Semi-Synthetic Filaments Are Made

Semi-synthetic filaments are produced in a way similar to natural silk production: a spinning solution is forced through spinnerets, and as it emerges, it solidifies into fine filaments. These filaments are then either cut into staple fibres or twisted into yarns suitable for textile manufacture. Viscose rayon is the clearest example of this process in action.

Viscose Rayon: Properties and Care

Viscose rayon is made from purified cellulose. Unlike cotton and linen, though, rayon’s cellulose structure is chemically altered, which means rayon undergoes chemical reactions more easily than cotton and linen do. Rayon absorbs more moisture from the atmosphere than cotton; when wet, it absorbs water, swells, and loses strength temporarily. Wet rayon stretches easily, but regains its original properties once it dries — which is exactly why rayon fabrics require careful washing.

Chemically, rayon behaves similarly to cotton and linen: alkalis don’t affect it much, but acids damage it quickly, and the same dyes used for cotton also work on rayon. It can be manufactured in different thicknesses and forms as needed, and is produced both as filament yarns and as staple fibres.

Polyester: From Niche Fabric to Industry Staple

Polyester fibres are among the most important synthetic textile fibres in use today, though that wasn’t always obvious. Initially, polyester was mainly used for men’s shirts and women’s dresses; it later expanded into jackets, coats, and many other garments, and because of its attractive appearance and durability, polyester fabrics quickly became popular throughout the textile industry.

At first, staple polyester fibres were mainly used for men’s summer clothing — but because polyester has poor moisture absorption, this caused real discomfort for the wearer. That problem was later reduced by blending polyester with cotton and wool. By 1977, staple polyester fibres were also being used to produce thick fabrics similar to cotton materials, and polyester later found its way into carpets and tyre cords too, although those early products weren’t especially satisfactory.

Polyester: Properties, Uses & Care

Polyester fibres are extremely strong and durable — they don’t tear or wear out easily, and their strength actually increases when the filaments are stretched and heat-treated during manufacture; strong sewing threads can be made from polyester for exactly this reason. These fibres absorb very little moisture, so water-based stains don’t easily stick to them, and polyester garments dry very quickly after washing without needing strong soaps.

That same low moisture absorption has a downside, though: tightly fitting polyester garments can feel uncomfortable against the body, a problem modern finishing processes have helped reduce. When ironing polyester, only moderate heat should be used, since excessive heat can melt the fabric — in fact, many polyester garments don’t need ironing at all. Dust and dirt are also easily attracted to polyester due to static electricity, meaning polyester clothes need more frequent washing, though again, modern finishing methods have helped reduce this drawback. For upholstery fabrics specifically, polyester is considered a better material than nylon.

Acrylic Fibres: A Wool Substitute

Acrylic fibres are soft, warm, lightweight, and elastic fibres that resemble wool in both appearance and touch, made from a polymer called polyacrylonitrile. Two main types are in common use: fibres containing 85% or more polyacrylonitrile are classified as acrylic fibres (examples: Orlon, Acrilan, Creslan), while fibres containing between 35% and 85% polyacrylonitrile are called modacrylic fibres (examples: Dynel, Verel).

Acrylic fibres have a bright appearance and smooth texture similar to wool, but are lighter in weight and more elastic, and don’t lose strength easily from friction. Because of these wool-like qualities, acrylic fibres are often used as a direct substitute for wool — in sweaters, blankets, carpets, curtains, industrial ropes, and tents, as well as vehicle interiors and seat covers. Since acrylic absorbs very little water, it dries quickly after washing, and dust and dirt are easy to remove from it.

Spandex: Built for Stretch

Spandex is a synthetic fibre defined by its exceptional elasticity. It was developed by DuPont in 1958 under the name ‘Lycra’. It’s a highly stretchable fibre that can extend from 3 to 15 times its original length — usually around 8 times — and still return to its original shape. Its basic material is polyurethane, which is highly compatible with rubber and other fibres and blends well with them; spandex fibres are also very smooth and soft in all conditions. Because of this combination of elasticity and comfort, spandex is mainly used for tight-fitting, stretchable garments such as tracksuits, swimming costumes, and body-fitting sportswear.

Nylon: Strength and Its Trade-offs

Nylon is the strongest synthetic fibre, made from chemical (petroleum-based) materials, and is one of the lightest fibres available — even as it ages, its strength doesn’t reduce easily. It’s highly durable, elastic, and resistant to wear and tear, which makes it widely used for both garments and industrial products: trousers, shirts, curtains, blouses, ropes, fishing nets, tents, industrial fabrics, and vehicle interiors.

Nylon’s important properties line up neatly: it’s very strong and long-lasting, light in weight, flexible and elastic, easy to maintain, and dries quickly while absorbing very little water. It can also be produced in very fine fibres and is easy to weave into different fabric types, which is a big part of why it’s so widely used in modern textile production.

That said, nylon has real disadvantages too: it melts easily under high heat, can be damaged by sunlight over time, and may feel uncomfortable in hot conditions because of its low breathability. Knowing both sides — the strength and the heat sensitivity — is what lets a designer choose nylon for the right application rather than the wrong one.

Comparing the Three Synthetic Fibres