Textile Theory: Fibres

The textile industry is one of the oldest and largest industries in the world. With early humans first using skins and furs as coverings. Later, advancements in civilisation lead to the development of other fabric-like textiles, that were draped around the body. Further evolving into the full-scale textile manufacturing we see today, which includes a variety of specialised and smart fabrics.

But, as in the words of Maria (Julie Andrews) in The Sound of Music (1965):

"Let's start at the very beginning.

A very good place to start."

Fibre > Yarn > Fabric

Most textiles start off as fibres, with the fibres serving as the most basic element. Fibres are fine, hairlike strands that can be meshed together to create a textile, or combined to create yarn, which can then be woven or knitted into a fabric. Furthermore, fibres can either be natural in origin or manufactured. On the whole, fibres are the first step in the production of any fabric, thereby determining and influencing the characteristics of the yarn, final fabric, and end product.

Fibre categories

There are three main fibre categories, namely:

• Natural fibres, which are obtained from plants, animals, and minerals, i.e. cotton, wool, and asbestos;

• Manufactured or man-made fibres (the term 'synthetic' is no longer widely used in industry), which are commercially manufactured from chemicals, i.e. polyester, nylon, acrylic; and

• Regenerated manufactured fibres, which are fibres that are manufactured from a mixture of plant-based raw materials, such as wood pulp, and chemicals, i.e. viscose.

Fibre classification

Fibres can be classified as either being a staple or filament fibre.

Staple fibre

Staple fibres are short strands of fibre that are usually measured in centimetres. Almost all natural fibres come in this form, with manufactured fibres sometimes being cut into shorter staple fibres, depending on the final yarn, fabric, or product to be produced.

There are three groups of natural staple fibres namely, natural cellulosic fibres, natural protein fibres, and natural mineral fibres. Each which can be further classified as follows:

Natural cellulosic fibres

Natural cellulosic fibres are acquired from plants, and can be sub-classified as:

• Seed fibres, where the fibres develop within a seedpod, i.e. cotton;

• Bast fibres, which are fibres found within the stem of a plant, i.e. flax from which linen is made; and

• Leaf fibres, which are obtained from plant leaves, i.e. piña, which is made from pineapple leaves.

Natural protein fibres

Protein fibres can either come from animals, in the form of wool, fleece, or hair; or from insects, such as silk from the silkworm (although silk is also classified as a natural protein fibre, it is not a staple fibre, but comes in filament form, which I will discuss next). In general, the majority of animal fibres are regarded as luxury fibres.

Natural mineral fibres

The only true natural mineral fibre is asbestos and like most natural fibres it is also a short staple fibre.

Filament fibre

Unlike staple fibres, filament fibres are long and continuous, hairlike strands, which can be measured in meters or even kilometers. The only natural occurring filament fibres are silk from silkworms or spiders (natural protein fibres). Other than that, all filament fibres are manufactured, since the fibres are extruded as filament fibres during production (imitating silkworms and spiders). These manufactured filament fibres can then be cut into shorter staple fibres, as determined by the desired yarn, fabric, or final end-product characteristics. Since all manufactured fibres start out as filament fibres, regenerated manufactured fibres also falls into this classification.

Fibre characteristics

As mentioned before, fibres ultimately determine the final characteristics of yarns and fabrics, and therefore also the final end-product. Properties we consider during the purchase of an item, such as aesthetics, durability, comfort, appearance retention, care, environmental concerns, and cost are all influenced by the textiles basic building blocks: fibres. For this reason, a sound understanding of the properties of different fibres can help consumers (like me and you) make wiser selections, when purchasing textile products. Furthermore, knowledge of the proper care techniques for different fibres, fabrics, and finishes will not only support after purchase satisfaction, but also prolong the life of textile items.

Fibre blends

After mentioning the fact that fibre characteristics has such a big influence on the properties of yarns, fabrics, and textile products, it is also important to mention that many commercial items consist of fabric blends. This means that two or more fibres have been blended into a single yarn or fabric, thereby gaining a variety of fibre characteristics from each fibre within the blend.

Staple fibres that are blended together, before being spun into yarn, are known as intimate blends. Although the blending process can also be done during the yarn or fabric production stages (this will be covered in later posts).

Fabric burn tests

Fabric burn tests are good preliminary tests to categorise fibres. Although burn test should not be used as the only method of identifying a fibre, it does provide a fair amount of valuable information. Which can be used with further evidence to make a positive fibre identification, especially when the fibre type is unknown (looking at all the quilters and sewists with a large collection or 'stash' of fabric, like mine...).

When fibres are spun into yarns or fabricated into textiles, it becomes difficult to distinguish between natural and manufactured fibres. Making it much more difficult to evaluate, classify, and use fabrics to their optimum.

Observe the following when doing a burn test:

• Fabric reaction when flame approaches;

• How quickly the fabric ignites and burns;

• What happens after removing the flame;

• Colour of the smoke;

• Smell or odour;

• Residue left behind after burning.

When doing fabric burn tests, an observation of the fabric behaviour will give you an indication of the type of fibre(s) you are dealing with. However, fibre blends may be more difficult to identify, as a more predominant fibre may mask the presence of a secondary fibre, making the test unreliable. Equally, fabric finishes may also influence a burn test, especially flame-retardant finishes.

* Fibre (South African/UK English) vs Fiber (US English)