Zylon

Last updated
Zylon
Poly(p-phenylene-2,6-benzobisoxazole).svg
Names
IUPAC name
poly(p-phenylene-2,6-benzobisoxazole) [1]
Identifiers
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Zylon (IUPAC name: poly(p-phenylene-2,6-benzobisoxazole)) is a trademarked name for a range of thermoset liquid-crystalline polyoxazole. This synthetic polymer material was invented and developed by SRI International in the 1980s and manufactured by Toyobo. [2] In generic usage, the fiber is referred to as PBO. [3]

Contents

Zylon has 5.8 GPa of tensile strength, [4] which is 1.6 times that of Kevlar. Additionally, Zylon has a high Young's modulus of 270 GPa, meaning that it is stiffer than steel. Like Kevlar, Zylon is used in a number of applications that require very high strength with excellent thermal stability. The material has been used in body armour, in tennis racquets, table tennis paddles, and in snowboards, in various medical applications, and in some of the Martian rovers.


Usage

Body armor

Zylon gained wide use in U.S. police officers body armor protection in 1998 with its introduction by Second Chance Body Armor, Inc. in its "Ultima" and "Ultimax" protective vests. At least as early as 2002 August, Point Blank Body armor offered "Fusion" [5] and as early as October, it offered "Legacy". [6] Armor Holdings's Safariland offered ZERO-G Platinum™ as its Zylon option, [7] [8] and oldest brand, its very own American Body Armor, had its most premier option also made with Zylon. Zylon body armor panels sometimes cost twice as much as Kevlar or 35% more than other advanced materials. [9] Despite "sticker shock", the marketing for Zylon body armor described incredibly low weight and thickness, but shockingly high protection, causing some to refer to it as a "miracle fiber". [10]

The incident and the aftermath

Protective vests constructed with Zylon were questioned in late 2003 when Oceanside, CA Police Officer Tony Zeppetella's and Forest Hills, PA Police Officer Ed Limbacher's vests both failed, leaving Zeppetella mortally wounded and Limbacher seriously injured.

On Sept 15 2003, Second Chance's president and CEO wrote a letter about Zylon and what his company's position about Zylon, and what their reaction was going to be. [11] He started by stating that the ULTIMA® line had 30 "saves". He described two years of testing "200 ULTIMA® vests from 37 different agencies in 19 different States".

He then said "Unfortunately, for all involved these results indicated the unexpected decrease in the ZYLON®fiber strength. ZYLON®fibers in various forms are used widely within our industry. Although inconsistent, these results have led us to where we are today. ULTIMA® and ULTIMAX® vests, as you know them today, have been discontinued from our product line."

The company would offer a "Performance Pac" to "account the worst-case performance scenarios of used, in service vests", for free.

Stephen Croskrey, President and CEO of Armor Holdings Products Division (Owners of American Body Armor, PROTECH™ and Safariland®) put out a letter as a reaction to the statements by Second Chance. In the letter, the CEO states that he found the "unexpected decrease" statement by Second Chance to be vague. He then said his company and Toyobo tested the material regularly, and that it was degrading at a rate typical compared to other materials. Finally, he stated that for his company, all incoming lot of materials had some tested, and they regularly received used tests to test. [12]

The realization and end to Zylon's use in body armor

Some studies subsequently reported that the Zylon vests might degrade over time [13] and leave their wearers with less protection than expected. Second Chance eventually recalled all of its Zylon vests, which led to its bankruptcy. The company once was able to claim that it held over 50% of the market for law enforcement body armor, all by itself. [14] This explains why 98,000 vests were recalled by Second Chance alone. [15] Comparable vests cost as much as $1450 at the time, or over $2100 at the end of 2014. [16]

In early 2005, Armor Holdings, Inc. recalled its Zylon-based products, and decreased the rated lifespan warranty of new vests from 60 months to 30 monthss. [17] In August 2005, AHI decided to discontinue manufacturing all of its Zylon-containing vests. This was largely based on the actions of the U.S. government's National Institute of Justice, which decertified Zylon for use in its approved models of ballistic vests for law enforcement. [18]

The United States Justice Department launched numerous investigations into possible violations of the False Claims Act regarding the defective vests. Throughout the course of litigation, settlements totaling more than $136 million were reached with 18 entities involved in the production and sale of Zylon vests. The investigations concluded after nearly two decades when the final settlement was obtained with material supplier Honeywell International in late 2022. [19]

Space elevator research

A competition was held in the Wirefly X Prize Cup in Las Cruces, New Mexico, US, on October 20–21, 2006. A team from the University of British Columbia entered into the Tether Challenge, using a construction made from Zylon fibers. The house tether used by Spaceward, that the other teams would have to beat in strength by 50% in the 2007 Spaceward games, [20] was made of Zylon.

