Kevlar
Overview
 
Kevlar is the registered trademark
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

 for a para-aramid synthetic fiber
Synthetic fiber
Synthetic fibers are the result of extensive research by scientists to improve on naturally occurring animal and plant fibers. In general, synthetic fibers are created by forcing, usually through extrusion, fiber forming materials through holes into the air, forming a thread...

, related to other aramid
Aramid
Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is a portmanteau of "aromatic polyamide"...

s such as Nomex
Nomex
Nomex is a registered trademark for flame resistant meta-aramid material developed in the early 1960s by DuPont and first marketed in 1967.- Properties:...

 and Technora
Technora
Technora is an Aramid that is useful for a variety of applications that require high strength or chemical resistance. It is a brandname of the company Teijin.-Production:...

. Developed at DuPont
DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

 in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires. Typically it is spun into ropes or fabric
Fabric
A fabric is a textile material, short for "textile fabric".Fabric may also refer to:*Fabric , the spatial and geometric configuration of elements within a rock*Fabric , a nightclub in London, England...

 sheets that can be used as such or as an ingredient in composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...

 components.

Currently, Kevlar has many applications, ranging from bicycle tire
Tire
A tire or tyre is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...

s and racing sails to body armor
Bulletproof vest
A ballistic vest, bulletproof vest or bullet-resistant vest is an item of personal armor that helps absorb the impact from firearm-fired projectiles and shrapnel from explosions, and is worn on the torso...

 because of its high tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...

-to-weight ratio; by this measure it is 5 times stronger than steel on an equal weight basis.
Encyclopedia
Kevlar is the registered trademark
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

 for a para-aramid synthetic fiber
Synthetic fiber
Synthetic fibers are the result of extensive research by scientists to improve on naturally occurring animal and plant fibers. In general, synthetic fibers are created by forcing, usually through extrusion, fiber forming materials through holes into the air, forming a thread...

, related to other aramid
Aramid
Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is a portmanteau of "aromatic polyamide"...

s such as Nomex
Nomex
Nomex is a registered trademark for flame resistant meta-aramid material developed in the early 1960s by DuPont and first marketed in 1967.- Properties:...

 and Technora
Technora
Technora is an Aramid that is useful for a variety of applications that require high strength or chemical resistance. It is a brandname of the company Teijin.-Production:...

. Developed at DuPont
DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

 in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires. Typically it is spun into ropes or fabric
Fabric
A fabric is a textile material, short for "textile fabric".Fabric may also refer to:*Fabric , the spatial and geometric configuration of elements within a rock*Fabric , a nightclub in London, England...

 sheets that can be used as such or as an ingredient in composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...

 components.

Currently, Kevlar has many applications, ranging from bicycle tire
Tire
A tire or tyre is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...

s and racing sails to body armor
Bulletproof vest
A ballistic vest, bulletproof vest or bullet-resistant vest is an item of personal armor that helps absorb the impact from firearm-fired projectiles and shrapnel from explosions, and is worn on the torso...

 because of its high tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...

-to-weight ratio; by this measure it is 5 times stronger than steel on an equal weight basis. When used as a woven material, it is suitable for mooring lines and other underwater applications.

A similar fiber called Twaron
Twaron
Twaron is the brandname of Teijin Aramid for a para-aramid. It is a heat-resistant and strong synthetic fibre developed in the early 1970s by the Dutch company AKZO, division Enka, later Akzo Industrial Fibers. The research name of the para-aramid fibre was originally Fiber X, but it was soon...

 with roughly the same chemical structure was developed by Akzo in the 1970s; commercial production started in 1986, and Twaron is now manufactured by Teijin
Teijin
is a Japanese chemical and pharmaceutical company. It is listed on the Tokyo Stock Exchange with a market capitalisation of USD 3.9 billion. It operates in five main business segments: synthetic fibres; films and plastics; pharmaceuticals and home health care; trading and retail; and IT and new...

