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Structure of Twaron and Kevlar.The aromatic rings appear as hexagons. The rings are attached alternately to either two NH groups or two CO groups. The attachment points on each ring are diametrically opposite each other, a characteristic of the structure called para-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.
Composite materials are also becoming more common in the realm of orthopedic surgery, [42] and it is the most common hockey stick material. Carbon composite is a key material in today's launch vehicles and heat shields for the re-entry phase of spacecraft. It is widely used in solar panel substrates, antenna reflectors and yokes of spacecraft.
Ammonium perchlorate ("AP") is an inorganic compound with the formula NH 4 ClO 4.It is a colorless or white solid that is soluble in water. It is a powerful oxidizer.Combined with a fuel, it can be used as a rocket propellant called ammonium perchlorate composite propellant.
The common matrices are polymers (mainly utilized for fibre reinforced plastics). The most common polymer-based composite materials which include carbon fibre, fibreglass and Kevlar, typically involve two parts at least, the resin and the substrate. [5] Asphalt concrete, which is often used in the construction of roads, has a matrix called ...
Polymer chemistry is a sub-discipline of chemistry that focuses on the structures, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry , analytical ...
Dozens of luxury condos, hotels and other buildings in southeast Florida are sinking at a surprising rate, researchers reported in a recent study. The study, led by scientists at the University of ...
The 2014 AP Chemistry exam was the first administration of a redesigned test as a result of a redesigning of the AP Chemistry course. The exam format is now different from the previous years, with 60 multiple choice questions (now with only four answer choices per question), 3 long free response questions, and 4 short free response questions.