From fibre to fabric: classifying textiles

1Why this matters

Look at the labels inside your clothes: "100% cotton", "65% polyester, 35% cotton", "viscose". Each word tells you how the garment will feel, how warm it will be, whether it will crease or shrink, and how hot the iron may be. A tailor at the market, a shop assistant and a careful buyer all use this knowledge every day.

Before you can compare fabrics you need a way to sort them. This lesson follows a fabric from its smallest part, the fibre, and then classifies fibres by where they come from.

2Fibre, yarn and fabric

• A fibre is a fine, hair-like strand, the raw material of every textile. A cotton fibre is only a few centimetres long.
• A yarn is made by twisting fibres together, which is called spinning. Twisting makes the yarn strong and long enough to use.
• A fabric is a flat sheet made from yarns or fibres. Fabrics are made in three main ways:
  • woven: two sets of yarns cross over and under each other at right angles, like a mat (shirts, kitenge, bedsheets);
  • knitted: one yarn is looped into rows of interlocking loops, which makes the fabric stretch (T-shirts, jumpers, socks);
  • non-woven: fibres are pressed, matted or glued together without yarns (felt, and the stiffening inside collars).

Short fibres such as cotton and wool are called staple fibres. Very long, continuous fibres, such as silk and man-made fibres, are called filaments.

3Classifying fibres by where they come from

• Natural fibres are taken from plants or animals.
  • Plant fibres are made of cellulose: cotton (from the seed pod of the cotton plant), linen (from the stem of the flax plant) and sisal (from the leaves of the sisal plant, used in ropes, mats and many agaseke baskets).
  • Animal fibres are made of protein: wool (from the fleece of sheep) and silk (from the cocoon of the silkworm).
• Man-made fibres are produced in factories. Liquid material is pushed through the fine holes of a nozzle called a spinneret, and each jet hardens into a filament.
  • Regenerated fibres start from a natural material, usually wood pulp, which is dissolved and re-formed into fibres. Rayon, also called viscose, is the main one.
  • Synthetic fibres are made entirely from chemicals, mostly obtained from petroleum: polyester, nylon and acrylic.

A blend is a yarn or fabric made from two or more different fibres, such as polyester-cotton (often called polycotton). Blends combine the good points of each fibre.

Worked example: sorting a wardrobe

Mugisha reads the labels of six items and classifies each one.

Notice that the fibre and the construction are two separate questions: a cotton shirt is woven, while a cotton T-shirt is knitted, which is why only the T-shirt stretches.

Practice

Solution. Fibre, then yarn (fibres twisted together), then fabric (yarns woven or knitted).

Solution. Linen: natural, plant (cellulose). Silk: natural, animal (protein). Polyester: man-made, synthetic. Rayon: man-made, regenerated from wood pulp.

Solution. The wood pulp is dissolved in chemicals and re-formed into new filaments in a factory. The fibre does not exist in that form in nature, so it is classed as man-made (regenerated).

Solution. A knitted fabric is made of interlocking loops, and loops can open out and close again. In a woven fabric the yarns cross at right angles and are held tightly, so there is little room to stretch.