.

History

Poly-paraphenylene terephthalamide - branded Kevlar - was invented by Stephanie Kwolek
Stephanie Kwolek
Stephanie Louise Kwolek is a Polish-American chemist who invented poly-paraphenylene terephtalamide—better known as Kevlar. She was born in the Pittsburgh suburb of New Kensington, Pennsylvania. Kwolek has won numerous awards for her work in polymer chemistry.- Early life and education :Kwolek was...

 while working for DuPont. In anticipation of a gasoline shortage, in 1964 her group began searching for a new lightweight strong fiber to use for light but strong tires. The polymers she had been working with at the time, poly-p-Phenylene-terephthalate and polybenzamide, formed liquid crystal while in solution, something unique to those polymers at the time.

The solution was "cloudy, opalescent upon being stirred, and of low viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

" and usually was thrown away. However, Kwolek persuaded the technician, Charles Smullen, who ran the "spinneret", to test her solution, and was amazed to find that the fiber did not break, unlike nylon
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...

. Her supervisor and her laboratory director understood the significance of her discovery and a new field of polymer chemistry
Polymer chemistry
Polymer chemistry or macromolecular chemistry is a multidisciplinary science that deals with the chemical synthesis and chemical properties of polymers or macromolecules. According to IUPAC recommendations, macromolecules refer to the individual molecular chains and are the domain of chemistry...

 quickly arose. By 1971, modern Kevlar was introduced. However, Kwolek was not very involved in developing the applications of Kevlar.

Production

Kevlar is synthesized
Chemical synthesis
In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...

 in solution from the monomers 1,4-phenylene
Phenylene
The phenylene group is based on a di-substituted benzene ring . For example, poly is a polymer built up from para-phenylene repeating units....

-diamine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...

 (para-phenylenediamine
P-Phenylenediamine
p-Phenylenediamine is an organic compound with the formula C6H42. This derivative of aniline is a colorless solid, but typically samples can contain yellowish impurities arising from oxidation. It is mainly used as a component of engineering polymers and composites. It is also an ingredient in...

) and terephthaloyl chloride
Terephthaloyl chloride
Terephthaloyl chloride is the acid chloride of terephthalic acid and is one of two monomers used to make Kevlar, the other being p-phenylenediamine...

 in a condensation reaction
Condensation polymer
Condensation polymers are any kind of polymers formed through a condensation reaction, releasing small molecules as by-products such as water or methanol, as opposed to addition polymers which involve the reaction of unsaturated monomers...

 yielding hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

 as a byproduct. The result has liquid-crystalline
Liquid crystal
Liquid crystals are a state of matter that have properties between those of a conventional liquid and those of a solid crystal. For instance, an LC may flow like a liquid, but its molecules may be oriented in a crystal-like way. There are many different types of LC phases, which can be...

 behavior, and mechanical drawing orients the polymer chains in the fiber's direction. Hexamethylphosphoramide
Hexamethylphosphoramide
Hexamethylphosphoramide, often abbreviated HMPA, is a phosphoramide having the formula [2N]3PO. This colorless liquid is a useful polar aprotic solvent and additive in organic synthesis.-Structure and reactivity:...

 (HMPA) was the solvent initially used for the polymerization, but for safety reasons, DuPont replaced it by a solution of N-methyl-pyrrolidone and calcium chloride. As this process was patented by Akzo (see above) in the production of Twaron, a patent war ensued.

Kevlar (poly paraphenylene terephthalamide) production is expensive because of the difficulties arising from using concentrated sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

, needed to keep the water-insoluble polymer in solution during its synthesis and spinning
Spinning (textiles)
Spinning is a major industry. It is part of the textile manufacturing process where three types of fibre are converted into yarn, then fabric, then textiles. The textiles are then fabricated into clothes or other artifacts. There are three industrial processes available to spin yarn, and a...

.

