Ebonite

ebonite [ēb·ə‚nīt]

(materials)

hard rubber

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Ebonite 

a product resulting from the vulcanization of rubber with large quantities of sulfur, about 30 to 50 percent per mass of rubber. Ebonites are hard materials and, unlike “soft” rubbers, display no high-elastic properties at ordinary temperatures. They lend themselves readily to mechanical processing, are nonhygroscopic and impermeable to gas, and are resistant to the action of solutions of acids, bases, salts, plant oils, and animal fats. They are decomposed by strong oxidizing agents and by aromatic and chlorinated hydrocarbons. Ebonites have a density of 1.15–1.68 g/cm³, a Young’s modulus of 2–3 giganewtons/m² (20 × 10³ to 30 × 10³ kilograms-force/cm²), a tensile strength of 52–67 meganewtons/m² (520–670 kilograms-force/cm²), and a volumetric resistivity of 1–10 teraohm-m (10¹⁴–10¹⁵ ohm · cm).

Ebonites are used to manufacture electric insulating components of devices and to rubberize various vessels used for corrosive liquids. In many areas of technology, ebonites are being replaced by plastics, which have superior dielectric properties and chemical stability.

REFERENCE

Entsiklopediia polimerov, vol. 3. Moscow, 1977.