High-altitude balloon science

Zylon is used by NASA in long-duration, high-altitude data collection. Braided Zylon strands maintain the structure of polyethylene superpressure balloons. Zylon is the material of choice due to its low weight, high tensile strength, and thermal properties. [21]

Motorsport

Since 2001 Zylon tethers are used in Formula One to attach the wheels to the chassis, thus preventing the wheel from ejecting into a crowded area in the event of an accident which causes the wheel to become airborne. Starting in the 2007 season, the driver's cockpit must now be clad in special anti-penetration panels made of Zylon. [22] In 2011, a Zylon strip was introduced to reinforce the top of the racing helmet visor [23] and provide an overlap between the visor and helmet for additional protection after Felipe Massa's 2009 injury. The Indy Racing League began using Zylon in 2008. [24]

Standing rigging

On modern racing yachts, Zylon is used for parts of the standing rigging. It is used as shrouds and stays. The PBO (polybenzoxazole) fiber is degraded by UV light, seawater, and chafing (the problem that caused Zylon to be removed from usage in protective vests for police usage, as shown above), and is therefore protected by a synthetic melted-on jacket. It is claimed to be 65% lighter than traditional rigging at 110–130% of the price of rod rigging. [25] Based on laboratory tests, superior durability is also claimed.

Parachutes

SpaceX uses Zylon for the suspension lines on their Mk3 parachutes. Four Mk3 parachutes serve as the main parachutes on each of SpaceX's human-rated Crew Dragon spacecraft. [26]

Conductive textile

Zylon has been incorporated as the base fiber for some conductive textiles, where the Zylon fiber is plated with nickel, copper, silver, or gold. The conductive fiber is used for electronic textiles, EMI shielding in woven or knit sheets, or as a braid over wires, and for signal transmission or current conduction. This conductive fiber combines the advantages of Zylon (strength, resistance to high temperatures, durability, lightweight, etc.) with the electrical properties of various metals. The conductive yarns can be sewn, braided, knit, or simply insulated like a bare wire. [27]

Structural rehabilitation

PBO is the strongest and stiffest of commercially available fibers used to repair and strengthen concrete and masonry structures in externally bonded composite systems. [28] In this system, the fibers are produced in the form of a fabric mesh, and a cementitious mortar matrix bonds this to an existing structure.

Loudspeakers

Yamaha uses Zylon to make the speaker cones for its top-of-the-line NS-5000 speaker. [29]

Bicycle & wheelchair wheel spokes

Spinergy, Inc. produces wheels for bicycles and wheelchairs with PBO spokes. They claim their PBO fiber spokes act as a vibration and shock damper, while being lighter and stronger than steel spokes. [30]

See also

Related Research Articles

<span class="mw-page-title-main">Kevlar</span> Heat-resistant and strong aromatic polyamide fiber

Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tires. It is typically spun into ropes or fabric sheets that can be used as such, or as an ingredient in composite material components.

<span class="mw-page-title-main">Bulletproof vest</span> Form of body armour that protects the torso from some projectiles

A bulletproof vest, also known as a ballistic vest or bullet-resistant vest, is a type of body armour designed to absorb impact and prevent the penetration of firearm projectiles and explosion fragments to the torso. The vest can be either soft—as worn by police officers, security personnel, prison guards, and occasionally private citizens to protect against stabbing attacks or light projectiles—or hard, incorporating metallic or para-aramid components. Soldiers and police tactical units typically wear hard armour, either alone or combined with soft armour, to protect against rifle ammunition or fragmentation. Additional protection includes trauma plates for blunt force and ceramic inserts for high-caliber rounds. Bulletproof vests have evolved over centuries, from early designs like those made for knights and military leaders to modern-day versions. Early ballistic protection used materials like cotton and silk, while contemporary vests employ advanced fibers and ceramic plates. Ongoing research focuses on improving materials and effectiveness against emerging threats.

