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{{Short description|Natural or synthetic substance that is significantly longer than it is wide}}
{{other uses}}
{{Distinguish|Dietary fiber}}
{{pp-vandalism|small=yes}}
{{More citations needed|date=April 2009}}
{{Use American English|date=May 2025}}<!--This article uses American English, except for chemistry-related names, per [[MOS:ARTCON]]. For example, "aluminium" and "sulfur".-->
{{Use dmy dates|date=May 2025}}
[[File:Fibreoptic.jpg|thumb|A bundle of [[optical fibers]]]]

'''Fiber''' (spelled '''fibre''' in [[British English]]; from {{langx|la|fibra|links=no}})<ref>{{OEtymD|fiber}}</ref> is a [[#Natural fibers|natural]] or [[Fiber#Artificial fibers|artificial]] substance that is significantly longer than it is wide.<ref name="Kadolph 2002">{{Cite book |last=Kadolph |first=Sara |date=2002 |title=Textiles |publisher=[[Prentice Hall]] |isbn=978-0-13-025443-6 }}</ref> Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example [[Carbon fibers|carbon fiber]] and [[ultra-high-molecular-weight polyethylene]].

Synthetic fibers can often be produced very cheaply and in large amounts compared to natural fibers, but for clothing natural fibers have some benefits, such as comfort, over their synthetic counterparts.

{{TOC limit|3}}

== Natural fibers ==
{{Main|Natural fiber}}
[[File:PhilFIDA natural fibersA.jpg|thumb|Various natural fibers from plants found in the Philippines. Labels show the plant names]]
{{Fibre sidebar}}

Natural fibers develop or occur in the fiber shape, and include those produced by plants, animals, and geological processes.<ref name="Kadolph 2002" /> They can be classified according to their origin:
* [[fiber crop|Vegetable fiber]]s are generally based on arrangements of [[cellulose]], often with [[lignin]]: examples include [[cotton]], [[Cannabis sativa|hemp]], [[jute]], [[flax]], [[abaca]], [[piña]], [[ramie]], [[sisal]], [[bagasse]], and [[Banana#Fiber|banana]]. Plant fibers are employed in the manufacture of [[paper]] and [[textile]] (cloth), and [[dietary fiber]] is an important component of human nutrition.
* [[Wood fibre|Wood fiber]], distinguished from vegetable fiber, is from tree sources. Forms include groundwood, [[Lagetta lagetto|lacebark]], thermomechanical pulp (TMP), and bleached or unbleached [[Kraft process|kraft]] or sulfite pulps. Kraft and sulfite refer to the type of pulping process used to remove the lignin bonding the original wood structure, thus freeing the fibers for use in paper and [[engineered wood]] products such as [[fiberboard]].
* [[Animal fiber]]s consist largely of particular proteins. Instances are [[silkworm]] [[silk]], [[spider silk]], [[sinew]], [[catgut]], [[wool]], [[sea silk]] and hair such as [[cashmere wool]], [[mohair]] and [[Angora wool|angora]], fur such as sheepskin, rabbit, mink, fox, beaver, etc.
* [[Mineral fiber]]s include the [[asbestos]] group. Asbestos is the only naturally occurring long [[mineral]] fiber. Six minerals have been classified as "asbestos" including [[chrysotile]] of the [[Serpentine group|serpentine]] class and those belonging to the [[amphibole]] class: [[amosite]], [[crocidolite]], [[tremolite]], [[anthophyllite]] and [[actinolite]]. Short, fiber-like minerals include [[wollastonite]] and [[palygorskite]].
* Biological fibers, also known as [[fibrous proteins]] or [[protein filament]]s, consist largely of biologically relevant and biologically very important proteins, in which mutations or other genetic defects can lead to [[Collagen#Diseases|severe diseases]]. Instances include the [[collagen]] family of proteins,<ref name="Saad 1994">{{cite thesis |last=Saad |first=Mohamed |title=Low resolution structure and packing investigations of collagen crystalline domains in tendon using Synchrotron Radiation X-rays, Structure factors determination, evaluation of Isomorphous Replacement methods and other modeling |date=October 1994 |degree=PhD |publisher=Université Joseph Fourier Grenoble I |pages=1–221 |url=https://drive.google.com/open?id=0B3L_EN9hIuFTTkhuN2lrWEU4RDQ&authuser=0 |doi=10.13140/2.1.4776.7844}}</ref> [[tendons]], [[muscle proteins]] like [[actin]], and many others, such as [[spider silk]], [[sinew]], and [[hair]].

