Aqueous dispersing mechanism study of nonionic polymeric dispersant for organic pigments

Polymeric dispersants with varying side chain lengths were prepared via solution polymerization, by using styrene and varying molecular weight of hydroxy polyethylene glycol methacrylate (HO-PEG-MA) as comonomers. The dispersants were used for the effective dispersion of organic pigment, e.g., C.I. Pigment Violet 23. Benzene ring was anchoring moiety while PEG chain was hydrophilic stabilizing moiety, in the dispersant structure design. The chemical structure and surface tension of dispersants were characterized, to correlate their relationship with result pigment preparation performance. It showed that longer side chain length could result in smaller particle size and stronger stabilizing effect. The theory calculations based on Derjaquin-Landau-Verwey-Overbeek indicated that longer side chain length dispersant provided higher steric stabilization energy, which was consistent with experimental results. Graphical abstract