A **fibre** (also spelled as **fiber**) is a piece of material which is long, thin and flexible, like a length of thread. Plant fibres are the basis of fabric such as cotton. Silk and wool fibres come from animals. In the 20th century many artificial fibres were invented like nylon and polyester.

They are very important in the structure of plants and animals, because they hold tissues together.

There are many uses for fibres. They can be spun together into filaments, thread, string or rope. They can be woven in fabric or in composite materials

Natural fibre
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See the main article: Natural fiber
Natural fibers include those made by plants, animals, and geological processes. They can be classified according to where they came from:

* Vegetable fibers are based on arrangements of cellulose, often with lignin. Examples include cotton, hemp, jute, flax, abaca, piña, ramie, sisal, bagasse, and banana. Plant fibers are used to make paper and textile (cloth). It is also used as dietary fiber.
* Wood fiber is fiber that gotten from trees. They include groundwood, lacebark, thermomechanical pulp (TMP), and bleached or unbleached kraft or sulfite pulps.
* Animal fibers mainly consist of proteins. Examples are silkworm silk, spider silk, sinew, catgut, wool, sea silk and hair.
* Mineral fibers include the asbestos group. Asbestos is the only long mineral fiber that can be found in nature. Six minerals have been classified as "asbestos". They include chrysotile, amosite, crocidolite, tremolite, anthophyllite and actinolite. Short, fiber-like minerals include wollastonite and palygorskite.
* Biological fibers also known as fibrous proteins or protein filaments consist of biologically important proteins, mutations or other genetic defects can lead to severe diseases. For example, the collagen family of proteins, tendon, muscle proteins like actin, cell proteins like microtubules and many others, spider silk, sinew and hair etc.

Man-made fiber
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Man-made are fibers that are changed by man. Man-made fibers consist of regenerated fibers and synthetic fibers.

### Semi-synthetic fiber

Semi-synthetic fibers are made from raw materials with natural long-chain polymer structures. They are only changed and partially degraded by chemical processes. The first semi-synthetic fiber is rayon. Most semi-synthetic fibers are cellulose regenerated fibers.

#### Cellulose regenerated fibers

Cellulose fibers are a type of man-made fibers, regenerated from natural cellulose. The cellulose comes from many sources: rayon comes from tree wood fiber, bamboo fiber comes from bamboo, seacell comes from seaweed, etc.

Some examples of this type of fiber are:

* Rayon
* Bamboo fiber
* Lyocell, a brand of rayon
* Modal
* Diacetate fiber
* Triacetate fiber

### Synthetic fiber

See the main article: Synthetic fiber
Synthetic fibers come from synthetic materials such as petrochemicals.

#### Metallic fibers

See the main article: Metallic fiber
Metallic fibers can be gotten from ductile metals such as copper, gold or silver and extruded or deposited from more brittle ones, such as nickel, aluminum or iron.

#### Carbon fiber

See the main article: Carbon fiber
Carbon fibers are fibers that are mostly made up of carbon atoms. Carbon fibers are often based on oxidizing carbonized polymers through pyrolysis like PAN.

#### Silicon carbide fiber

In silicon carbide fibers the basic polymers are not hydrocarbons but polymers. About 50% of the carbon atoms are replaced by silicon atoms.

#### Fiberglass

See the main article: Fiberglass
Fiberglass are also man-made fibers that come from natural raw materials. It is made from a specific type glass, and optical fiber, which is made from purified natural quartz.

#### Polymer fibers

* Polymer fibers are a type of man-made fibers, which are based on synthetic chemicals. These fibers are made from:
	+ Polyamide nylon
	+ PET or PBT polyester
	+ Phenol-formaldehyde (PF)
	+ Polyvinyl chloride fiber (PVC) vinyon
	+ Polyolefins (PP and PE) olefin fiber
	+ Acrylic polyesters
	+ Aromatic polyamids (aramids)
	+ Polyethylene (PE), eventually with extremely long chains / HMPE
	+ Elastomers can even be used
	+ Polyurethane fiber
	+ Elastolefin
*

Related pages
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* Textile
* Optical fiber
* Tensile strength