==Artificial fibers<span class="anchor" id="Chemical"></span>==
Artificial or chemical fibers are fibers whose chemical composition, structure, and properties are significantly modified during the manufacturing process. In fashion, a fiber is a long and thin strand or thread of material that can be [[Knitting|knit]] or [[Woven fabric|woven]] into a fabric.<ref>{{cite encyclopedia |url=http://global.britannica.com/EBchecked/topic/361113/man-made-fibre |date=2013 |title=man-made fibre |encyclopedia=Encyclopædia Britannica |publisher=[[Encyclopædia Britannica, Inc.]] }}</ref> Artificial fibers consist of regenerated fibers and synthetic fibers.

{{see also|fiber modification}}

===Semi-synthetic fibers===
Semi-synthetic fibers are made from raw materials with naturally long-chain [[polymer]] structure and are only modified and partially degraded by chemical processes, in contrast to completely synthetic fibers such as [[nylon]] (polyamide) or [[dacron]] (polyester), which the chemist synthesizes from low-molecular weight compounds by polymerization (chain-building) reactions. The earliest semi-synthetic fiber is the cellulose regenerated fiber, [[rayon]].<ref>{{cite journal |last=Kauffman |first=George B. |date=1993 |doi=10.1021/ed070p887|bibcode=1993JChEd..70..887K |title=Rayon: the first semi-synthetic fiber product |journal=Journal of Chemical Education |volume=70 |issue=11 |pages=887}}</ref> Most semi-synthetic fibers are cellulose regenerated fibers.

====Cellulose regenerated fibers<span class="anchor" id="Regenerated"></span>====
[[Cellulose fiber]]s are a subset of artificial fibers, regenerated from natural [[cellulose]]. The cellulose comes from various sources: rayon from tree wood fiber, [[bamboo fiber]] from bamboo, seacell from [[seaweed]], etc. In the production of these fibers, the cellulose is reduced to a fairly pure form as a viscous mass and formed into fibers by extrusion through spinnerets. Therefore, the manufacturing process leaves few characteristics distinctive of the natural source material in the finished products.

Some examples of this fiber type are:
* [[rayon]]
* [[Lyocell]], a brand of rayon
* [[Modal (textile)|Modal]]
* [[Cellulose diacetate|diacetate fiber]]
* [[Cellulose triacetate|triacetate fiber]].

Historically, cellulose diacetate and -triacetate were classified under the term rayon, but are now considered distinct materials.

===Synthetic fibers===
{{Main|Synthetic fiber}}

[[Synthetic fiber|Synthetic]] come entirely from synthetic materials such as [[petrochemical]]s, unlike those artificial fibers derived from such natural substances as cellulose or protein.<ref>{{cite encyclopedia |url=http://global.britannica.com/EBchecked/topic/578682/synthetic-fibre |date=2013 |title=synthetic fibre |encyclopedia=Encyclopædia Britannica |publisher=Encyclopædia Britannica, Inc. }}</ref>

Fiber classification in reinforced plastics falls into two classes: (i) short fibers, also known as discontinuous fibers, with a general aspect ratio (defined as the ratio of fiber length to diameter) between 20 and 60, and (ii) long fibers, also known as continuous fibers, the general aspect ratio is between 200 and 500.<ref>Serope Kalpakjian, Steven R Schmid. "Manufacturing Engineering and Technology". International edition. 4th Ed. Prentice Hall, Inc. 2001. {{ISBN|0-13-017440-8}}.</ref>

====Metallic fibers====
{{Main|Metallic fiber}}
[[Metallic fiber]]s can be drawn 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====
[[Carbon (fiber)|Carbon fibers]] are often based on oxidized and via [[pyrolysis]] carbonized polymers like [[Polyacrylonitrile|PAN]], but the end product is almost pure carbon.

====Silicon carbide fiber====
[[Silicon carbide]] fibers, where the basic polymers are not [[hydrocarbon]]s but polymers, where about 50% of the carbon atoms are replaced by silicon atoms, so-called poly-carbo-[[silane]]s. The pyrolysis yields an amorphous silicon carbide, including mostly other elements like oxygen, titanium, or aluminium, but with mechanical properties very similar to those of carbon fibers.

