Silanized TiO2 nanoparticles and their application in toner as charge control agents: Preparation and characterization

Surface modification of TiO 2 nanoparticles with 3-methacrylic acyloxy propyl trimethoxysilane (KH570) was carried out in the liquid phase. As additives, the modified TiO 2 nanoparticles were employed as charge control agents (CCAs) in the toner. The hydroxyl groups on the surface of TiO 2 nanoparticles can interact with methoxy groups of KH570 and an organic coating layer formed. The Ti O Si bond was testified by Fourier transform infrared spectra (FTIR). Through transmission electron micrograph (TEM) observation, it was found that the organic coating layer was about ∼3.1   nm and the dispersibility of the modified TiO 2 nanoparticles were obviously improved. Static water contact angle was used to investigate the wettability of the modified TiO 2 surfaces. The results indicated that the hydrophobicity of the modified TiO 2 nanoparticle surfaces could be effectively improved as the amount of the coated KH570 increased. The specific surface area (SSA) of the modified TiO 2 was determined by Brunauer–Emmet–Teller (BET) method. Surface morphology of the modified toner and the toner charge were investigated by scanning electron microscopy (SEM) and electrometer, respectively. The modified toner showed smoother surface and the toner charge was adjusted by the modified TiO 2 nanoparticles. The charge-to-mass ratio (Q/M) values shifted to the negative direction, for example −13.25   μC/g, with an increasing coated KH570, probably due to the OH groups existing on the surface of TiO 2 .