| 释义 |
polymer Chem.|ˈpɒlɪmə(r)|
[mod. (Berzelius, 1830) f. Gr. πολυµερ-ής having many parts, manifold, f. πολυ-, poly- + µέρος part, share; so mod.F. polymère adj. See isomer.]
1. A substance polymeric with another; any one of a series of polymeric compounds. In mod. use, any substance which has a molecular structure built up largely or completely from a number (freq. very large) of similar polyatomic units bonded together.
The repeating units are often molecules of a single compound, but polymers may also result from combination of two or more different constituents; in either case linking of units may be accompanied by elimination of small molecules, and the formula and molecular weight of the polymer are not necessarily exact multiples of those of any component monomer. Also, esp. in contexts of Applied Chemistry, the use of the term is sometimes restricted to cases where the number of units in the structure is large.
1866Roscoe Elem. Chem. 314 Cyanuric Acid... This polymer of cyanic acid is a solid crystalline substance formed on heating urea. 1889J. Croll Stellar Evol. 95 The bodies thus formed are known as polymers. 1929W. H. Carothers in Jrnl. Amer. Chem. Soc. LI. 2548 Whatever the term polymer may mean now, it does not mean precisely what Berzelius intended, and the conditions which he set up are not sufficient to define it. Ibid. 2549 Two types of polymers may be distinguished... (1) Addition or A polymers. The molecular formula of the monomer is identical with that of the structural unit... (2) Condensation or C polymers: the molecular formula of the monomer differs from that of the structural unit. 1935C. Ellis Chem. Synthetic Resins I. iv. 53 In a condensation reaction, the polymer is no longer a multiple of the monomer as in the case of the addition polymer. 1958Times 21 Nov. 5/6 All of them are formed by the joining together of simpler molecules; they are therefore polymers, as are plastics and synthetic fibres. 1967Margerison & East Introd. Polymer Chem. iii. 131 As the conversion of the monomers into polymer proceeds, the number of possible ways in which the monomers may add on to the growing polymer increases rapidly. 1969Times 3 July 7/7 The substance is a polymer of ordinary water molecules linked together by an unusual kind of chemical bond. 1973Nature 6 Apr. 420/1 Natural rubber is still the preferred polymer for many high performance applications. 1974Sci. Amer. Mar. 66/3 Glass is an inorganic polymer made up of rings and chains of repeating silicate units. 1974D. M. Adams Inorg. Solids vii. 239 The most stable polymers for other metals are M6O8-19 (M = Nb, Ta), Mo7O6-24, Mo8O4-26 and HW6O5-21 . 1978Prospects for Polymers (Shell Internat. Petroleum Co.) 1 Not all polymers are man-made: wool, rubber, cotton and silk are examples of natural polymers.
2. attrib. and Comb., as polymer chemistry, that branch of chemistry concerned with the preparation and properties of polymers; so polymer chemist.
1929Industr. & Engin. Chem. Feb. 131/1 Beyond certain degrees of polymerization x-ray methods do not longer enable estimations of polymer length. 1933Ibid. Feb. 132/1 Development of the best binder—be it resin or another member of the polymer family—is the next step. 1948Science 19 Nov. 545/2 In recent years polymer chemists have shown how it is possible to synthesize compounds of high molecular weight..from known compounds (monomers) of low molecular weight. 1950Nature 22 Apr. 634/1 (heading) Polymer chemistry as applied to plastics. 1953Endeavour Apr. 92/1 In terms of polymer-chemistry concepts, the molecular shape is changed by the electrostatic field. 1966C. R. Tottle Sci. Engin. Materials p. vi, An enormous quantity of synthetic polymer materials has replaced much of the metal in the domestic kitchen, leather, wool, and cotton in furnishings, and natural rubber, wood, and metal in vehicles, prime movers. 1967Margerison & East Introd. Polymer Chem. i. 16 However, in the case of a real polymer chain, the finite size of the backbone carbon atoms and the substituents cannot be neglected. Ibid. 22 Polymer molecules in the pure liquid state can easily be pictured in the terms used to describe concentrated solutions. 1975Nature 31 July 443/3 For those wishing to get a feel for what is going on in a selection of other areas of polymer science this volume will provide much of interest. |