====Fiberglass====
{{See also|Glass#Fibreglass}}

[[Fiberglass]], made from specific glass, and [[optical fiber]], made from purified natural [[quartz]], are also artificial fibers that come from natural raw materials, [[silica fiber]], made from [[sodium silicate]] (water glass) and [[basalt fiber]] made from melted basalt.

====Mineral fibers====
Mineral fibers can be particularly strong because they are formed with a low number of surface defects; [[asbestos]] is a common one.<ref>{{cite book |first1=James Edward |last1=Gordon |first2=Philip |last2=Ball |title=The New Science of Strong Materials, or, Why You Don't Fall through the Floor |url=https://books.google.com/books?id=jyCFQgAACAAJ |access-date=28 October 2011 |date=2006 |publisher=[[Princeton University Press]] |isbn=978-0-691-12548-0}}</ref>

====Polymer fibers====
* Polymer fibers are a subset of artificial fibers, which are based on synthetic chemicals (often from [[petrochemical]] sources) rather than arising from natural materials by a purely physical process. 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 fiber|acrylic]] polyesters, pure [[polyester]] PAN fibers are used to make [[carbon fiber]] by roasting them in a low oxygen environment. Traditional acrylic fiber is used more often as a synthetic replacement for wool. Carbon fibers and PF fibers are noted as two resin-based fibers that are not [[thermoplastic]], most others can be melted.
** [[aramid|aromatic polyamids]] (aramids) such as [[Twaron]], [[Kevlar]] and [[Nomex]] thermally degrade at high temperatures and do not melt. These fibers have strong bonding between polymer chains
** [[polyethylene]] (PE), eventually with extremely long chains / [[Ultra-high-molecular-weight polyethylene|HMPE]] (e.g. Dyneema or Spectra).
** [[Elastomer]]s can even be used, e.g. [[spandex]] although urethane fibers are starting to replace spandex technology.
** [[polyurethane]] fiber
** [[Elastolefin]]
* Coextruded fibers have two distinct polymers forming the fiber, usually as a core-sheath or side by side. Coated fibers exist such as nickel-coated to provide static elimination, silver-coated to provide anti-bacterial properties and aluminum-coated to provide RF deflection for [[Chaff (radar countermeasure)|radar chaff]]. Radar chaff is actually a spool of continuous glass tow that has been aluminum coated. An aircraft-mounted high speed cutter chops it up as it spews from a moving aircraft to confuse radar signals.

====Microfibers====
Invented in Japan in the early 1980s, microfibers are also known as microdenier fibers. Acrylic, nylon, polyester, lyocell and rayon can be produced as microfibers. In 1986, Hoechst A.G. of Germany produced microfiber in Europe. This fiber made it way into the United States in 1990 by DuPont.<ref name="Cohen">{{cite book |last1=Cohen |first1=Allen |title=J. J. Pizzuto's Fabric Science |date=11 November 2011 |publisher=Fairchild Books |isbn=978-1-60901-380-6 |page=51 |edition=10th}}</ref>

[[Microfiber]]s in [[textiles]] refer to sub-denier fiber (such as polyester drawn to 0.5 denier). [[Units of textile measurement#Denier|Denier]] and [[Units of textile measurement#Tex|Dtex]] are two measurements of fiber yield based on weight and length. If the fiber density is known, you also have a fiber diameter, otherwise it is simpler to measure diameters in micrometers. Microfibers in technical fibers refer to ultra-fine fibers (glass or meltblown [[thermoplastics]]) often used in filtration. Newer fiber designs include extruding fiber that splits into multiple finer fibers. Most synthetic fibers are round in cross-section, but special designs can be hollow, oval, star-shaped or [[trilobal]]. The latter design provides more optically reflective properties. Synthetic textile fibers are often crimped to provide bulk in a woven, non woven or knitted structure. Fiber surfaces can also be dull or bright. Dull surfaces reflect more light while bright tends to transmit light and make the fiber more transparent.

