Complete information on the classification and properties of fibers



Fibers are the visible units of which yarn and then fabrics are made.

Fibers  ----> Yarn -----> Fabrics

Some fibers are short, others very long, some are kinky, scaly and rough, others are straight and smooth. They may have high or low tensile strength or are transparent, opaque, colored, or colorless, even or uneven in diameter. Fibers may be from natural sources or man-made. The major fibers can be classified as follows.

1. Natural Fibers

Natural fibers are those that can be seen in nature and classified further as vegetable, animal and mineral.

(a) Vegetable fibers:

These fibers are found in the cell walls of plants and are cellulose in composition. The common vegetable fibers are cotton, linen, jute, hemp, sisal, ramie and coir etc. Cotton contains about 91 percent of cellulose, so also hemp and flax contain approximately large amount. Cellulose fibers are low in resiliency so the fabrics wrinkle easily. Because of its high absorbency nature, these fibers are comfortable for summer wear.

(b) Animal fibers:

Animal fibers, produced by animals or insects are protein in composition. Silk and wool are the most well known animal fibers used for textile. Wool grows from the skin of sheep and silk is unwound from the cocoon of a moth caterpillar known as silkworm. Other animal fibers are hair fibers such as camel, mohair, cashmere and rabbit etc. Animal fibers are very resilient and wrinkles go out between wearing. However, they are bad conductors of heat and build up static electricity in cold and dry weather. They are destroyed by concentrated mineral acids but the specific action of the dilute acids is not very harmful on either.

(c) Mineral fiber:

Mineral fibers, like asbestos, are mined from certain types of rock. This is practically the only natural mineral fiber. This fiber is inorganic and used for fire-proof fabrics, fire-proof curtains and screens and for many industrial uses. It is also used for floor and table mats.

2. Man-made Fibers

Man-made fibers are otherwise known as 'manufactured' or artificial fibers. These are derived from various sources of different nature, like cellulose, thermoplastic, protein and minerals in nature.

(a) Cellulose fibers:

Cellulose fibers are produced by man taken from the natural material of cellulose from cotton linters and wood pulp, processed it chemically and changed its form and several other characteristics into fibers of various lengths. Examples of man-made cellulose fibers are rayon, acetate, triacetate etc.

(b) Synthetic fibers:

These are another group of man made fibers. Synthetic fibers have been and are still being created by research chemists imitating properties of other fibers, to develop other characteristics, or to combine certain properties. These fibers are synthesized by combining carbon, oxygen, hydrogen and other simple chemical elements into large, complex molecular combination or structures called 'Polymers'. Examples of synthetic fibers are nylon, aramid, polyester, acrylic, vinyon etc.

(c) Man-made protein fiber:

Some fibers have been produced from the products as corn, processed it chemically and converted into man-made protein fibers, such as ardil, vicara and caslen etc.

(d) Minerals, Metallic and Rubber fibers:

Man-made fibers created from other sources are mineral fibers, metallic fibers and rubber fibers. Glass fibers are produced by mining and refining such metals are aluminum, silver and gold. Rubber fibers are made from the sap tapped from the rubber tree.

There are various types of fibers and not all fibers can be used in the manufacture of fabrics. The fibers intended for clothing must have the following primary properties.

1. Staple:

It is the dimension of the fiber, such as the length and diameter. A fiber has to be long and fine enough for satisfactory use. The longer the fiber, the more will be the strength of the yarn. Silk is a long fiber, but wool and cotton are short. Hence, silk produces fine, smooth and uniform fabrics with better draping qualities than the coarser fibers.

2. Elasticity:

Fibers must be pliable enough to wrap round each other to produce a yarn, producing a better fabric. The fabric must resist crushing by bearing impacts and spring back to their original state. This property makes the fabrics droppable, wrinkle resistant and helps to maintain their shape and size.

3. Strength:

The fiber must also be strong enough to be spun into yarn and subsequently into durable fabrics. The strength of the textile fibers is very much influenced by the moisture in the atmosphere. In general, vegetable fibers are stronger when they are wet, while some man-made fibers like rayon and acetate are weaker in that state.

4. Uniformity to staple:

Fibers of uniform staple (dimension) spin better and make a smoother and uniform yarn.

5. Spinning quality:

In order to have good spinning quality, fibers must have cohesiveness as this prevents fiber slippage. Four main factors contribute to cohesiveness between fibers and yarn is fineness of staple, nature of surface, pressure through twisting and length of the fibers.

Besides these above mentioned properties, there are also other required properties such as: density or specific gravity, luster, moisture regain, flammability, resistance to heat, alkalis, acids and bleaches etc. The durability of a fabric is more or less determined by the fiber from which it is made. A strong fiber produces strong cloth and long fibers tend to make strong yarns.