Polymer, High

Name:
Polymer, High
Detailed information:
An organic macromolecule composed of a large number of monomers. The molecular weight may range from 5000 into the millions (for some polypeptides). Natural high polymers are exemplified by cellulose (C₆H₁₀O)_n and rubber (C₅H₈)_n. Proteins are natural high-polymer combinations of amino acid monomers. The dividing line between low and high polymers is considered to be in the neighborhood of 5000 to 6000 mw.Synthetic high polymers (or “synthetic resins”) include a wide variety of materials having properties ranging from hard and brittle to soft and elastic. Addition of such modifying agents as fillers, colorants, etc. yields an almost infinite number of products collectively called plastics. High polymers are the primary constituents of synthetic fibers, coating materials (paints and varnishes), adhesives, sealants, etc. Polymers having special elastic properties are called rubbers, or elastomers.Synthetic polymers in general can be classified: (1) by thermal behavior, i.e., thermoplastic and thermosetting; (2) by chemical nature, i.e., amino, alkyd, acrylic, vinyl, phenolic, cellulosic, epoxy, urethane, siloxane, etc.; and (3) by molecular structure, i.e., atactic, stereospecific, linear, cross-linked, block, graft, ladder, etc. Copolymers are products made by combining two or more polymers in one reaction (styrene-butadiene).See Cross-linking; Block Polymer; Epitaxy; Homopolymer; Plastic.