Grafting onto Carbon Black Having Few Functional Groups (9 th Report) : Friedel-Crafts Reaction of Polymers with Polycondensed Aromatic Rings of Carbon Black Surface

Abstract

The grafting of polymers onto carbon black by Friedel-Crafts reaction of acyl chloride-capped polymers with polycondensed aromatic rings of the surface was investigated. Acyl chloride-capped polymers (PPG-COCl) were prepared by the reaction of diol-type poly (propylene oxide) (PPG) with car-boxylic acid dichloride, such as succinyl dichloride, adipoyl dichloride, and phthaloyl dichloride. It was found that by the reaction of carbon black with PPG-COCl in the presence of AlCl₃ at 60°C, PPG was successfully grafted onto carbon black surface. On the contrary, by the treatment of carbon black with PPG in the presence of AlCl₃ and by the treatment with PPG-COCl in the absence of AlCl₃, the grafting of PPG onto carbon black surface was rarely observed. Based on the above results, it was concluded that the grafting of PPG onto the carbon black surface proceeded by Friedel-Crafts reaction of PPG-COCl with polycondensed aromatic rings of carbon black surface. The percentage of grafting increased with increasing molecular weight of PPG-COCl, but the number of grafted PPG chain decreased. The effects of reaction temperature and catalyst on the grafting reaction were also, discussed. Furthermore, PPG-graf ted carbon black gave a stable colloidal dispersion in a good solo-vent for PPG.