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Kevlar
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. Kevlar has many applications, ranging from bicycle tires and racing sails to bulletproof vests, due to its high tensile strength-to-weight ratio; by this measure it is five times stronger than steel. It is also used to make modern marching drumheads that withstand high impact, and for mooring lines and other underwater applications. A similar fiber, Twaron, with the same chemical structure was developed by Akzo in the 1970s. Commercial production started in 1986, and Twaron is manufactured by Teijin Aramid. History Poly-paraphenylene terephthalamide (K29) – bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synthetic Fiber
Synthetic fibers or synthetic fibres (in British English; see spelling differences) are fibers made by humans through chemical synthesis, as opposed to natural fibers that are directly derived from living organisms, such as plants like cotton or fur from animals. They are the result of extensive research by scientists to replicate naturally occurring animal and plant fibers. In general, synthetic fibers are created by extruding fiber-forming materials through spinnerets, forming a fiber. These are called synthetic or artificial fibers. The word polymer comes from a Greek prefix "poly" which means "many" and suffix "mer" which means "single units". (Note: each single unit of a polymer is called a monomer). The first synthetic fibres Nylon was the first commercially successful synthetic thermoplastic polymer. DuPont began its research project in 1927. The first nylon, nylon 66, was synthesized on February 28, 1935, by Wallace Hume Carothers at DuPont's research facili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephanie Kwolek Women In Chemistry From Video
Stephanie is a female name that comes from the Greek name Στέφανος (Stephanos) meaning "crown, wreath, garland". The male form is Stephen. Forms of Stephanie in other languages include the German "Stefanie", the Italian, Czech, Polish, and Russian " Stefania", the Portuguese ''Estefânia'' (although the use of that version has become rare, and both the English and French versions are the ones commonly used), and the Spanish ''Estefanía''. The form Stéphanie is from the French language, but Stephanie is now widely used both in English- and Spanish-speaking cultures. Given names Royalty *Stephanie, Queen of Navarre (died after 1066), Queen consort of king García Sánchez III of Navarre * Stephanie of Castile (died 1 July 1180), illegitimate daughter of Alfonso VII of León and Castile * Stephanie of Milly, Lady of Oultrejordain (died 1197), an influential figure in the Kingdom of Jerusalem * Stephanie of Milly, Lady of Gibelet, an influential figure in the Kingd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylene
In organic chemistry, the phenylene group () is based on a di-substituted benzene ring ( arylene). For example, poly(''p''-phenylene) is a polymer built up from ''para''-phenylene repeating units.p. C-9, Section 11.6, Handbook of Chemistry and Physics, 62nd Edition, 1981-1982, CRC Press The phenylene group has three structural isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a compound is a compound that contains the same number and type of atoms, but with a different connectivity (i.e. arrangement of bonds) between them. The ...s, based on which hydrogens are substituted: ''para''-phenylene, ''meta''-phenylene, and ''ortho''-phenylene. References Arenediyl groups {{Aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
Chemical synthesis (chemical combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation under certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the '' reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that could be produced based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly(p-phenylenterephthalamid)-Synthese
Poly, from the Greek πολύς meaning "many" or "much", may refer to: Businesses * China Poly Group Corporation, a Chinese business group, and its subsidiaries: ** Poly Property, a Hong Kong incorporated Chinese property developer ** Poly Real Estate, a Chinese real estate developer ** Poly Technologies, a defense manufacturing company * Poly (company), formerly Polycom, an American communications technology company People * Poly (footballer) (1906-1986), full name Policarpo Ribeiro de Oliveira, Brazilian footballer * Natasha Poly (born 1985), stage name of Russian supermodel Natalya Sergeyevna Polevshchikova * Poly Styrene (1957–2011), stage name of British musician Marianne Joan Elliott-Said Polytechnic * Hong Kong Polytechnic University, locally known as Poly * Polytechnic Heights, Fort Worth, Texas, neighborhood locally known as Poly * Polytechnic Institute of NYU (now New York University Tandon School of Engineering), locally known as Poly * ''The Rensselaer Polytec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacob Lahijani
