| 单词 | bakelite | |||
| 释义 | BakeliteBa·ke·liteB0032100 (bā′kə-līt′, bāk′līt′)Bakelite(ˈbeɪkəˌlaɪt)Ba•ke•lite(ˈbeɪ kəˌlaɪt, ˈbeɪk laɪt)Trademark.
BakeliteBakelite(bā`kəlīt) [for its inventor, L. H. BaekelandBaekeland, Leo Hendrik, 1863–1944, American chemist, b. Belgium, grad. Univ. of Ghent, 1882. In 1889 he emigrated to the United States. He founded (1893) and conducted, until 1899, when he sold the rights to Eastman, a company for producing a photographic paper of his own ..... Click the link for more information. ], synthetic thermosetting resinresin, any of a class of amorphous solids or semisolids. Resins are found in nature and are chiefly of vegetable origin. They are typically light yellow to dark brown in color; tasteless; odorless or faintly aromatic; translucent or transparent; brittle, fracturing like glass; ..... Click the link for more information. . It has been widely used both alone, to form whole objects, and in combination with other materials, as a laminate or a surface coating. It was used as a substitute for hard rubber, amber, or celluloid; for insulating electrical apparatus (since it is a nonconductor); and for the manufacture of certain machinery gears, phonograph records, and many other articles useful and ornamental and as diverse in character as buttons, billiard balls, pipestems, and umbrella handles. Bakelite is a condensation polymerpolymer , 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, ..... Click the link for more information. of formaldehydeformaldehyde , HCHO, the simplest aldehyde. It melts at −92°C;, boils at −21°C;, and is soluble in water, alcohol, and ether; at STP, it is a flammable, poisonous, colorless gas with a suffocating odor. ..... Click the link for more information. and phenolphenol , C6H5OH, a colorless, crystalline solid that melts at about 41°C;, boils at 182°C;, and is soluble in ethanol and ether and somewhat soluble in water. An aromatic alcohol, it exhibits weak acidic properties and is corrosive and poisonous. ..... Click the link for more information. . In practice, the phenol and formaldehyde are first polymerized to a small extent by using the proper choice of catalyst and temperature. The resulting prepolymer, called a resol, is a low-melting, soluble material, which can then be combined with a filler (usually cotton linters or wood fibers) and a pigment and heated under pressure in a mold to yield an object of the desired shape. The pure resin is colorless or amber-colored and very brittle; the various fillers and other additives give it the desired properties depending on its application. Heating of the prepolymer results in extensive cross-links between the polymer chains, resulting in a tightly bound three-dimensional network. A Bakelite-type resin can also be formed using furfuralfurfural or furfuraldehyde [Lat.,=bran], C4H3OCHO, viscous, colorless liquid that has a pleasant aromatic odor; upon exposure to air it turns dark brown or black. It boils at about 160°C;. ..... Click the link for more information. in place of the formaldehyde. BakeliteBakelite
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Bakelite - a thermosetting plastic used as electric insulators and for making plastic ware and telephone receivers etc.