Very short and/or irregular fibers have been called fibrils. Natural [[cellulose]], such as [[cotton]] or bleached [[Kraft paper|kraft]], show smaller fibrils jutting out and away from the main fiber structure.<ref>{{cite book |first=Hans-J. |last=Koslowski |title=Man-Made Fibers Dictionary |edition=Second |publisher=Deutscher Fachverlag |date=2009 |isbn=3-86641-163-4 }}</ref>

== Typical properties of selected fibers ==
Fibers can be divided into natural and artificial (synthetic) substance, their properties can affect their performance in many applications. Synthetic fiber materials are increasingly replacing other conventional materials like glass and wood in a number of applications.<ref>{{Cite book |title=Rheology of Filled Polymer Systems |last=Shenoy |first=Aroon |publisher=Kluwer Academic Publishers |date=1999 |isbn=978-0-412-83100-3}}</ref> This is because artificial fibers can be engineered chemically, physically, and mechanically to suit particular technical engineering.<ref>{{Cite book |last=Hollaway |first=C. |date=1990 |title=Polymers and Polymer Composites in Construction |publisher=Bulter and Tanner |isbn=978-0-7277-1521-0 |location=Great Britain |pages=209}}</ref> In choosing a fiber type, a manufacturer would balance their properties with the technical requirements of the applications. Various fibers are available to select for manufacturing. Here are typical properties of the sample natural fibers as compared to the properties of artificial fibers. 
{| class="wikitable"
|+Table 1. Typical Properties of Selected Natural Fibers<ref>{{Cite book |title=Design and Control of Concrete Mixtures". Sixteenth Edition |publisher=Portland Cement Association |date=2018 |isbn=978-0-89312-277-5 |location=United States of America |pages=237–247 }}</ref><ref name=":1">{{Cite web |url=https://omnexus.specialchem.com/polymer-properties |title=Polymer Properties – Omexus by Special Chem }}</ref>
|-
| '''Fiber type'''
| '''Fiber Diameter'''

'''(in)'''
| '''Specific Gravity'''
| '''Tensile Strength'''

'''(Ksi)'''
| '''Elastic Modulus'''

'''(Ksi)'''
| '''Elongation at Break'''

'''(%)'''
| '''Water Absorption'''

'''(%)'''
|-
| Wood Fiber

(Kraft Pulp)
| 0.001–0.003
| 1.5
| 51–290
| 1500–5800
| N/A
| 50–75
|-
| Musamba
| N/A
| N/A
| 12
| 130
| 9.7
| N/A
|-
| [[Coconut]] 
| 0.004–0.016
| 1.12–1.15
| 17.4–29
| 2750–3770
| 10–25
| 130–180
|-
| [[Sisal]] 
| 0.008–0.016<ref name=":2">{{Cite web |url=http://www.sisal.ws/page6/page7/page7.html |title=Sisal Fiber – World of Sisal}}</ref>
| 1.45<ref name=":2" />
| 40–82.4
| 1880–3770
| 3–5
| 60–70
|-
| Sugar Cane [[Bagasse]]
| 0.008–0.016
| 1.2–1.3
| 26.7–42
| 2175–2750
| 1.1<ref>{{Cite book |isbn=9781782421221 |title=Biofiber Reinforcements in Composite Materials |editor1-first=Omar |editor1-last=Faruk |editor2-first=Mohini |editor2-last=Sain |chapter=The use of sugarcane bagasse fibres as reinforcements in composites |first=M. |last=Sain|date=2014|publisher=Elsevier Science & Technology}}</ref>
| 70–75
|-
| [[Bamboo]]
| 0.002–0.016
| 1.5
| 50.8–72.5
| 4780–5800
| N/A
| 40–45
|-
| [[Jute]] 
| 0.004–0.008
| 1.02–1.04
| 36.3–50.8
| 3770–4640
| 1.5–1.9
| 28.64<ref>{{Cite journal |last=Narayanan |first=Venkateshwaran |date=2012 |title=Mechanical and Water Absorption Properties of Woven Jute/Banana Hybrid Composites |journal=Fibers and Polymers |volume=13 |issue=7,907–914 |pages=907–914 |doi=10.1007/s12221-012-0907-0}}</ref>
|-
| [[Elephant grass]]
| 0.003–0.016<ref name=":3">{{Cite journal |last=K. Murali Mohan |first=Rao |date=2007 |title=Tensile Properties of Elephant grass fiber reinforced polymer Composites |journal=Journal of Materials Science |volume=42 |issue=9,3266–3272 |pages=3266–3272 |doi=10.1007/s10853-006-0657-8}}</ref>
| 0.818<ref name=":3" />
| 25.8
| 710
| 3.6
| N/Ab
|-
| colspan="7" | a  Adapted from ACI 544. IR-96 P58, reference [12] P240 and [13]

b  N/A means properties not readily available or not applicable
|}
<br />
{| class="wikitable"
|+Table 2. Properties of Selected Artificial Fibers
|-
| '''Fiber type'''
| '''Fiber Diameter'''