<span class="mw-page-title-main">Aramid</span> Class of synthetic fiber

Aramid fibers, short for aromatic polyamide, 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 marine cordage, marine hull reinforcement, as an asbestos substitute, and in various lightweight consumer items ranging from phone cases to tennis rackets.

Twaron is a para-aramid, high-performance yarn. It is a heat-resistant fibre, helps in ballistic protection and cut protection. Twaron was developed in the early 1970s by the Dutch company Akzo Nobel's division Enka BV, later Akzo Industrial Fibers. The research name of the para-aramid fibre was originally Fiber X, but it was soon called Arenka. Although the Dutch para-aramid fiber was developed only a little later than DuPont's Kevlar, the introduction of Twaron as a commercial product came much later than Kevlar due to financial problems at the Akzo company in the 1970s. As of 2000, Twaron had become a global material and had been integrated into the global markets. Twaron has been around for over 30 years.

<span class="mw-page-title-main">Stephanie Kwolek</span> Polish-American chemist who invented Kevlar (1923–2014)

Stephanie Louise Kwolek was a Polish-American chemist best known for inventing Kevlar. Her career at the DuPont company spanned more than 40 years.

<span class="mw-page-title-main">Personnel Armor System for Ground Troops</span> Military equipment

Personnel Armor System for Ground Troops is a combat helmet and ballistic vest that was used by the United States military from the early 1980s until the early or mid-2000s, when the helmet and vest were succeeded by the Lightweight Helmet (LWH), Modular Integrated Communications Helmet (MICH), and Interceptor body armor (IBA) respectively.

<span class="mw-page-title-main">Body armor</span> Protective clothing; armor worn on the body

Body armor, personal armor, armored suit (armoured) or coat of armor, among others, is armor for a person's body: protective clothing or close-fitting hands-free shields designed to absorb or deflect physical attacks. Historically used to protect military personnel, today it is also used by various types of police, private security guards, or bodyguards, and occasionally ordinary citizens. Today there are two main types: regular non-plated body armor for moderate to substantial protection, and hard-plate reinforced body armor for maximum protection, such as used by combatants.

<span class="mw-page-title-main">Bulletproofing</span> Provision for resisting fired bullets

Bulletproofing is the process of making an object capable of stopping a bullet or similar high velocity projectiles. The term bullet resistance is often preferred because few, if any, practical materials provide complete protection against all types of bullets, or multiple hits in the same location, or simply sufficient kinetic (movement) energy to overcome it.

<span class="mw-page-title-main">Gold Flex</span>

Gold Flex is a non-woven fabric manufactured by Honeywell from Kevlar, and is often used in ballistic vests and body armor. Gold Flex is lighter than woven Kevlar, Twaron and other Ballistic material. Gold Flex is a laminated material consisting of cross-laid, non-woven fibers in a resin matrix. The fibers are laid straight and not in a woven fabric configuration. When an object strikes this material, a "web" of its clusters absorb the impact and minimizes penetration.

<span class="mw-page-title-main">Ballistic nylon</span> Thick, tough, nylon fabric

Ballistic nylon is a thick, tough, nylon fabric with several uses. Ballistic nylon was developed by the DuPont corporation as a material for flak jackets for World War II airmen. It was called ballistic because, together with other components, it was intended to protect its wearers from flying debris and fragmentation from bullet and artillery-shell impacts.

Second Chance is an American body armor manufacturing company. The company was founded in the early 1970s by U.S. Marine and pizza delivery owner/driver Richard Davis. Davis developed the idea of a bulletproof vest after shooting three armed robbers in self-defense during a delivery. This incident was later documented in a 1995 book written by firearms instructor Massad Ayoob called The Ayoob Files: The Book.

<span class="mw-page-title-main">Sailcloth</span> Strong fabric of the type used to make ships sails

Sailcloth is cloth used to make sails. It can be made of a variety of materials, including natural fibers such as flax, hemp, or cotton in various forms of sail canvas, and synthetic fibers such as nylon, polyester, aramids, and carbon fibers in various woven, spun, and molded textiles.

