Abstract
To modify the surface of quinacridone, i.e. 5, 7, 12, 14-tetrahydroquino [2, 3-β] - acridine-7, 14-dione, the grafting of polymers onto the surface by polymerization of vinyl monomers, and its initiation by peroxyester groups introduced beforehand onto the surface, was investigated. The introduction of peroxyester groups onto quinacridone surface was achieved by the reaction of tert-butyl hydroperoxide with surface acyl chloride groups, which were introduced by the reaction of adipoyl dichloride with amino groups of quinacridone : the amount of peroxyester groups introduced onto the surface was determined to be 0.09 mmol/g by titration. It was found that the radical graft polymerization of vinyl monomers, such as methyl methacrylate (MMA) and N-vinyl-2-pyrrolidone (NVPD) were successfully initiated by surface tert-butyl peroxyester groups introduced onto quinacridone surface to give the corresponding polymer-grafted quinacridone : the percentage of grafting of polyMMA and polyNVPD was determined to be 25.2% and 26.1%, respectively. The grafting efficiency at the initial stage of the polymerization was about 50%, but immediately decreased with progress of the polymerization. This indicates that the formation of ungrafted polymer preferentially proceeds at the middle and last stage of the polymerization. Polymer-grafted quinacridone gave a stable dispersion in good solvent for grafted polymer.