'''(0.001&nbsp;in)'''
| '''Specific Gravity'''
| '''Tensile Strength (Ksi)'''
| '''Elasticity Modulus  '''

'''(Ksi)''' 
| '''Elongation at Break'''

'''(%)'''
| '''Water Absorption'''

'''(%)'''
| '''Melting Point'''

'''(°C)'''
| '''Maximum Working'''

'''Temp (°C)'''
|-
| [[Steel]] 
| 4–40
| 7.8
| 70–380
| 30,000
| 0.5–3.5
| nil
| 1370<ref name=":4">{{Cite web |url=https://www.allsealsinc.com/teadit/TypicalMetalProperties.pdf |title=Metallic Materials – TEADIT}}</ref>
| 760<ref name=":4" />
|-
| [[Glass]] 
| 0.3–0.8
| 2.5
| 220–580
| 10,400–11,600
| 2–4
| N/A
| 1300
| 1000
|-
| [[Carbon]]
| 0.3–0.35
| 0.90
| 260–380
| 33,400–55,100
| 0.5–1.5
| nil
| 3652–3697<ref>{{Cite web |url=https://www.americanelements.com/carbon-fiber-7440-44-0 |title=Carbon Fiber – Americans Elements}}</ref>
| N/A
|-
| [[Nylon]] 
| 0.9
| 1.14
| 140
| 750
| 20–30
| 2.8–5.0
| 220–265
| 199
|-
| [[Acrylic fiber|Acrylics]]
| 0.2–0.7
| 1.14–1.18
| 39–145
| 2,500–2,800
| 20–40
| 1.0–2.5
| Decomp
| 180
|-
| [[Aramid]]
| 0.4–0.5
| 1.38–1.45
| 300–450
| 9,000–17,000
| 2–12
| 1.2–4.3
| Decomp
| 450
|-
| [[Polyester]]
| 0.4–3.0
| 1.38
| 40–170
| 2,500
| 8–30
| 0.4
| 260
| 170
|-
| [[Polypropylene]] 
| 0.8–8.0
| 0.9
| 65–100
| 500–750
| 10–20
| nil
| 165
| 100
|-
| [[Polyethylene]]

   Low

   High
| 1.0-40.0

|
0.92

0.95
|
11–17

50–71
|725

|
25–50

20–30
|
nil

nil
|
110

135
|
55

65
|-
| colspan="9" | a  Adapted from ACI 544. IR-96 P40, reference [12] P240, [11] P209 and [13]

b  N/A means properties not readily available or not applicable
|}
The tables above just show typical properties of fibers, in fact there are more properties which could be referred as follows (from a to z):<ref name=":1" />

Arc Resistance, [[Biodegradation|Biodegradable]], Coefficient of Linear [[Thermal expansion|Thermal Expansion]], Continuous Service Temperature, [[Density|Density of Plastics]], [[Ductility|Ductile]] / [[Brittleness|Brittle]] Transition Temperature, Elongation at Break, Elongation at Yield, Fire Resistance, Flexibility, Gamma Radiation Resistance, Gloss, [[Glass transition|Glass Transition Temperature]], [[Hardness]], [[Heat deflection temperature|Heat Deflection Temperature]], Shrinkage, [[Stiffness]], [[Ultimate tensile strength]], [[Thermal insulation|Thermal Insulation]], [[Toughness]], [[Transparency and translucency|Transparency]], UV Light Resistance, Volume [[Electrical resistivity and conductivity|Resistivity]], Water absorption, [[Young's modulus|Young's Modulus]]

==See also==
{{Commons category|Fibers}}
* [[Ceramic matrix composite]]
* [[Dietary fiber]]
* [[Fiber crop]]
* [[Fiber simulation]]
* [[Glossary of differential geometry and topology|Fibers in Differential Geometry]]
* [[Molded pulp]]
* [[Axon]] – A nerve fiber
* [[Optical fiber]]

==References==
{{Reflist}}

{{Fibers}}
{{Textile arts}}

{{Authority control}}

[[Category:Fibers| ]]
[[Category:Materials]]
[[Category:Textiles]]