<span class="mw-page-title-main">Ranger Body Armor</span> Military ballistic protection

Ranger Body Armor (RBA) is a US military-issue ballistic vest that was designed for, and used chiefly by, US Army 75th Ranger Regiment operators ("Rangers") in the 1990s and 2000s. The RBA system has since been replaced by other specialized body armor systems adopted by the United States Special Operations Command (USSOCOM).

<span class="mw-page-title-main">Conductive textile</span> Fabric which can conduct electricity

A conductive textile is a fabric which can conduct electricity. Conductive textiles known as lamé are made with guipé thread or yarn that is conductive because it is composed of metallic fibers wrapped around a non-metallic core or has a metallic coating. A different way of achieving conductivity is to weave metallic strands into the textile.

<span class="mw-page-title-main">Improved Outer Tactical Vest</span> US Army body armor

The Improved Outer Tactical Vest (IOTV) is an enhanced version of, and a replacement for, the older Outer Tactical Vest (OTV) component of the Interceptor multi-threat body armor system, as fielded by the United States Army beginning in the mid-2000s. The IOTV is compatible with the Deltoid and Axillary Protector System (DAPS) components, ESAPI, Enhanced Side Ballistic Inserts (ESBI), as well as the OTV's groin protector. A flame-resistant standalone shirt, the Army Combat Shirt (ACS), was designed in the late 2000s specifically for use with the IOTV.

Ceramic armor is armor used by armored vehicles and in personal armor to resist projectile penetration through its high hardness and compressive strength. In its most basic form, it consists of two primary components: A ceramic layer on the outer surface, called the "strike face," backed up by a ductile fiber reinforced plastic composite or metal layer. The role of the ceramic is to (1) fracture the projectile or deform the projectile nose upon impact, (2) erode and slow down the projectile remnant as it penetrates the shattered ceramic layer, and (3) distribute the impact load over a larger area, which can be absorbed by ductile polymer or metallic backings. Ceramics are often used where light weight is important, as they weigh less than metal alloys for a given degree of resistance. The most common materials are alumina, boron carbide, and, to a lesser extent, silicon carbide.

<span class="mw-page-title-main">Usage of personal protective equipment</span>

The use of personal protective equipment (PPE) is inherent in the theory of universal precaution, which requires specialized clothing or equipment for the protection of individuals from hazard. The term is defined by the Occupational Safety and Health Administration (OSHA), which is responsible for PPE regulation, as the "equipment that protects employees from serious injury or illness resulting from contact with chemical, radiological, physical, electrical, mechanical, or other hazards." While there are common forms of PPEs such as gloves, eye shields, and respirators, the standard set in the OSHA definition indicates a wide coverage. This means that PPE involves a sizable range of equipment. There are several ways to classify them such as how gears could be physiological or environmental. The following list, however, sorts personal protective equipment according to function and body area.

<span class="mw-page-title-main">Space tether</span> Type of tether

Space tethers are long cables which can be used for propulsion, momentum exchange, stabilization and attitude control, or maintaining the relative positions of the components of a large dispersed satellite/spacecraft sensor system. Depending on the mission objectives and altitude, spaceflight using this form of spacecraft propulsion is theorized to be significantly less expensive than spaceflight using rocket engines.

<span class="mw-page-title-main">6B2 ballistic vest</span> Soviet Ballistic vest

6B2 is a Soviet ballistic vest. It is the first serial mass issued body armor of the Soviet Armed Forces, designed on the eve of Soviet-Afghan war. It was introduced into service in 1981. Use of this vest decreased losses of Soviet troops and it became the basis for the further development of domestic personal protective equipment.