Several grades of Kevlar are available:
  1. Kevlar K-29 – in industrial applications, such as cables, asbestos
    Asbestos
    Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...

     replacement, brake linings, and body/vehicle armor.
  2. Kevlar K49 – high modulus used in cable and rope products.
  3. Kevlar K100 – colored version of Kevlar
  4. Kevlar K119 – higher-elongation, flexible and more fatigue resistant.
  5. Kevlar K129 – higher tenacity for ballistic applications.
  6. Kevlar AP – has 15% higher tensile strength than K-29.
  7. Kevlar XP – lighter weight resin and KM2 plus fiber combination.
  8. Kevlar KM2
    Kevlar KM2
    Kevlar KM2 is a synthetic para-aramid fibre produced by DuPont. The fiber is an evolution of the original Kevlar fibre. The following quotes summarise Kevlar KM2's properties....

    – enhanced ballistic resistance for armor applications


The ultraviolet component of sunlight degrades and decomposes Kevlar, a problem known as UV degradation
UV degradation
Many natural and synthetic polymers are attacked by ultra-violet radiation and products made using these materials may crack or disintegrate . The problem is known as UV degradation, and is a common problem in products exposed to sunlight...

, and so it is rarely used outdoors without protection against sunlight.

Structure and properties

When Kevlar is spun
Spinneret (polymers)
Spinneret refers to a multi-pored device through which a plastic polymer melt is extruded to form fibers. Streams of viscous polymer usually exit into cool air or liquid to solidify. The individual polymer chains tend to align in the fiber because of viscous flow. This airstream liquid-to-fiber...

, the resulting fiber has a tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...

 of about 3,620 MPa, and a relative density
Relative density
Relative density, or specific gravity, is the ratio of the density of a substance to the density of a given reference material. Specific gravity usually means relative density with respect to water...

 of 1.44. The polymer owes its high strength to the many inter-chain bonds. These inter-molecular hydrogen bonds form between the carbonyl groups and NH centers. Additional strength is derived from aromatic stacking interactions between adjacent strands. These interactions have a greater influence on Kevlar than the van der Waals interactions and chain length that typically influence the properties of other synthetic polymers and fibers such as Dyneema. The presence of salts and certain other impurities, especially calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

, could interfere with the strand interactions and caution is used to avoid inclusion in its production. Kevlar's structure consists of relatively rigid molecules which tend to form mostly planar sheet-like structures rather like silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...

 protein.

Thermal properties

Kevlar maintains its strength and resilience down to cryogenic temperatures (−196 °C); in fact, it is slightly stronger at low temperatures. At higher temperatures the tensile strength is immediately reduced by about 10–20%, and after some hours the strength progressively reduces further. For example at 160 °C (320 °F) about 10% reduction in strength occurs after 500 hours. At 260 °C (500 °F) 50% strength reduction occurs after 70 hours.

Armor

Kevlar is a well-known component of personal armor
Personal armor
Personal armor is the whole of protecting clothing, designed to absorb and/or deflect slashing, bludgeoning, and penetrating attacks. They were historically used to protect soldiers, whereas today, they are also used to protect police forces, private citizens and private security guards or...

 such as combat helmet
Combat helmet
A combat helmet or battle helmet is a type of personal armor designed specifically to protect the head during combat. Helmets are among the oldest forms of personal protective equipment and are known to have been worn by the Akkadians/Sumerians in the 23rd century BC, Mycenaean Greeks since 17th...

s, ballistic face mask
Ballistic face mask
A ballistic face mask, also known as facial armor, is a type of personal armor designed to protect the wearer from ballistic threats. Ballistic face masks are usually made of kevlar or other bullet resistant materials and the inside of the mask may be padded for shock absorption, depending on the...

