AbstractIt was found that an ion radical complex is formed by the reaction of carbon black with an alkali metal (Li, Na, K) in tetrahydrofuran. The graft copolymerization of styrene with carbon black was carried out using the ion radical complexes as initiator, and free polystyrene and carbon black‐polystyrene graft copolymer were obtained. The identification of the graft copolymer with carbon black was carried out by fractionation and thermal degradation. The initiation activity of the alkali metals increased in the order Li展开▼