RAYON OR VISCOSE: These yarns are the same. It is known as Rayon in the USA, Viscose in the UK and Europe.
Rayon/Viscose is NOT Synthetic. It is made from wood pulp a naturally occurring cellulose based raw material. Rayon is a soft comfortable cloth and is the most absorbent of all cellulose fibers – even more so than cotton and linen. It is the coolest fabric to wear.
It can be blended with other yarns. E.g. cotton/viscose.
MODAL: is a cellulose fabric made up of wood pulp from the beech tree. Modal only uses beech wood. It is essentially a section of the viscose/rayon family that is acquired from a variety of trees. It has the same properties as rayon.
COTTON: a natural fiber made from the cotton bush. 100% cotton garments tend to wrinkle and must be ironed. Cotton can shrink the first time it is washed. Look for pre shrunk cotton fabrics. Lower quality cottons are prone to pilling.
BAMBOO COTTON: is regenerated cellulosic fiber. It is very soft and has excellent moisture absorption and ventilation qualities. Natural antibacterial (bamboo-kun) keep bacteria away from the fabric. It is eco friendly and biodegradable.
SILK: is made from the fibers of the cocoon of the Chinese Silkworm. It is spun into smooth, shiny, sleek fabric. Silk absorbs moisture making it cool to wear in summer and warm in winter.
WOOL: comes from animal’s coats. It is cozy and warm and will absorb up to 30% of its weight in moisture without feeling damp. It has very little shine or sheen. The finer wool yarns that have been carded well are not scratchy to wear.
Wool can be mixed with other yarns. E.g. Silk/wool.
POLYESTER: is a man made fabric chemically based. It is strong and resistant to creasing. Polyester garments keep their shape well. Often polyester is blended with cotton to help cotton keep its shape or memory. It is the easiest fabric to wash and does not require ironing.