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polymer
polymer , chemical compound with high molecular weight consisting of a number of structural units linked together by covalent bonds (see chemical bond ). The simple molecules that may become structural units are themselves called monomers; two monomers combine to form a dimer, and three monomers, a...
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latex
latex emulsion of a polymer (e.g., rubber ) in water (see colloid ). Natural latexes are produced by a number of plants, are usually white in color, and often contain, in addition to rubber, various gums, oils, and waxes. Balata, caoutchouc, chicle, and gutta-percha are produced from natural late...
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vinyl plastics
vinyl plastics group of thermoplastics used in molded products, flexible tubing, material for raincoats, and laminated safety glass. Vinyl plastics are polymers and copolymers of vinyl derivatives (i.e., derivatives of ethylene, H 2 C[symbol]CH 2 ), e.g., vinyl chloride (H 2 C=CHCl) and vinyl a...
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thermoplastics
thermoplastics materials that soften or melt when heated and harden when cooled. Thermoplastic polymers consist of long polymer molecules that are not linked to each other. i.e., have no cross-links. They are often supplied as granules and heated to permit fabrication by methods such as molding or ...
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macromolecule
macromolecule term that may refer either to a crystal such as a diamond, in which the atoms are identical and held by covalent bonds (see chemical bond ) of equal strength, or to one of the units that compose a polymer . Macromolecules such as proteins and nucleic acids are vital to the functio...
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gutta-percha
gutta-percha , natural latex obtained from Palaquium gutta and several other evergreen trees of East Asia. The latex, collected by felling or girdling the tree, is allowed to coagulate and is then washed, purified, and molded into bricks for shipping. Like caoutchouc , gutta-percha is a polyter...
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melamine
melamine , common name for 2,4,6-triamino-1,3,5-triazine. Melamine is a trimer (see polymer ) of cyanamide, H 2 NC[triple bond]N, and is synthesized from calcium carbide. It condenses with formaldehyde to give a thermosetting resin . Melamine resins have many uses, including the manufacture of pla...
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polyethylene
polyethylene , widely used plastic . It is a polymer of ethylene , CH 2 [symbol]CH 2 , having the formula (-CH 2 -CH 2 -) n , and is produced at high pressures and temperatures in the presence of any one of several catalysts , depending on the desired properties for the finished product. Polyet...
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polypropylene
polypropylene , plastic noted for its light weight, being less dense than water; it is a polymer of propylene. It resists moisture, oils, and solvents. Since its melting point is 121°C (250°F), it is used in the manufacture of objects that are sterilized in the course of their use. Polyp...
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polyvinyl chloride
polyvinyl chloride (PVC), thermoplastic that is a polymer of vinyl chloride. Resins of polyvinyl chloride are hard, but with the addition of plasticizers a flexible, elastic plastic can be made. This plastic has found extensive use as an electrical insulator for wires and cables. Cloth and pape...
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