Jacob, later known as Israel, is a Patriarchs (Bible), Hebrew patriarch of the Abrahamic religions. He first appears in the Torah, where he is described in the Book of Genesis as a son of Isaac and Rebecca. Accordingly, alongside his older fraternal twin brother Esau, Jacob's paternal grandparents are Abraham and Sarah and his maternal grandfather is Bethuel, whose wife is not mentioned. He is said to have bought Esau's birthright and, with his mother's help, deceived his aging father to bless him instead of Esau. Then, following a severe drought in his homeland Canaan, Jacob and his descendants migrated to neighbouring Biblical Egypt, Egypt through the efforts of his son Joseph (Genesis), Joseph, who had become a confidant of the Pharaohs in the Bible, pharaoh. After dying in Egypt at the age of 147, he is supposed to have been buried in the Cave of Machpelah in Hebron. Per the Hebrew Bible, Jacob's progeny were beget by four women: his wives (and maternal cousins) Leah and Rach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flak Jacket
The two components of an obsolete British military flak vest. On the left, the ballistic_nylon.html" ;"title="nylon vest. On the right, the 12 layers of ballistic nylon">nylon vest. On the right, the 12 layers of ballistic nylon that provide the actual protection A flak jacket or flak vest is a form of body armor. A flak jacket is designed to provide protection from Fragmentation (weaponry), case fragments ("frag") from high explosive weaponry, such as anti-aircraft artillery ("flak" is a German contraction for , "aircraft-defense gun"), grenade fragments, very small pellets used in shotguns such as the "Birdshot", and other lower-velocity projectiles. It is not designed to protect against bullets fired from most small arms such as rifles or handguns. However flak jackets are able to sustain certain gunshots, depending on the angle at which the shot was fired (an oblique angle for example), the caliber of the bullet, the speed of the projectile and the range from which the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lester Shubin
Lester D. Shubin (September 27, 1925 – November 20, 2009) was an American research chemist who developed Kevlar for the use in ballistic vests. Kevlar's use in ballistic vests was later expanded for use in all types of personal armor. Life Shubin was born in Philadelphia, Pennsylvania, and graduated from South Philadelphia High School in 1943. He served in the U.S. Army within France and Germany during World War II. He was among the troops that liberated the Dachau concentration camp. "He didn't talk about it until the last few years," his son Harry Shubin said. "It completely changed his life. He didn't follow rules if they didn't make sense to him. And he'd explain his thinking to you, and by the time he was done, you agreed." After the war, Shubin worked as a chemist and joined the U.S. Department of Justice in 1971. Shubin worked for many years at the National Institute of Justice ("NIJ"), the federal agency designated with research and development in the field of law enfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer Chemistry
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 chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules. However, polymer chemistry is typically related to synthetic and organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, such as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.Hans-Heinrich Moretto, Manfred Schulz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nylon
Nylon is a family of synthetic polymers characterised by amide linkages, typically connecting aliphatic or Polyamide#Classification, semi-aromatic groups. Nylons are generally brownish in color and can possess a soft texture, with some varieties exhibiting a silk-like appearance. As Thermoplastic, thermoplastics, nylons can be melt-processed into fibres, Thin film, films, and diverse shapes. The properties of nylons are often modified by blending with a variety of additives. Numerous types of nylon are available. One family, designated nylon-XY, is derived from diamines and dicarboxylic acids of carbon chain lengths X and Y, respectively. An important example is nylon-6,6 (). Another family, designated nylon-Z, is derived from amino acid, aminocarboxylic acids with carbon chain length Z. An example is nylon-[6]. Nylon polymers have extensive commercial applications, including uses in textiles and fibres (such as apparel, flooring and rubber reinforcement), molded components fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinneret (polymers)
A spinneret is a device used to extrude a polymer solution or polymer melt to form fibers. Streams of viscous polymer exit via the spinneret into air or liquid leading to a phase inversion which allows the polymer to solidify. The individual polymer chains tend to align in the fiber because of viscous flow. This airstream liquid-to-fiber formation process is similar to the production process for cotton candy. The fiber production process is generally referred to as "spinning". Depending on the type of spinneret used, either solid or hollow fibers can be formed. Spinnerets are also used for electrospinning and electrospraying applications. They are sometimes called ''coaxial needles,'' or ''coaxial emitters.'' Spinnerets are usually made of metals with melting points too low to withstand the heating processes employed in industrial metallurgy, and thus are generally not used to form metallic fibers. See also * Electrospinning * Hollow fiber membrane * Spinning (polyme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup has a higher viscosity than water. Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per metre squared, or pascal-seconds. Viscosity quantifies the internal friction, frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's center line than near its walls. Experiments show that some stress (physics), stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
