Man-made and regenerated: polyester, nylon, viscose and the rest

The phrase 'man-made fibre' covers two unrelated families. True synthetics are built from petrochemical polymers extruded as filament: polyester, nylon, acrylic, elastane. Regenerated fibres start from natural polymer, usually wood cellulose, which is dissolved and re-spun: viscose, lyocell, cupro, modal. Conflating them is the first error. A viscose dress is closer in behaviour to cotton than to the polyester lining beneath it, and a lyocell shirt is a cellulose fibre wearing a lab coat.

What unites them is intention. Every one of these fibres was engineered to solve a problem that nature left open: a cloth that sheds water, stretches and snaps back, drapes without wrinkling, or costs a fraction of silk. The trade-offs are real and measurable, from melt temperature to moisture regains to the environmental bill of the solvent or monomer. Understand the polymer and you can choose with eyes open rather than by slogan.

Polyester: the workhorse that melts before it burns

Polyester is polyethylene terephthalate, the same polymer as a drinks bottle, melt-spun into filament or staple. Its defining properties are hydrophobicity, high tensile strength, crease resistance and a low moisture regain of around 0.4 percent, which is why polyester feels clammy against skin in heat: it neither absorbs nor releases sweat, it holds it on the surface. Its great virtue is dimensional stability and easy care; it springs back from wrinkles and survives the tumble dryer at temperatures that would destroy wool.

The liability is heat. Polyester softens near 230 degrees Celsius and melts, so a hot iron leaves a permanent gloss or hole, and a cigarette ash burns a hole in seconds. It also sheds microfibres, the tiny plastic fragments released in every wash that now turn up in waterways and tissue. Recycled polyester, spun from post-consumer PET, cuts virgin oil use but does not stop shedding. Use polyester where water resistance and durability matter, accept the climate cost, and wash it in a filter bag to trap lint.

• Moisture regain ~0.4 percent: does not breathe like cellulose
• Softens ~230C: low iron temperature, no tumble heat abuse
• Sheds microplastics: use a capture bag, wash cold and full

Nylon: stronger than steel by weight, weaker in sun

Nylon, polyamide, was the first true synthetic fibre and remains the strongest common textile filament, with abrasion resistance that outperforms polyester and cotton by a wide margin. That is why it dominates hosiery, swimwear, luggage and technical outerwear. It is also hydrophilic compared with polyester, with a moisture regain near 4 percent, so it dries faster than cotton yet feels less clammy than polyester.

Its weaknesses are heat and light. Nylon yellows and loses strength under prolonged ultraviolet exposure, which is why older swimsuits go brittle, and it melts around 215 degrees Celsius. It also absorbs odour more readily than polyester because of its chemistry. Modern nylons like Cordura trade some hand-feel for toughness; bio-based nylons from castor oil cut the petroleum input but not the melt point. Reach for nylon where abrasion is the enemy and keep it out of the noon sun when you can.

Elastane: a fraction of yarn, all of the comfort

Elastane, known as spandex or Lycra, is a polyurethane filament with extraordinary stretch, returning to shape from up to five times its length. It is almost never used alone; it is a small percentage, typically 2 to 8, blended into cotton, nylon or polyester to give recovery that those fibres lack. That tiny fraction is the difference between jeans that bag at the knee and jeans that hold, between a fitted shirt that moves and one that rides up.

Elastane is heat-sensitive and degrades with chlorine and prolonged light, losing its snap long before the surrounding fibre wears out. A 'stretchy' garment that has gone loose has usually exhausted its elastane, not its cotton. Heat from a dryer or iron accelerates the breakdown, so stretch blends should be washed cool and dried flat or line-dried. Buy the stretch when you want the movement, and baby the elastane so the garment keeps its shape past one season.

A garment's life is often limited by its smallest component, not its largest.

Viscose: cellulose dissolved, not synthesised

Viscose, or rayon, begins as wood pulp cellulose that is chemically dissolved in alkali and carbon disulphide and then regenerated through a spinneret into filament. The result is a fibre chemically close to cotton but spun as continuous filament, which gives viscose its fluid drape, cool hand and silk-like sheen at a fraction of the cost. It takes dye vividly and breathes well, which is why it dominates affordable occasionwear and linings.

