Preparation and Utilization of a Comb‐Like Polycarboxylate Dispersant for Organic Pigment

As a novel form of carboxylate comb‐like copolymers, SAM‐(m)PEG was prepared by polymerizing styrene (S), acrylic (A), and maleic anhydride (M) to obtain a random copolymer labeled SAM. SAM was then esterified using either polyethylene glycol (PEG) or methyl PEG (mPEG), a waterborne polymer dispersant for dispersing and stabilizing C.I. Pigment Yellow 180 (PY 180). The structures of SAM‐(m)PEG and the ground suspension of PY 180 were characterized by Fourier transform infrared (FT‐IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), a nanoparticle size analysis, and viscometry. The effects of different branch chains, synthetic formulas, and grinding conditions on the dispersibility of SAM‐(m)PEG were evaluated. In addition, the optical properties of the pigments were investigated after ultrafine grinding. The adsorption mechanism between the SAM‐(m)PEG dispersants and PY 180 particles is also discussed. SAM‐PEG600 2 outperformed the other SAM‐(m)PEG dispersants owing to its excellent dispersion and stability. When used as the dispersant, the average particle size (Z‐average) of PY 180 after grinding was 264.6 nm, and the particle size distribution became narrow (PDI=0.089). Moreover, SAM‐PEG600 2 effectively maintained the color performance of the pigment, and the product was successfully applied to the pigment coating. Therefore, SAM‐PEG600 2 is an effective waterborne polymer dispersant for organic pigments.