It's generally believed that natural fabrics are the most comfortable ones. I am not opposing the fact. I just want to highlight the characteristics of Spandex, which is a synthetic fabric yet very comfortable and gives a great fit to our garments.
Spandex is an elastic fiber, and it was introduced by DuPont under the trade name "Lycra" in 1958. The brand name, Lycra, got so famous that it became the synonym of spandex and now all the varieties of spandex were known as Lycra. It was developed as the alternative to rubber but proved to be so good that it left rubber far behind. It has better resistance to heat, oil, and abrasion in comparison to rubber. However, the quality due to which spandex is loved so much is its stretchability. It can be stretched to almost 500% of its length. It is lightweight, soft, smooth, supple, durable and has higher retractive ability i.e. it can bounce back in its original shape in a very effective manner. As such, it never leads to bagging and sagging of the garment.
All the characteristics of spandex are due to the variety of raw materials that are used to make the stretchable spandex fiber - prepolymers which produce the backbone of the fiber, stabilizers which protect the integrity of the polymer, and colorants. Apart from the basic prepolymers, catalysts etc. stabilizers, such as antioxidants, are added to protect the fibers from damaging sources like heat, light, atmospheric contaminants, and chlorine. These fibers are manufactured in four different ways- melt extrusion, reaction spinning, solution dry spinning, and solution wet spinning. However, solution dry spinning alone produces over 90% of the world's spandex fibers.
As far as application of spandex is concerned, it is widely used in making of active sports wear, work wear and garments that provide support such as hosiery, bra, corsets etc. The level of comfort and wicking ability of Spandex can't match any other fabric. Not only they are used in work wear and swim wear but also are gaining popularity for making apparels for plus sized population. Due to its many qualities, spandex give support as well as freedom of movement and ease to such people. The new seamless spandex not only supports a fuller figure, it also provides the illusion of a more toned frame.