INTRODUCTION OF CATIONIC GROUPS ONTO CARBON BLACK SURFACE AND THEIR DISPERSIBILITY INWATER

Imidazoline hydrochloride groups were successfully introduced onto carbon black surface by the treatment of imidazoline groups, which were introduced by the trapping of 2-(2-imidazolin-2-yl)propane radicals formed by the thermal decomposition of 2,2ʹ-azobis[2-(2-imidazolin-2-yl)propane] (AIP) with hydrochloric acid. In addition, amidine hydrochloride groups were introduced onto carbon black surface by the radical trapping of 2methylpropionamidine dihydrochloride radicals formed by the thermal decomposition of 2,2ʹ-azobis(2-methylpropionamidine) dihydrochloride (AMPAD). The content of imidazoline hydrochloride and amidine hydrochloride groups introduced onto carbon black was determined to be 0.6 mmol/g and 0.7 mmol/g, respectively. The mean particle size of AlP/HC1-treated and AMPAD-treated carbon black was determined to be 31 nm and 16 nm, respectively, by dynamic light scattering method. It was found that the surface of carbon black turned from hydrophobic to hydrophilic by the introduction of cationic moieties and gave a very stable colloidal dispersion in neutral and acidic water at room temperature.