Some Properties of Carbon Black

Abstract

Abstract The term “carbon black” will be used in this paper to include all the varieties of moderately pure carbon existing in the form of soot. So far as the rubber industry is concerned, four distinct types of carbon black are in general use, as follows: (1) Gas Black.—Sometimes itself called carbon black, made by the incomplete combustion of natural gas, the principal component of which is methane. The flames of burning gas impinge on metal surfaces, on which the black is deposited. (Cf. Neal and Perrott, Bull. No. 192, United States Bureau of Mines, 1922.) (2) Acetylene Black.—Produced by the explosive combustion of purified acetylene in closed chambers. (3) Lamp Black.—Obtained by incomplete combustion of fats, oils, tars, etc. Unlike the gas black particles, which are removed from the interior of the flame, those of lamp black pass through the outer layer before deposition. (Twiss, India Rubber J., 65, 607, 651, 393 (1923)). (4) Thermatomic Black.—Made by thermal decomposition of natural gas out of contact with air. The difference in physical properties of these blacks depends largely on differences in heat treatment during manufacture. They are arranged above in order of the size of the individual particles, those of gas black easily averaging the smallest.