Synthetic fibers belong to the broad family of chemical fibers. Unlike artificial fibers, they are derived primarily from fossil resources and obtained through a process of chemical synthesis.
While conventional synthetic fibers derive chiefly from hydrocarbons (oil, natural gas, coal), alternatives are now being developed that are made from renewable resources (corn, castor oil, cane sugar, etc.).
Following the invention of the first man-made fibers at the end of the 19th century, research into new fibers was accelerated. In the 1930s and 1940s, new plastic materials were developed, along with their first textile applications.
Generally stronger, potentially elastic, and easier to care for than natural or artificial fibers, synthetic fibers are also, and perhaps most importantly, cheap to produce – a factor which quickly garnered them widespread popularity.
Unsplash / Skylar Kang
Synthetics represent the lion’s share of all fibers produced – some 64% in 2021 – the vast majority of which is polyester. Synthetic fibers are nevertheless drawing growing criticism for their many negative impacts on the environment. These stem from their production – which relies on virgin hydrocarbons, requires large amounts of energy and results in greenhouse gas emissions – to their use – which disperses plastic micro-particles into the environment, involves blends that cannot be recycled, and creates problems at the end of a product’s life.
Recently we’ve seen the emergence of lower-impact alternatives, from recycled synthetic fibers made from renewable natural resources, to synthetic fibers with faster biodegradability, to help limit the release of microplastics. And though these developments are promising, they currently represent only a tiny fraction of an ever-accelerating production. Here is a list of synthetic fibers, filaments and membranes, classified by origin:
Polyurethane (PU) and its filament version, Elastane (EL/EA)
A synthetic material derived from petroleum, polyurethane is a urethane polymer. The textile industry uses polyurethane in three main ways:
- In membranes, for 2- or 3-layer assemblies that can help make fabrics breathable, waterproof, windproof and feather-proof.
- As a coating on knit or woven bases for decorative or protective ends – from waterproofing to lacquer, metallic or faux-leather effects.
- In filament form, this is elastane, also known as spandex. Elastane is never used on its own, but is instead spun together with all kinds of natural, artificial and synthetic fibers to add stretch to yarns and textiles. Its high shape-retention is a plus, but it is difficult to recycle, and has only a mediocre resistance to UV and chlorine.
Some trade names: LYCRA® (Invista), Elaspan (Invista), Dorlastan (Asahi), Roica (Asahi), Linel (Fillattice), RadiciSpandex (Radici Group), Creora (Hyosung)
Mixed fossil resources (oil, coal or gas)
Polyamides, also known as nylon (PA)
Polyamide fibers are polymers derived from coal or petroleum. They are renowned for their high strength. Lightweight, wrinkle-resistant, thermoplastic, quick-drying and recyclable, they have a wide range of applications, from lingerie to protective outerwear.
Polyesters (PES or PET)
Polyester is a synthetic fiber derived from fossil fuels. Its principle raw material is crude oil. These fibers have similar technical properties to polyamides, at a slightly lower price and quality level, making them very popular for ready-to-wear.
Polyester is currently the world’s most widely produced fiber (54% in 2021).
Unsplash / Subham Dhage
Acrylic is produced from a petroleum derivative and ammonia. It is created by the polymerization of the acrylonitrile molecule. Either pure or blended, the fiber is mostly used as a cheaper alternative to wool, thanks to its soft and fluffy feel, lightness, good heat insulation and wrinkle resistance. Acrylic is commonly used to make hosiery, knits, blankets and faux furs, and contributes to the spread of plastic microparticles.
Aramid fibers take their name from a shortening of the term “aromatic polyamides”. They’re mainly derived from petroleum using a chemical polymerization process. Their exceptional properties, such as strength, lightness and resistance to high temperatures, make them preferred materials for manufacturing bullet-proof vests, fire-protection clothing and reinforced tires, along with a range of textile applications requiring a high level of resistance.
Trade names: Kevlar® and Nomex® by DuPont™, Twaron® by Teijin Aramid
GORE-TEX, a registered trademark of W.L. Gore & Associates, is a microporous, ultrafine and water-repellent membrane.
