A long or larger molecule consisting of a chain or network of many repeating units, formed by chemically bonding together many identical or similar small molecules called monomers. A polymer is formed by polymerization, the joining of many monomer molecules
A MOLECULE composed of many similar or identical molecular subunits Starch is a polymer of GLUCOSE (Greek polus, manu + meris, part)
Polymers are large molecules of high molecular weight They consist of long, repeated and sometimes, branched chains, built up from small sub-units called monomers Natural polymers include proteins (polymer of amino acids) & cellulose (polymer of sugar molecules) There are many examples of synthetic polymers - e g PVC (a polymer of vinyl acetate), PTFE or Teflon (a polymer of molecules containing fluorine and carbon) PTFE is the basis of the Gortex® membrane There are several polymers (both natural and synthetic) used in Nikwax products to provide water-repellency and durability
A high molecular weight substance, natural or synthetic, which can be represented as a repeated small unit (monomer) A copolymer contains more than one type of monomeric unit
Large molecules built up by the combination of many small molecules through a chemical process called polymerization These molecules can consist of many thousands of atoms in chains or networks of repeating units
A high-molecular-weight organic compound, natural or synthetic, whose structure can be represented by a repeated small unit, the monomer (e g , polyethylene, rubber, cellulose) Synthetic polymers are formed by addition or condensation polymerization of monomer If two or more different monomers are involved, a copolymer is obtained Some polymers are elastomers, some plastics (Plastics Engineering Handbook of the Society of the Plastics Industry, Inc , edited by Michael L Berins, 1991)
A polymer is a chemical compound with large molecules made of many smaller molecules of the same kind. Some polymers exist naturally and others are produced in laboratories and factories. a chemical compound that has a simple structure of large molecules (polymeres , from meros ). Any of a class of natural or synthetic substances composed of macromolecules that are multiples of monomers. The monomers need not all be the same or have the same structure. Polymers may consist of long chains of unbranched or branched monomers or may be cross-linked networks of monomers in two or three dimensions. Their backbones may be flexible or rigid. Some natural inorganic materials (e.g., the minerals diamond, graphite, and feldspar) and certain man-made inorganic materials (e.g., glass) have polymer-like structures. Many important natural materials are organic polymers, including cellulose (from sugar monomers; see polysaccharide), lignin, rubber, proteins (from amino acids), and nucleic acids (from nucleotides). Synthetic organic polymers include many plastics, including polyethylene, the nylons, polyurethanes, polyesters, vinyls (e.g., PVC), and synthetic rubbers. The silicone polymers, with an inorganic backbone of silicon and oxygen atoms and organic side groups, are among the most important mixed organic-inorganic compounds
A substance made of specific repeating chemical units or molecules The term polymer is often used correctly or incorrectly, in place of plastic, rubber or elastomer
A substance made of giant molecules formed by the union of simpler molecules Many water clarifiers are made from organic polymers An example would be polymerized ethylene, called polyethylene
A substance made of many repeating chemical units or molecules The term polymer is often used in place of plastic, rubber or elastomer
substance formed by the linkage (polymerization) of two or more simple, unsaturated molecules ({see unsaturated hydrocarbon}, called monomers), to form a single heavier molecule having the same elements in the same proportions as the original monomers; i e each monomer retains its structural identity A polymer may be liquid or solid; solid polymers may consist of millions of repeated linked units A polymer made from two or more dissimilar monomers is called a copolymer; a copolymer composed of three different types of monomers is a terpolymer Natural rubber and synthetic rubbers are polymers
A molecule with a large molecular weight formed by the linking of 30 to 100,000 (or more) repeating units
(Chemistry) Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule (see monomer) Pulsar: A neutron star with a very fast rotational component and strong magnetic field, which constrains emitting radiation to a cone To be visible from Earth, a pulsar must be oriented such that the cone of emitted radiation intersects Earth Quasar: abbreviation of "quasi-stellar object" Quasars are unusually energetic objects which emit up to 1,000 times as much energy as an entire galaxy, but from a volume about the size of our solar system
Any one of two or more substances related to each other by polymerism; specifically, a substance produced from another substance by chemical polymerization
A large molecule built up by the repetition of small, simple chemical units high molecular-weight substance (from 10 000 to >20,000) formed in an association reaction in which many molecules come together to form one large molecule
A naturally occurring or synthetic substance consisting of giant molecules formed from smaller molecules of the same substance and often having a definite arrangement of the components of the giant molecules
Chemical compound composed of many molecules linked end to end to form a long chain molecule PVC is a polymer
A molecule made up from many similar smaller molecules called monomers Examples include PVC or poly-vinyl chloride and polyester
a large molecule produced by the linkage of smaller subunit molecules called monomers
a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers
A polymer is a natural or synthetic compound of high molecular weight composed of long chains of repeating units, each relatively light and simple
(Otomotiv) A coating that prevents paint from oxidizing, protecting a vehicle from premature fading and rusting. Do-it-yourself polysealants last for from 6 months to a year; professionally applied polyglycotes can last from 2 to 3 years