s, and ballistic vests. The PASGT helmet and vest
Personnel Armor System for Ground Troops
Personnel Armor System for Ground Troops, sometimes abbreviated to PASGT, was a combat helmet and ballistic vest used by the American military from the mid 1980s until 2005, when the system was succeeded by the Lightweight Helmet, Modular Integrated Communications Helmet, and Interceptor body...

 used by United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 military forces from the 1980s into 2005 both have Kevlar as a key component, as do their replacements. Other military uses include bulletproof facemasks used by sentries and spall liners used to protect the crews of armoured fighting vehicle
Armoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....

s. Even Nimitz-class aircraft carriers include Kevlar armor around vital spaces. Related civilian applications include Emergency Service's protection gear if it involves high heat (e.g., tackling a fire), and Kevlar body armor such as vests for police officers, security, and SWAT
SWAT
A SWAT team is an elite tactical unit in various national law enforcement departments. They are trained to perform high-risk operations that fall outside of the abilities of regular officers...

.

Personal protection

Kevlar is used to manufacture gloves, sleeves, jackets, chaps and other articles of clothing designed to protect users from cuts, abrasions and heat. Kevlar based protective gear is often considerably lighter and thinner than equivalent gear made of more traditional materials.

Sports equipment

It is used as an inner lining for some bicycle tire
Bicycle tire
A bicycle tire is a tire that fits on the wheel of a bicycle, unicycle, tricycle, quadracycle, bicycle trailer, or trailer bike. They may also be used on wheelchairs and handcycles, especially for racing...

s to prevent punctures, and due to its excellent heat resistance, is used for fire poi wicks. In table tennis, plies of Kevlar are added to custom ply blades, or paddles, in order to increase bounce and reduce weight. It is used for motorcycle safety clothing
Motorcycle safety clothing
To improve motorcycle safety many countries mandate the wearing of personal protective equipment such as protective clothing and helmets. Protective clothing may include certain types of jackets, gloves, boots, and pants. Jackets meant for motorcyclists are typically made of nylon, leather, or Kevlar...

, especially in the areas featuring padding such as shoulders and elbows. It was also used as speed control patches for certain Soap Shoes
Soap shoes
Soap is the brand name for shoes made for grinding. They were introduced by Chris Morris of Artemis Innovations Inc. with the brand name "Soap" in 1997. They have a plastic concavity in the sole, which allows the wearer to grind on objects such as pipes, handrails, and stone ledges...

 models.

In Kyudo
Kyudo
, literally meaning "way of the bow", is the Japanese art of archery. It is a modern Japanese martial art and practitioners are known as .It is estimated that there are approximately half a million practitioners of kyudo today....

 or Japanese archery
Archery
Archery is the art, practice, or skill of propelling arrows with the use of a bow, from Latin arcus. Archery has historically been used for hunting and combat; in modern times, however, its main use is that of a recreational activity...

, it may be used as an alternative to more expensive hemp
Hemp
Hemp is mostly used as a name for low tetrahydrocannabinol strains of the plant Cannabis sativa, of fiber and/or oilseed varieties. In modern times, hemp has been used for industrial purposes including paper, textiles, biodegradable plastics, construction, health food and fuel with modest...

 for bow string
Bow string
A bow string joins the two ends of the bow stave and launches the arrow. Desirable properties include light weight, strength, resistance to abrasion, and resistance to water...

s. It is one of the main materials used for paraglider suspension lines.

It is also used in the laces for the adidas F50
Adidas F50
The Adidas F50 range of football boots is Adidas's signature line of customisable, lightweight boots. First released in 2004, in the build-up to UEFA Euro 2004, the range was released as a successor of the X-Line range and as a direct competitor to Nike's Mercurial Vapor range, which had been...

 adiZero Prime football boot.

It is even used in sails for high performance racing boats.

It is increasingly being used in the "peto", the padded covering which protects the picadors' horses in the bullring.

Audio equipment

Kevlar has also been found to have useful acoustic properties for loudspeaker cones, specifically for bass and midrange drive units.

