A natural fiber is a raw material obtained from animal, vegetal or mineral source that is usually converted into nonwoven fabric like felt or paper or sopped into yarn to create woven clothes. Properties of natural fibers depend mainly on the nature of the plant or animal, the locality in which it is grown, the age of the plant or animal, and the extraction method used.
Vegetable fibers are cellulose based and include important fibers such as cotton, flax, and jute. They can be divided into groups depending on their origin within the plant. Cotton, kapok, and coir are fibers originating from the hair on the seeds or fruits. Flax, hemp, and jute, fibers found in the inner bast tissue of plant stems. Abaca, henequen, and sisal are fibers found as part of the fibrovascular system of the leaves.
Animal fibers consist of proteins from fur of animals, with the exception of silk filaments that are extruded by the larvae of moths. The animal, or protein-based, fibers include wool and mohair.
Mineral fibers are mainly used as fillers in thermal insulation and fireproofing materials. Some of the most used mineral fibers are asbestos, graphite, and glass.
All natural fibers, except for mineral fibers, have an affinity for water that facilitates dyeing in watery solutions. They also are nonthermoplastic (do not soften when heat is applied). At temperatures below the point at which they will decompose, they show little sensitivity to dry heat, and there is no shrinkage or high extensibility upon heating, nor do they become brittle if cooled to below freezing. Natural fibers tend to yellow upon exposure to sunlight and moisture and extended exposure results in loss of strength.
Historically mankind has been using natural fibers since the beginning of times, by using fibers of native species to make not just clothes but also buildings and cordage.
Source Natural Fibres on BSAMPLY