The cost is structure. Viscose is weak when wet, losing up to half its dry strength, so it stretches and shreds in aggressive washing and can shrink or distort badly. It also wrinkles and pills. Conventional viscose production is chemically dirty, using toxic carbon disulphide, though closed-loop and lyocell routes have cleaned that up. Treat viscose as a delicate cellulose: cool hand-wash, dry flat, never wring. It is a beautiful, honest cheap-silk substitute that punishes carelessness.

Lyocell and cupro: the closed-loop upgrades

Lyocell, sold as Tencel, is cellulose from sustainably farmed wood dissolved in a non-toxic amine oxide solvent that is recovered and reused at over 99 percent in a closed loop. The fibre is stronger than viscose wet or dry, resists shrinkage, and has a smooth rounded cross-section that feels cool and drapes with authority. It also fibrillates, so it is often given a gentle enzyme wash for a peach-skin hand. Cupro, by contrast, is spun from cotton linter, the waste fluff around cottonseed, regenerated into a filament that mimics silk and is prized for linings.

Both are genuine improvements on viscose in environmental terms and in performance, with lyocell the more robust of the two. They still need cool washing and avoid high heat, and lyocell can stiffen if tumbled hot. For the buyer who wants cellulose comfort without petrochemical content and with a cleaner conscience, lyocell is the most defensible modern choice and cupro the most silk-like lining available at modest cost.

• Lyocell: closed-loop solvent, strong wet and dry, cool hand
• Cupro: cotton linter waste, silk-like filament, excellent lining
• Both: wash cool, skip the hot tumble, skip the harsh bleach

Buying the right synthetic for the role

There is no virtue contest here. Polyester wins for water-shedding outerwear and easy-care shirting; nylon wins for anything abraded; elastane wins for movement; viscose and lyocell win for drape and breathability at low cost. The buyer's job is to match the polymer to the demand and to price the externalities honestly: microplastic shedding, petrochemical feedstock, and the chemical load of regenerated cellulose.

Read the composition label as a recipe, not a verdict. A 98 percent cotton, 2 percent elastane shirt tells you exactly what you are getting: cotton comfort with a little recovery. A 100 percent polyester 'tech' tee tells you to expect clammy but indestructible. Neither is wrong. Both are tools. Choose with the property in mind and the fibre stops being a moral question and becomes a specification.

The recycling question beyond polyester

Recycling is not only a polyester story. Nylon can be depolymerised back to caprolactam and re-spun, though the infrastructure is thinner and the output pricier than virgin; elastane is effectively unrecyclable because its urethane cross-links resist separation, which is why stretch blends are rarely accepted in textile take-back. Lyocell is different: its wood pulp is not recycled but its solvent loops at over ninety-nine percent, so the 'waste' is mostly recovered chemical and water, a cleaner cradle than a recycled one.

For the buyer, the practical move is to favour fibres whose loop is closed or whose monomer is recoverable, and to avoid mixed blends that no facility will split. A hundred-percent cotton or wool garment is easier to mechanically recycle than a cotton-polyester mix, where the two polymers must be separated at cost. Read the composition as a disposal instruction as well as a care one; the cloth you buy is the cloth a sorter will meet later, and mono-material is the kindness you leave them. The take-back reality is that most 'recyclable' claims cover only the monomer, not the dye or the finish, so a black nylon is rarely reborn black; colour and chemistry are stripped and the loop is partial. Read a recycling claim as a direction, not a receipt, and weight mono-material and closed-loop fibres above a label that merely says 'recycled'.

• Nylon: depolymerisable but infrastructure-poor and pricey
• Elastane: unrecyclable cross-links, avoid in take-back
• Lyocell: closed solvent loop, cleaner than mechanical recycling

Man-made and regenerated fibres are not an indictment of nature; they are answers to questions cotton, linen, wool and silk could never satisfy. Polyester sheds water and wrinkles, nylon shrugs off abrasion, elastane gives recovery, and lyocell delivers silk-like drape from a closed loop of wood pulp. The honest buyer reads the composition as a recipe and prices the trade-offs: microplastics against easy care, petrochemical feedstock against durability, solvent load against drape. None of these fibres is cheating. Each is a tool with a known failure mode. Learn the polymer, and the label stops being a slogan and starts being a specification you can actually use.