a polymer, such as PVC, that has been treated with an organic silane; the material is used, in thin films, to remove contaminants from water by pervaporation and also in adhesives
Having the same percentage composition (that is, having the same elements united in the same proportion by weight), but different molecular weights; often used with with; thus, cyanic acid (CNOH), fulminic acid (C2N2O2H2), and cyanuric acid (C3N3O3H3), are polymeric with each other
A chemical reaction in which one or more small molecules combine to form larger molecules A hazardous polymerization is such a reaction that takes place at a rate that releases large amounts of energy If hazardous polymerization can occur with a given material, the MSDS usually will list conditions that could start the reaction andsince the material usually contains a polymerization inhibitorthe length of time during which the inhibitor will be effective
A chemical reaction in which small molecules (monomers) combine to form much larger molecules (polymers) A hazardous polymerization is a reaction that occurs at a fast rate, and releases large amounts of energy Many monomers are hazardous in the liquid and vapor states, but form much less hazardous polymers An example is vinyl chloride monomer, which causes cancer but forms the relatively non-toxic polyvinyl chloride (PVC) plastic
in petroleum refining, polymerization refers to the combination of light, gaseous hydrocarbons, usually olefins, into high-molecular-weight hydrocarbons that are used in manufacturing motor gasoline and aviation fuel The product formed by combining two identical olefin molecules is called a dimer, and by three such molecules, a trimer See polymer
Reaction of two molecules to form a polymer; the length of the polymer chain is specified by the number of repeat units in the chain (degree of polymerization)
Any process in which monomers combine chemically to produce a polymer. The monomer molecules which in the polymer usually number from at least 100 to many thousands may or may not all be the same. In nature, enzymes carry out polymerization under ordinary conditions to form proteins, nucleic acids, and carbohydrate polymers; in industry, the reaction is usually done with a catalyst, often under high pressure or heat. In addition polymerization, monomers are added successively to the reactive ends of a growing polymer molecule, similar to adding links to a chain; during the reactions, no by-products are formed. In condensation polymerization, growth of the polymer advances stepwise monomers having reactive functional groups combine into larger molecules with their own functional groups; each reaction splits off a small molecule, often water, as a by-product
A chemical reaction in which two or more small molecules combine to form larger molecules that contain repeating structural units of the original molecules A hazardous polymerization is the above reaction with an uncontrolled release of energy
A chemical reaction in whch one or more small molecules combine to form larger molecules A hazardous polymerization is such a reaction that takes place at a rate that releases large amounts of energy
A chemical reaction in which one or more small molecules combine to form larger molecules A hazardous polymerization is a reaction that takes place at a rate that releases large amounts of energy If hazardous polymerization can occur with a given material, the MSDS usually will list conditions that could start the reaction and--since the material usually contains a polymerization inhibitor--the length of time during which the inhibitor will be effective
Chemical reaction in which one or more small molecules combine to form larger molecules A hazardous polymerization is such a reaction that takes place at a rate that releases large amounts of energy that can cause fires or explosions or burst containers Materials that can polymerize usually contain inhibitors that can delay the reaction
A chemical reaction in which the molecules of monomers are linked together to form polymers via two principal reaction mechanisms Addition polymerizations proceed by chain growth and most condensation polymerizations through step growth
An undesirable change in the composition of a food fat involving intermolecular agglomeration or clumping of the normal chemical units of fat and its decomposition products into larger and insoluble chemical units
A chemical reaction usually carried out with a catalyst, heat, or light, and often under high pressure, in which a large number of simple molecules combine to form a much larger chain-like macromolecule
Long chains of chemicals, that can be twisted and molded into products Petroleum is heated at very high temperatures to be broken down into polymers and made into plastic
These include the familiar plastic and rubber materials Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements; they have very large molecular structures These materials typically have low densities and may be extremely flexible
These are macromolecular materials constructed from simple molecules (=> Monomers) Both natural fibres and cellulose and synthetic fibres are polymers in their chemical makeup
Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds These compounds often form large macromolecules (e g , polypeptides, proteins, plastics) [MeSH]
Under the Seventh Amendment a polymer is defined as a substance which: Consists of molecules which include a sequence of one or more types of monomer units (the reacted form of a monomer in the structure); Show a molecular weight distribution primarily due to differences in the number of monomer units in the individual molecules; Contain 50% or more by weight of molecules containing a sequence of at least three monomer units covalently bound to at least 1 other monomer unit or reactant; Contain less than 50% by weight of molecules with the same molecular weight A polymer becomes notifiable when it contains 2% or more of a new substance as part of its structure Guidance on Polymer Notification