Coal Tar Pitch Modification Methods: Effect of Surfactant Substances and Carbon Additives on Binder Properties

Resumo

The effect of modifying coal tar pitch with different additives is studied; surfactant substances (SAS), carbon-containing modifiers, and high-temperature binder additives. Using SAS a reduction is observed in viscosity for a system of original pitch–modifier, and with a concentration of 7 wt.% it is most effective to use oleic acid, but with a concentration of 10 wt.% to use myristic acid. In both cases viscosity is reduced by almost a factor of ten with respect to original pitch viscosity. In the case of carbon-containing additives viscosity increases, the same as with use of a high-temperature binder. The effect of modifiers on coke residue yield is studied. On modifying pitch with SAS the reduction in coke residue obeys an additivity rule, which is explained by total removal of SAS from a pitch–modifier system. With use of carbon-containing modifiers and high-temperature binder the coke residue also increases by an additive rule.