It is produced using raw materials derived from natural gas. It is manufactured by expanding PTFE, better known by its trademark Teflon®. Its microporous aspect makes it completely waterproof, yet allows the skin to breathe by letting water vapor pass through it. GORE-TEX membranes are often laminated between two fabric layers to create a composite structure. This lamination can be elaborated in a variety of fabrics to obtain specific performance factors, such as abrasion resistance, heat-regulation, lightness and so on. These technical qualities make it the material of choice for outdoor clothing, accessories and equipment.
Coal or lime
Chlorofibers (from PVC)
Chlorofibers are obtained from PVC. Non-flammable, waterproof and wrinkle-resistant, providing good thermal, electrical and acoustic insulation, these fibers are rarely used to manufacture garments, but are used for furnishings with special technical properties.
Synthetic fibers from renewable natural resources
A synthetic fiber derived from plants, corn fiber is made by transforming carbohydrates (found in corn starch) into polymers. These polymers are heated, extruded and spun. Supple and breathable, corn fiber takes less energy to process than polyester, and its production waste is compostable.
The raw material for polyamide 11 (PA 11) is castor oil. Invented in France in 1947, its use in textiles declined in the 1970s, PA 11 being significantly more expensive than its fossil-based competitors. Nonetheless, this fiber is enjoying a resurgence of interest from brands seeking to work with synthetic fibers produced from renewable resources.
Fibers of other origins (coffee residue, sugar cane, agricultural waste, etc.)
New alternatives to conventional synthetics are gradually emerging.
These new fibers, derived from food-industry waste, have several advantages: they limit the use of fossil resources, recover waste materials, and don’t require additional land to be cultivated.
Unsplash / Antoni Shkraba
Polyester (PE or PES)
Polyethylene terephthalate (PET) – a specific kind of polyester that is widely used in the textile industry – was invented in 1941 by British chemists John Rex Winfield and James Tennant Dickson. The patent for it was bought by the U.S. company DuPont™ in 1945.
Production & Processing
PET is an oil derivative. Its raw materials are terephthalic acid and ethylene glycol. The polymerisation of these two monomers at high temperatures produces a liquid that, after solidifying, is shredded into even flakes. These flakes are then melted, filtered and spun. The resulting filaments are air-cooled and wound on bobbins. They are then hot-drawn, giving them their mechanical properties.
Polyester is very economical. It’s soft and drapes easily. It is thermoformable, it can retain pleats. It is quite easy to care for: it dries quickly and is crease-resistant. It’s easy to dye. It’s also very strong and resistant to mildew, fungus and insects.
Polyester feels somewhat rougher than other fibers such as cotton. It stains easily, and can encourage perspiration and odors. It’s also particularly sensitive to static electricity.
Polyester is made from petroleum, a non-renewable fossil resource. Its use is harmful to the environment. Its processing consumes a lot of energy and toxic chemicals and emits large quantities of greenhouse gases. Its upkeep releases large amounts of microfibers into the environment. It disintegrates very slowly.
Polyamide 6/6 was discovered in 1936 by the DuPont company, and industrial production began in 1938 (under the name nylon).
Unsplash / ActionVance
Other polyamides include Perlon (PA 6), Rilsan (PA 11, made using castor oil) and Kevlar. Some of these polyamides quickly found applications in the textile industry, especially to make parachute fabrics and hosiery.
Production & Processing
A polyamide is a polymer containing amide functions. There are different kinds, depending on the nature of the original monomers and the composition of the polymer backbone or chain. Polyamides can be derived from petroleum or coal and are obtained by polycondensation (polymer obtained by condensation) or polyaddition (polymer obtained by opening and then condensing a lactam). The base monomers used in polyamide manufacture are generally dicarboxylic acids and diamines.
Polyamide is soft, strong (even when wet) and highly elastic. It is quick-drying, crease-resistant and shrink-proof. It is resistant to mildew, fungus, and insects.
Polyamide is sensitive to heat, UV and static electricity.
Polyamide is made from petroleum, a non-renewable fossil resource. Its use is harmful to the environment. Its processing consumes a lot of energy and toxic chemicals, and emits large amounts of greenhouse gases. Its cleaning releases large amounts of microfiber into the environment. It takes a very long time to disintegrate at the end of its life.
As polyamide is infinitely recyclable, recycled polyamides are now available, such as ECONYL® by Aquafil Spa or Q-NOVA by FULGAR®.
Read also: Smart Key: Microfibers, macro-problem?