References

  1. Compendium of Polymer Terminology and Nomenclature - IUPAC Recommendations 2008 (PDF). Retrieved 2018-08-28.
  2. Nielson, Donald (2006). A Heritage of Innovation: SRI's First Half Century. Menlo Park, California: SRI International. pp. 11–7–11–10. ISBN   978-0974520810.
  3. Abegaz, Adane Z. (2013-12-18). Advanced Fiber Reinforced Composites as Confining Systems for RC Columns (Thesis). University of Miami Scholarly Repository. p. 7.
  4. Toyobo Co., Ltd. "Zylon® (PBO fiber)" (free download PDF) (Technical Information).
  5. "Point Blank Body Armor: BALLISTICS: Fusion". 2003-02-03. Archived from the original on 3 February 2003. Retrieved 2024-12-10.
  6. "Point Blank Body Armor: BALLISTICS: Legacy & Legacy Premier". 2003-02-03. Archived from the original on 3 February 2003. Retrieved 2024-12-10.
  7. "ZERO-G ArmorwearTM - Ballistic Performance - Constructions". 2004-05-19. Archived from the original on 19 May 2004. Retrieved 2024-12-19.
  8. "ZERO-G ArmorwearTM - Ballistic Performance - Materials". 2004-01-23. Archived from the original on 23 January 2004. Retrieved 2024-12-19.
  9. "ZERO-G ArmorwearTM - Ballistic Performance - Retail Prices (MSRP)". 2004-05-19. Archived from the original on 19 May 2004. Retrieved 2024-12-10.
  10. "Second Chance Body Armor". 2003-10-14. Archived from the original on 14 October 2003. Retrieved 2024-12-10.
  11. "Second Chance Body Armor". 2003-10-14. Archived from the original on 14 October 2003. Retrieved 2024-12-10.
  12. "Toyobo develops TOYOBO ESTER GS, an eco-friendly packaging film". Focus on Catalysts. 2019 (5): 4. May 2019. doi:10.1016/j.focat.2019.04.020. ISSN   1351-4180.
  13. "Zylon". Policeone.com. Retrieved 2014-03-20.
  14. "2NDCHANCE Home Page". 1998-02-01. Archived from the original on 1 February 1998. Retrieved 2024-12-19.
  15. "Firm's recall of bulletproof vests affects some local police officers". The Blade. Retrieved 2024-12-19.
  16. "ZERO-G ArmorwearTM - Ballistic Performance - Retail Prices (MSRP)". 2004-05-19. Archived from the original on 19 May 2004. Retrieved 2024-12-19.
  17. "New Jersey News". Archived from the original on 2016-03-03. Retrieved 2022-06-02.
  18. "NIJ Journal Issue No. 254: Body Armor Safety Initiative".
  19. "Honeywell to Pay $3.35 Million for Alleged False Claims for Zylon Bullet Proof Vests". 26 October 2022.
  20. Little, Brian (2007-10-19). "Spaceward Games 2007 | GeekDad". Wired. Wired.com. Retrieved 2014-03-20.
  21. Said, M.A.; Dingwall, Brenda; Gupta, A.; Seyam, A.M.; Mock, G.; Theyson, T. (December 2006). "Investigation of ultra violet (UV) resistance for high strength fibers". Advances in Space Research. 37 (11). Elsevier Ltd.: 2052–2058. Bibcode:2006AdSpR..37.2052S. doi:10.1016/j.asr.2005.04.098.
  22. Formula One press release. "FIA Rules & Regulations Sporting Regulations 2007". Archived from the original on 2007-01-26. Retrieved 2007-01-29.
  23. "Super Visor - Formula One helmets become even safer". Formula1.com. 2011-03-30. Archived from the original on 2013-08-25. Retrieved 2011-03-30.
  24. "Indy-Car Upgrades Planned For 2008, '09". AutoWeek.com. 2007-09-07. Retrieved 2007-09-17.
  25. "powerliterigging.com". powerliterigging.com. Retrieved 2014-03-20.
  26. "Elon Musk and NASA chief give an update on SpaceX's astronaut spacecraft". YouTube . 2019-10-10. Archived from the original on 2021-12-12.
  27. "Metal Clad Fiber - AmberStrand® Fiber". metalcladfibers.com. Retrieved 2017-06-15.
  28. Tumialan, Gustavo; De Luca, Antonio (Sep 2014). "FRCM Systems". Structure Magazine.
  29. "NS-5000 Technology". yamaha.com. Retrieved 2022-03-10.
  30. "Spinergy PBO spokes". spinergy.com. Retrieved 2023-06-28.