Acetylene Black
Acetylene black is a general term for a group of carbon black materials produced from the partial oxidation of acetylene in an oxygen-containing atmosphere. It is used mostly in rubber products and synthetic fibers due to its low cost, high structure maintenance and excellent absorption properties.
History
The development of acetylene black began in the late 19th century when acetylene gas, a product of the reaction between calcium carbide and water, was first used as a fuel source in lamps. In 1895, researchers at the German firm of Hoechst discovered that by burning acetylene in a fairly oxygen-rich atmosphere, they could produce a black solid residue.
Structure
The molecular structure of acetylene black is similar to that of graphite, but with a higher percentage of impurities than graphite. Acetylene black is composed of small, spherical particles which are interconnected to form a network structure. The particles are highly porous, with a large pores-to-mass ratio.
Production
Acetylene black is produced from a highly exothermic reaction between acetylene and oxygen. The acetylene is heated until it begins burning and a mixture of oxygen and carbon dioxide is injected in small increments. The resultant heat causes the volatile reaction products to combine into carbon particles. The reaction is stopped before the small particles can agglomerate and form larger particles.
Uses
Acetylene black is used in rubber, elastomers, compounds, and tires due to its low unit cost, high structure maintenance and high absorption properties. It contributes excellent abrasion resistance and physical reinforcement to compounds and is also used in synthetic fiber manufacturing. In battery manufacture, it is used to increase the conductivity of the positive electrode material, allowing greater energy output and longer shelf life.
Specifications
Acetylene black is produced in various grades based on particle size, specific surface area, surface structure and purity. Specifications for acetylene black are outlined in GB/T3782-93. This standard defines acetylene black in terms of specific surface area, pH value, water content, ash content, granule size and apparent density.
Conclusion
Acetylene black is a low cost carbon black material produced from the partial oxidation of acetylene in an oxygen-rich atmosphere. It is characterized by a highly porous network structure and is used in rubber and elastomers products and synthetic fibers due to its low unit cost and high structure maintenance. Specifications for acetylene black are outlined in GB/T3782-93.