Drumheads

Kevlar is sometimes used as a material on marching snare drums. It allows for an extremely high amount of tension, resulting in a cleaner sound. There is usually a resin poured onto the Kevlar to make the head airtight, and a nylon top layer to provide a flat striking surface. This is one of the primary types of marching snare drum heads. Remo
Remo
Remo is a male given name of Latin origin - see Romulus and Remus.Remo may also refer to:* Remo, an American drum skin company* Remo , another name for the German wine grape Riesling* Remo language, a Panoan language of Brazil and Peru...

's "Falam Slam" Patch is made with Kevlar and is used to reinforce bass drum heads where the beater strikes.

Woodwind reeds

Kevlar is used in the woodwind reeds of Fibracell. The material of these reeds is a composite of aerospace materials designed to duplicate the way nature constructs cane reed. Very stiff but sound absorbing Kevlar fibers are suspended in a lightweight resin formulation.

Other uses

Frying pans

Kevlar is sometimes used as a substitute for Teflon in some non-stick frying pans.

Rope, cable, sheath

The fiber is used in woven rope and in cable, where the fibers are kept parallel within a polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...

 sleeve. The cables have been used in suspension bridge
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...

s such as the bridge at Aberfeldy in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

. They have also been used to stabilize cracking concrete cooling towers by circumferential application followed by tensioning to close the cracks. Kevlar is widely used as a protective outer sheath for optical fiber cable
Optical fiber cable
An optical fiber cable is a cable containing one or more optical fibers. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed....

, as its strength protects the cable from damage and kinking. When used in this application it is commonly known by the trademarked name Parafil.

Electricity generation

Kevlar was used by scientists at Georgia Institute of Technology
Georgia Institute of Technology
The Georgia Institute of Technology is a public research university in Atlanta, Georgia, in the United States...

 as a base textile for an experiment in electricity-producing clothing. This was done by weaving zinc oxide
Zinc oxide
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...

 nanowire
Nanowire
A nanowire is a nanostructure, with the diameter of the order of a nanometer . Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important —...

s into the fabric. If successful, the new fabric would generate about 80 milliwatts per square meter.

Building construction

A retractable roof of over 60,000 square feet (5,575 square metres) of Kevlar was a key part of the design of Montreal's Olympic stadium
Olympic Stadium (Montreal)
The Olympic Stadium is a multi-purpose stadium in the Hochelaga-Maisonneuve district of Montreal, Quebec, Canada built as the main venue for the 1976 Summer Olympics...

 for the 1976 Summer Olympics
1976 Summer Olympics
The 1976 Summer Olympics, officially known as the Games of the XXI Olympiad, was an international multi-sport event celebrated in Montreal, Quebec, Canada, in 1976. Montreal was awarded the rights to the 1976 Games on May 12, 1970, at the 69th IOC Session in Amsterdam, over the bids of Moscow and...

. It was spectacularly unsuccessful, as it was completed ten years late and replaced just ten years later in May 1998 after a series of problems.

Brakes

The chopped fiber has been used as a replacement for asbestos in brake pads. Dust produced from asbestos brakes is toxic, while aramids are a benign substitute.

Expansion joints and hoses

Kevlar can be found as a reinforcing layer in rubber
Rubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

 bellows
Bellows
A bellows is a device for delivering pressurized air in a controlled quantity to a controlled location.Basically, a bellows is a deformable container which has an outlet nozzle. When the volume of the bellows is decreased, the air escapes through the outlet...

 expansion joints and rubber hose
Hose (tubing)
A hose is a hollow tube designed to carry fluids from one location to another. Hoses are also sometimes called pipes , or more generally tubing...

s, for use in high temperature applications, and for its high strength. It is also found as a braid layer used on the outside of hose assemblies, to add protection against sharp objects.

