The world of fibres and yarns

For a fibre to be considered ideal for apparel use, the fibre needs to have certain basic properties, feel LR Chandru and R Vijayasekar.

What do handbags, hovercrafts, habitats, hang-gliding, halyards, healthcare and horticulture have in common? Natural fibres like wool, cotton, silk, jute and linen were used to make textiles more than 5,000 years ago. Textiles, once used primarily as a means of protecting oneself from the environment and for ornamentation, has moved beyond the home into construction, transportation, aerospace, agriculture and medicare, over the last hundred years. A dazzling array of new fibres, yarns, fabrics and textile based products have made textiles an indispensable part of our lives.

For a fibre to be considered ideal for apparel use, the fibre needs to have certain basic properties. Strength is obviously the first. Linen and silk are the strongest fibres followed by cotton and then wool. Wool, though weaker than the others, scores high on elasticity, which is the extent to which a fibre can be stretched and then returned to its normal condition. The high elastic property of wool offsets its lower strength. Linen is the least elastic among natural fibres. Elasticity and strength to a large extent decide the resilience of a fabric. Resilience refers to the extent to which a fabric can recover after being deformed by crushing or compressing. Here, woolen fabrics score high, while Linen fabrics are quite stiff and wrinkle easily, a factor that has caused a decreasing preference for linen for apparel use. Other natural fibres like jute, coir, hemp and sisal fail to make the grade and are relegated for use as sacking material, mats, brushes and ropes.

Given that climatic conditions affect the choice of fibres used for clothing, wool with its excellent warmth giving and insulating properties, is a natural choice in winter. Cotton and linen are summer favorites because of their higher heat conductivity. Which of these fibres are the most comfortable for clothing? Difficult question. Defining fabric comfort properties is a rather complex subject. In addition to the factors mentioned above, the type of fibre, the hairiness of the yarn, the fineness of the yarn, the twist in the yarn, the type of weave, the closeness of the weave and the chemical and physical treatment given to the finished fabric, all contribute to this rather abstract property called ´comfort´.

The undisputed reign of natural fibres ended in 1905 when the first man made fibre, viscose rayon was successfully produced on mass scale from wood pulp. Envisaged as a substitute for silk, because of its soft feel and luster, its low wet strength and propensity to degrade in sunlight, caused it to lose popularity as an apparel material in the early forties. Further research led to development of better varieties of rayon and in 1955, the introduction of high-wet-modulus (HWM) rayon led to its revival for use in sheets, towels, and apparel.

Today higher strength variants of this fibre called Modal and Lyocell have once again revived rayon as a high comfort and low cost fibre for apparel use, more so, because rayon is one of the few man-made fibres that is fully bio-degradable.

The onslaught of synthetic polymer based man-made fibres began in 1935 with the invention of Nylon by DuPont; Introduced in 1939 as fabric, nylon aimed to replace natural silk and went on to dominate the stockings market within a few years. Before the world wars, natural fibres to a large extent fulfilled the apparel requirements of the world populace. Post war, population increase and the increasing requirement of textile material for non-apparel use in hitherto unthought-of applications spurred the development of a variety of petrochemical based man-made fibres that rapidly found acceptance, as their properties could be tailor made to s