Surface Modification of Carbon Black by Oleic Acid for Miniemulsion Polymerization of Styrene

To carry out miniemulsion polymerization of styrene in the presence of carbon black, carbon black was hydroxylated using potassium permanganate with the aid of a phase transfer catalyst, tetrabutyl ammonium bromide (TBABr). The hydroxylated carbon black was further reacted with oleic acid. The surface modification of carbon black with oleic acid was confirmed by FTIR, XPS, and TEM. The oleic acid-coated carbon black was successfully microencapsulated by polystyrene using miniemulsion polymerization. Polymerization failed when pristine carbon black was used. However, satisfactory conversion (> 96%) was achieved using the oleic acid-modified carbon black. The existence of a polystyrene layer was confirmed by TEM. In contrast the pristine carbon black, the oleic acid-coated carbon black did not act as a radical scavenger during polymerization.