Particle physics experiment

A thin Kevlar window has been used by the NA48 experiment at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...

 to separate a vacuum vessel from a vessel at nearly atmospheric pressure, both 192 cm in diameter. The window has provided vacuum tightness combined with reasonably small amount of material (only 0.3% to 0.4% of radiation length
Radiation length
In physics, the radiation length is a characteristic of a material, related to the energy loss of high energy, electromagnetic-interacting particles with it.-Definition:High-energy electrons predominantly lose energy in matter...

).

Composite materials

Aramid fibers are widely used for reinforcing composite materials, often in combination with carbon fiber
Carbon fiber
Carbon fiber, alternatively graphite fiber, carbon graphite or CF, is a material consisting of fibers about 5–10 μm in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber...

 and glass fiber. The matrix for high performance composites is usually epoxy resin. Typical applications include monocoque
Monocoque
Monocoque is a construction technique that supports structural load by using an object's external skin, as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin or coachwork...

 bodies for F1 racing cars, helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

 rotor blades, tennis
Tennis
Tennis is a sport usually played between two players or between two teams of two players each . Each player uses a racket that is strung to strike a hollow rubber ball covered with felt over a net into the opponent's court. Tennis is an Olympic sport and is played at all levels of society at all...

, table tennis
Table tennis
Table tennis, also known as ping-pong, is a sport in which two or four players hit a lightweight, hollow ball back and forth using table tennis rackets. The game takes place on a hard table divided by a net...

, badminton
Badminton
Badminton is a racquet sport played by either two opposing players or two opposing pairs , who take positions on opposite halves of a rectangular court that is divided by a net. Players score points by striking a shuttlecock with their racquet so that it passes over the net and lands in their...

 and squash
Squash (sport)
Squash is a high-speed racquet sport played by two players in a four-walled court with a small, hollow rubber ball...

 racket
Racquet
A racquet or racket is a sports implement consisting of a handled frame with an open hoop across which a network of cord is stretched tightly. It is used for striking a ball in such games as squash, tennis, racquetball, and badminton...

s, kayak
Kayak
A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...

s, cricket
Cricket
Cricket is a bat-and-ball game played between two teams of 11 players on an oval-shaped field, at the centre of which is a rectangular 22-yard long pitch. One team bats, trying to score as many runs as possible while the other team bowls and fields, trying to dismiss the batsmen and thus limit the...

 bats, and field hockey
Field hockey
Field Hockey, or Hockey, is a team sport in which a team of players attempts to score goals by hitting, pushing or flicking a ball into an opposing team's goal using sticks...

, ice hockey
Ice hockey
Ice hockey, often referred to as hockey, is a team sport played on ice, in which skaters use wooden or composite sticks to shoot a hard rubber puck into their opponent's net. The game is played between two teams of six players each. Five members of each team skate up and down the ice trying to take...

 and lacrosse
Lacrosse
Lacrosse is a team sport of Native American origin played using a small rubber ball and a long-handled stick called a crosse or lacrosse stick, mainly played in the United States and Canada. It is a contact sport which requires padding. The head of the lacrosse stick is strung with loose mesh...

 sticks.

See also

  • Innegra S
    Innegra S
    Innegra S is the brandname of Innegrity for a polyolefin .-History:Dr. Brian Morin, current CEO of Innegrity began work on Innegra in 2004...

  • Vectran
    Vectran
    Vectran is a manufactured fibre, spun from a liquid crystal polymer created by Celanese Acetate LLC and now manufactured by Kuraray Co., Ltd. Chemically it is an aromatic polyester produced by the polycondensation of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid.- Properties...

  • Spider silk
    Spider silk
    Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...

  • Ultra high molecular weight polyethylene
    Ultra high molecular weight polyethylene
    Ultra-high-molecular-weight polyethylene , also known as high-modulus polyethylene or high-performance polyethylene , is a subset of the thermoplastic polyethylene. It has extremely long chains, with molecular weight numbering in the millions, usually between 2 and 6 million...


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