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Methacrylamide
Methacrylamide is the organic compound with the formula CH2=C(CH3)C(O)NH2. A colorless or white solid, it is a monomer for the production of polymers and copolymers, some of which are used in hydrogels. Methacrylamide is also a precursor (chemistry), precursor of methyl methacrylate. References {{organic-compound-stub Acrylamides Monomers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Methacrylate
Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. This colorless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA). Production and properties Given the scale of production, many methods have been developed starting from diverse two- to four-carbon precursors.. Two principal routes appear to be commonly practiced. Cyanohydrin route The compound is manufactured by several methods, the principal one being the acetone cyanohydrin (ACH) route. ACH is produced by condensation of acetone and hydrogen cyanide. The cyanohydrin is hydrolyzed in the presence of sulfuric acid to a sulfate ester of the methacrylamide. Methanolysis of this ester gives ammonium bisulfate and MMA. Although widely used, the ACH route coproduces substantial amounts of ammonium sulfate. :(CH3)2CO + HCN → (CH3)2C(OH)CN :(CH3)2C(OH)CN + H2SO4 → (CH3)2C(OSO3H)C(O)NH2. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymers
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'', meani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copolymer
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are sometimes called ''bipolymers''. Those obtained from three and four monomers are called ''terpolymers'' and ''quaterpolymers'', respectively. Copolymers can be characterized by a variety of techniques such as NMR spectroscopy and size-exclusion chromatography to determine the molecular size, weight, properties, and composition of the material. Commercial copolymers include acrylonitrile butadiene styrene (ABS), styrene/butadiene co-polymer (SBR), nitrile rubber, styrene-acrylonitrile, styrene-isoprene-styrene (SIS) and ethylene-vinyl acetate, all of which are formed by chain-growth polymerization. Another production mechanism is step-growth polymerization, which is used to produce the nylon-12/6/66 copolymer of nylon 12, nylon 6 and nylon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogel
A hydrogel is a crosslinked hydrophilic polymer that does not dissolve in water. They are highly absorbent yet maintain well defined structures. These properties underpin several applications, especially in the biomedical area. Many hydrogels are synthetic, but some are derived from nature. The term 'hydrogel' was coined in 1894. Chemistry Classification The crosslinks which bond the polymers of a hydrogel fall under two general categories: physical and chemical. Chemical hydrogels have covalent cross-linking bonds, whereas physical hydrogels have non-covalent bonds. Chemical hydrogels result in strong irreversible gels due to the covalent bonding, and they may also possess harmful properties which makes them unfavourable for medical applications. Physical hydrogels on the other hand have high biocompatibility, aren’t toxic, and are also easily reversible, by simply changing an external stimulus such as pH or temperature; thus they are favourable for use in medical applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precursor (chemistry)
In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry, the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway, such as a protein precursor. Illicit drug precursors In 1988, the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances introduced detailed provisions and requirements relating the control of precursors used to produce drugs of abuse. In Europe the Regulation (EC) No. 273/2004 of the European Parliament and of the Council on drug precursors was adopted on 11 February 2004. ( European law on drug precursors) Illicit explosives precursors On January 15, 2013, the Regulation (EU) No. 98/2013 of the European Parliament and of the Council on the marketing and use of explosives precursors was adopted. The Regulation harmonises rules across Europe on the making available, introduction, possession and u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylamides
Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH2=CHC(O)NH2. It is a white odorless solid, soluble in water and several organic solvents. From the chemistry perspective, acrylamide is a vinyl-substituted primary amide (CONH2). It is produced industrially mainly as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and flocculation agents. Acrylamide forms in burnt areas of food, particularly starchy foods like potatoes, when cooked with high heat, above . Acrylamide is highly toxic, linked to cancer in animal testing though not likely to be carcinogenic for humans, but its main derivative polyacrylamide is nontoxic. The possibility that this innocuous polymer contains traces of its hazardous precursor has long attracted attention. Because acrylamide is volatile and hazardous, it is mainly handled as an aqueous solution. Production Acrylamide can be prepared by the hydration of acrylonitrile: :CH2=CHCN + H2O → C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
