Studies on Acetylene Blacks (Part 3) Effects of Secondary Treatments of Acetylne Blacks

Abstract

The relations between the foundamental properties of acetylene blacks produced on some conditions were discussed in detail on the basis of the experimental results in dry cells in my previous papers.
This time the changes of the special properties of acetylene black affected by secondary treatments i. e. pulverizing, heating and compressing have been studied, and the conclusion derived as follows:
(1) The results of rubber tests of acetylene black treated by a ball-mill have shown that decreasing of particle size of acetylene black is not effective to give a good dispersion of black and high degree of reinforcement to rubber compound, for mechanical treatment changes the chain structure of black and perhaps more densely compresses the aggregated particle.
(2) From the results obtained by surface oxidation, of acetylene black, it has been shown that surface area calculated from iodine adsorption value increases along with increasing volatile matter up to 600°C, but both decreases above 600°C. so that there seems to be a definite correlation between the state of oxidized surface and the adsorption property of black.
And it has been found that the pH value of acetylene black gradually increases with increasing temperature, but it is related to the nature of volatile matters, i. e. hydrogen below 600°C and the carbon-oxygen complex CxOy above 600°C.
(3) Acetylene black can be changed to a handy forme by compression of 70% without changing its foundamental properties.