Influence of metal and nonmetal doping on wetting and dispersing characteristics of TiO2 pigment for coating applications

Dispersing of pigment particles in paint medium is the hardest stage in paint and coating production. Pigment agglomerates must be wetted, separated, and dispersed in paint matrix with a suitable distance from each other. In the present work, we have studied the effect of doping of TiO2 pigment with metallic and nonmetallic elements on its wetting and dispersing properties. For this reason, TiO2 pigment was doped with Cu as a metallic and N as a nonmetallic element. Doped pigments were characterized by XRD, SEM, and FTIR and then wetting properties of the obtained pigments were tested by contact angle measurement with water. Also dispersing properties of pigments were studied by grinding time (dispersing time) in the ball mill apparatus. The results showed that doping of TiO2 pigment with metallic element Cu reduced the contact angle whereas doping with non-metal element N caused to increase in the contact angle. Also, a complete test series of coatings prepared with these two doped pigments in comparison to unmodified pigments showed that the final properties of the paint film weren't affected by utilizing doped pigments.