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Well-known aramid polymers such as Kevlar, Twaron, Nomex, New Star, and Teijinconex) are prepared from diamine and diacid (or equivalent) precursors. These polymers can be further classified according to the linkages on the aromatic subunits. Nomex, Teijinconex, and New Star contain predominantly the meta-linkage.
Twaron (a brand name of Teijin Aramid) is a para-aramid, high-performance yarn. [1] It is a heat-resistant fibre, helps in ballistic protection and cut protection. [2] Twaron was developed in the early 1970s by the Dutch company Akzo Nobel's division Enka BV, later Akzo Industrial Fibers.
Liquid-crystal polymers are present in melted/liquid or solid form. [7] In solid form, the main example of lyotropic LCPs is the commercial aramid known as Kevlar. The chemical structure of this aramid consists of linearly substituted aromatic rings linked by amide groups.
Nomex is an example of a meta variant of the aramids (Kevlar is a para aramid). Unlike Kevlar, Nomex strands cannot align during filament polymerization and have less strength: its ultimate tensile strength is 340 MPa (49,000 psi). [2] However, it has excellent thermal, chemical, and radiation resistance for a polymer material.
In the diagram below, an aramid is made from two different monomers which continuously alternate to form the polymer chain. Aramids are aromatic polyamides: Aramids are aromatic polyamides: The reaction of 1,4-phenyl-diamine (para-phenylenediamine) and terephthaloyl chloride to produce an aramid
Kevlar (para-aramid) [2] is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora.Developed by Stephanie Kwolek at DuPont in 1965, [3] [2] [4] the high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tires.
The polymer is closely related to Teijin Aramids's Twaron or DuPont's Kevlar. Technora is derived from two different diamines, 3,4'-ODA and PPD, whereas Twaron is derived from PPD alone. Because only one amide solvent is used in this very straightforward procedure, spinning can be completed immediately after polymer synthesis.
Fibre-reinforced plastic (FRP; also called fibre-reinforced polymer, or in American English fiber) is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass (in fibreglass ), carbon (in carbon-fibre-reinforced polymer ), aramid , or basalt .