Before we build its first city, its first castles, man made fabrics to cover himself. And he continued to manufacture them for thousands of years using fiber as raw material of vegetable or animal.
In plants, the fibers form the backbone that supports soft and pulpy parts of the leaves, roots and stems. In animals the fibers are instead in meat, skin, muscle and fur. All these fibers are extremely thin (their length is in fact about two thousand times their thickness) and consist of a long chain of molecules roughly parallel to each other. The plant fibers like cotton and flax, are cellulose, which is a compound of carbon, hydrogen and oxygen; animal fibers such as wool and silk, are made from many kinds of proteins, compounds of carbon, hydrogen , oxygen, nitrogen and sometimes sulfur (in wool).
To meet the needs of current methods of manufacturing and modern machinery, the fibers must be strong, durable, flexible, shiny and nearly uniform in size. Expected to be at least 12 mm (preferably 35 mm or more) is often just a few centimillimetro. They should be rough or wrinkled, so tightly intertwined when they are twisted to form a yarn, thereby increasing the resistance to flow and prevent the fibers on each other when subject to tension.
Only some of the natural fibers have all or most of these requirements, among these are cotton, very strong and resilient, wool, warm and uncreasable, silk, soft and shiny, and linen, crisp and bright. Cortical fibers, which eomprem gift jute, hemp, sisal and ramie are strong and resilient, but too rough to make clothes is used especially for rope, twine, bags and mats.
Since the ability of natural fibers are limited, the textile industry fully exploit man-made fibers that have been produced over the last 75 years. Between 1890 and 1920, chemists have discovered how to make many varieties of cotton fiber from the pulp and wood. Those who have had success pili were rayon viscose rayon and cellulose acetate, which is still being manufactured on a large scale. Initially, the fibers of rayon were called artificial silk for their silky smoothness and for their great luster.
Like all natural fibers, rayon absorbs water and s’inspessisce when washed, but there is a Bifforema: natural fibers remain strong when wet and swollen, the cotton becomes even stronger; Rayon, however, when it absorbs a quantity of water equal to its weight, lost about a third of its strength. This weakening is only temporary, because once dry rayon regains all its initial properties. It is clear, however, that the quality of a fiber is better if it loses its force when it is washed.
The discovery of nylon by Carothers was particularly important because the nylon, which is the first of the so-called synthetic fibers, is at least two times stronger than cotton, absorbs a small amount of water and keeps intact its shape even when wet. The success of nylon led to the discovery of other synthetic fibers with similar properties.
No fiber has all the advantages or disadvantages of all we talked about. Natural fibers and rayon fibers first resist heat and those organic solvents that are sometimes used in dry cleaning. On the other hand, they are attacked by moths and bacteria. The new synthetic fibers, however, are not attacked by insects and bacteria, but we ruin ironed iron is hot.
Since the rayon and natural fibers quickly absorb water are particularly suitable for clothing that more easily come into contact with sweat. For the same reason you can dye and dressing with substances soluble in water. But the fabrics of synthetic fibers repel water and are therefore by dressing and dyeing processes more complex and expensive. Also to be spun and woven synthetic fibers require special procedures.