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
knit or
woven into a fabric. Artificial fibers consist of regenerated fibers and synthetic fibers.
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. Most semi-synthetic fibers are cellulose regenerated fibers.
Cellulose regenerated fibers Cellulose fibers 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 •
diacetate fiber •
triacetate fiber. Historically, cellulose diacetate and -triacetate were classified under the term rayon, but are now considered distinct materials.
Synthetic fibers Synthetic come entirely from synthetic materials such as
petrochemicals, unlike those artificial fibers derived from such natural substances as cellulose or protein. 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.
Metallic fibers Metallic fibers 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 fibers are often based on oxidized and via
pyrolysis carbonized polymers like
PAN, but the end product is almost pure carbon.
Silicon carbide fiber Silicon carbide fibers, where the basic polymers are not
hydrocarbons but polymers, where about 50% of the carbon atoms are replaced by silicon atoms, so-called poly-carbo-
silanes. 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 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.
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 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. •
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 /
HMPE (e.g. Dyneema or Spectra). •
Elastomers 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
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.
Microfibers in
textiles refer to sub-denier fiber (such as polyester drawn to 0.5 denier).
Denier and
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, show smaller fibrils jutting out and away from the main fiber structure. == Typical properties of selected fibers ==