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Polysilazane
Polysilazanes are polymers in which silicon and nitrogen atoms alternate to form the basic backbone. Since each silicon atom is bound to two separate nitrogen atoms and each nitrogen atom to two silicon atoms, both chains and rings of the formula ^1R^2Si-NR^3\mathit occur. R^1-R^3 can be hydrogen atoms or organic substituents. If all substituents R are H atoms, the polymer is designated as Perhydropolysilazane, Polyperhydridosilazane, or Inorganic Polysilazane ( 2Si–NHsub>). If hydrocarbon substituents are bound to the silicon atoms, the polymers are designated as Organopolysilazanes. Molecularly, polysilazanes ^1R^2Si-NH\mathit are isoelectronic with and close relatives to Polysiloxanes ^1R^2Si-O\mathit (silicones). History The synthesis of polyorganosilazanes was first described in 1964 by Krüger and Rochow. By reacting ammonia with chlorosilanes (ammonolysis), trimeric or tetrameric cyclosilazanes were formed initially and further reacted at high temperatures with a catalys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PHPS Molecular Structure 6MPix
Polysilazanes are polymers in which silicon and nitrogen atoms alternate to form the basic backbone. Since each silicon atom is bound to two separate nitrogen atoms and each nitrogen atom to two silicon atoms, both chains and rings of the formula ^1R^2Si-NR^3\mathit occur. R^1-R^3 can be hydrogen atoms or organic substituents. If all substituents R are H atoms, the polymer is designated as Perhydropolysilazane, Polyperhydridosilazane, or Inorganic Polysilazane ( 2Si–NHsub>). If hydrocarbon substituents are bound to the silicon atoms, the polymers are designated as Organopolysilazanes. Molecularly, polysilazanes ^1R^2Si-NH\mathit are isoelectronic with and close relatives to Polysiloxanes ^1R^2Si-O\mathit (silicones). History The synthesis of polyorganosilazanes was first described in 1964 by Krüger and Rochow. By reacting ammonia with chlorosilanes (ammonolysis), trimeric or tetrameric cyclosilazanes were formed initially and further reacted at high temperatures with a catalys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore International
Commodore International (other names include Commodore International Limited) was an American home computer and electronics manufacturer founded by Jack Tramiel. Commodore International (CI), along with its subsidiary Commodore Business Machines (CBM), was a significant participant in the development of the home personal computer industry in the 1970s, 1980s and early 1990s. The company developed and marketed the world's best-selling computer, the Commodore 64 (1982), and released its Amiga computer line in July 1985. With quarterly sales ending 1983 of $ (equivalent to $ in ), Commodore was one of the world's largest personal computer manufacturers. History Founding and early years Commodore co-founders Jack Tramiel and Manfred Kapp met in the early 1950s while both employed by the Ace Typewriter Repair Company in New York City. In 1954, they formed a partnership to sell used and reconditioned typewriters and used their profits to purchase the Singer Typewriter Company. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, Carbon-12, C and Carbon-13, C being stable, while Carbon-14, C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the Timeline of chemical element discoveries#Ancient discoveries, few elements known since antiquity. Carbon is the 15th Abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the Abundance of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
