Fibres: Natural, Synthetic & Blended
Where Fibres Come From
All textiles begin with a fibre — a fine, hair-like strand that is spun into yarn and woven, knitted or bonded into fabric. Fibres fall into two broad families: natural (sourced from plants and animals) and synthetic (manufactured from chemicals, usually derived from crude oil). Understanding the origin of each fibre is essential because it directly determines the fibre's properties and its environmental impact.
Natural Fibres
Cotton is a cellulose fibre harvested from the seed pod of the cotton plant, grown in warm climates such as India, the USA and China. It is soft, comfortable against the skin, strong when wet and highly absorbent — making it ideal for T-shirts, towels and bed linen. Cotton is breathable but creases easily and can shrink if washed at high temperatures.
Wool is a protein fibre shorn from sheep (and other animals such as alpacas and goats for specialist wools). It is naturally warm because the crimped fibre traps air pockets, and it has excellent moisture management — absorbing up to 30% of its own weight in water vapour without feeling wet. Wool is used for knitwear, suits and blankets. It requires careful washing because it felts if agitated in hot water.
Silk is a continuous protein filament produced by the silkworm (Bombyx mori) as it spins its cocoon. Silk is exceptionally smooth, lustrous and strong for its weight. It drapes beautifully and is used for luxury garments, scarves and linings. Silk is expensive because production is labour-intensive: the cocoons must be unreeled by hand in hot water to preserve the continuous filament.
Linen is made from the stem fibres of the flax plant. It is one of the oldest textile fibres known to humanity. Linen is stronger than cotton, highly absorbent, and becomes softer and more lustrous with washing. It is cool to wear in summer but creases severely. Linen is used for shirts, trousers, table linen and home furnishings.
Natural plant fibres (cotton, linen) are made of cellulose; natural animal fibres (wool, silk) are made of protein. This distinction matters: cellulose fibres generally absorb moisture well, while protein fibres naturally resist fire and can absorb moisture vapour without feeling damp.
Synthetic Fibres
Synthetic fibres are manufactured by extruding a liquid polymer through tiny holes called spinnerets to produce continuous filaments. The raw material is almost always derived from crude oil, a non-renewable petrochemical resource.
Polyester is the world's most widely produced synthetic fibre. It is strong, durable, wrinkle-resistant and dries very quickly — properties that make it ideal for sportswear, fleece jackets and workwear. Polyester does not absorb moisture well, which can make it feel clammy next to the skin during exercise, though modern microfibre versions draw sweat away by capillary action.
Nylon (polyamide) was the first fully synthetic fibre, developed in the 1930s. It is exceptionally strong and abrasion-resistant, making it popular for tights, hosiery, ropes, parachutes and backpack fabrics. Nylon is lightweight and recovers well from stretching, but like polyester it absorbs little moisture and can build up static charge.
Acrylic is often used as a cheaper substitute for wool because it is soft, lightweight and warm. Acrylic is resistant to sunlight degradation, making it useful for outdoor fabrics and upholstery. However, it pills readily (small balls of fibre form on the surface), it melts rather than burns and it is not biodegradable.
Elastane (brand name Lycra) is a polyurethane-based fibre that can stretch to about five times its original length and then recover its shape fully. Even a small percentage added to a fabric (2–5%) gives it significant stretch and recovery. Elastane is used in swimwear, cycling shorts, sportswear and stretch denim.
The manufacturing process is called melt spinning (for polyester and nylon) or wet spinning (for acrylic). In melt spinning, the polymer chips are melted and forced through a spinneret. The fine streams of polymer solidify in cool air to form continuous filaments, which are then drawn (stretched) under tension to align the polymer chains — this increases strength and reduces extensibility. Multiple filaments are bundled into a yarn. Filament yarns are smooth and lustrous; filaments can also be cut into short lengths called staple fibres to mimic the texture of natural fibres when spun.
Blended and Mixed Fibres
A blended fibre combines two or more fibre types in the same yarn to combine the best properties of each. The most common example is polycotton (typically 65% polyester, 35% cotton): polyester contributes durability, quick drying and wrinkle resistance; cotton contributes softness, breathability and comfort. Polycotton is used for school shirts, bed sheets and workwear.
A mixed fabric uses different fibres in the warp and weft yarns (the threads running lengthways and widthways in a woven fabric) rather than blending them in the same yarn. The result is a fabric with different properties in each direction. Blending and mixing allow designers to engineer performance characteristics that no single fibre could provide alone.
Blends are created to improve performance (e.g. stretch + strength), reduce cost (synthetic fibres are cheaper than silk or wool), and balance care requirements (machine-washable wool blends are easier to maintain than 100% wool). Always link each fibre in the blend to a specific benefit it contributes.
Ecological and Social Footprint of Fibre Production
No fibre is entirely without environmental or social impact. Cotton is the world's most pesticide-intensive crop — conventional cotton production uses roughly 6% of the world's pesticides despite occupying only 2.4% of its farmland. It also requires enormous volumes of water: it takes approximately 10,000 litres of water to produce 1 kilogram of cotton. Organic cotton avoids synthetic pesticides but yields less per hectare and is more expensive.
Synthetic fibres such as polyester and nylon depend on crude oil, a finite, non-renewable resource. Their production involves energy-intensive chemical processes and releases greenhouse gases. Crucially, synthetic fabrics shed microplastics — tiny plastic fragments — every time they are washed. These particles pass through wastewater treatment systems into rivers and oceans, entering the food chain. A single wash of a fleece jacket can release more than 700,000 microplastic fibres.
The social footprint of fibre production includes working conditions in cotton-farming communities (where pesticide exposure causes health problems), and in textile mills where low wages, long hours and poor safety standards remain common concerns in some producing countries. Fair trade certification schemes and industry codes of conduct aim to improve conditions, but enforcement is patchy across global supply chains.
One response to the environmental cost of virgin synthetic fibre is recycled polyester (rPET), made by melting down plastic bottles or post-consumer textile waste and extruding new filaments. Producing rPET uses approximately 59% less energy than virgin polyester. Many sportswear brands now use rPET extensively in their ranges. However, recycled synthetics still shed microplastics, and the sorting, cleaning and reprocessing of mixed-fibre garments remains technically challenging, so not all post-consumer textile waste can currently be recycled back into fibre.