Ebonite

EBONIT - firm product of curing of natural or synthetic rubber large amounts of sulfur. Well gives in to machining, it is gas-tight, resistant to effect of acids and alkalis; possesses electric insulation properties. It is applied in production of electric insulation details, accumulator boxes; it is gradually replaced with plastic. Plotn. ebonite of 1,15-1,68 g/cm3; show vysokoelastich. the sv-va is above 55 °C; exceed usual rubbers on fur. durabilities (elastic modulus of 2-3 GPA, 50-70 MPas) and dielektrich. to sv-you (1014-1015 Ohms-cm). Ebonite is non-hygroscopic, gas-tight, easily gives in fur. to processing, possess high adhesion to metal. Racks to alifatich. to hydrocarbons (at bang to 100 °C), raises. and to animal fats, solutions of alkalis, salts, inoxidizable to - t, collapse in oxidizers, aromatich. and chlorinated hydrocarbons.

Some properties of ebonite

Density, g/cm3	≥1, 14
Breaking strength, kg/cm2	700
Specific elongation at gap, %	3
Heat conductivity, kal / sec. see hail	39. 10-5
Water absorption, % (on air)	0, 005 — 0, 02
Dielectric permeability (1000 Hz)	2, 82
Specific volume electric resistivity, ohm. cm	(2, 6 — 8, 4). 1015
Electric strength, kV/mm	~ 20
Tangent of dielectric loss angle (1000 Hz)	5, 1. 10-3

Ebonite well gives in to machining; it is non-hygroscopic, does not adsorb gases, it is resistant to effect of acids and alkalis, bulks up in carbon sulfur and oil products, it is dissolved in paraffin at temperatures above 300 °C by release of hydrogen sulfide. At action of sunlight owing to oxidation insulating properties of ebonite go down. Ebonite usually between 70 °i 80 °i is softened when cooling again hardens; at temperaturakh200 ° chars without melting.
Ebonite is issued in the form of plates, cores and tubes and is applied to production of electrotechnical products, especially such which have to be resistant to effect of acids (accumulator boxes), and also container for storage of acids and alkalis.
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