Effect of molecular composition of comb-like polycarboxylate dispersants on hydrophobic dye dispersion properties

Abstract

Six different polymers were synthesized to understand the effect of the chemical structure of comb-like polycarboxylates on hydrophobic dye dispersion. They varied in terms of molecular weight and side-chain density. Polymers characterization using Raman spectroscopy confirmed accomplished copolymerization using acrylic acid and tresylated polyethylene glycol. Further characterization indicated half of the polymers are in the range of 20 ± 4 kDa while others are in the range of 10 ± 1 kDa. The application of polymers as a dispersant was evaluated in dye dispersion and ink formulation. It has been found that lower molecular weight polymers resulted in dispersion instability. Moreover, a higher side-chain density of polycarboxylates led to the formation of more stabilized dye dispersions. Effective dispersant adsorption onto the dye particle surface was shown by zeta potential measurement. Also, it was indicated disperse dye solubility increased using the dispersants. The dispersants were successfully applied to ink formulation and the best dispersion stability, lowest dye particle size, lowest viscosity, and lowest surface tension were achieved using the polycarboxylate with the highest molecular weight and the highest side-chain density within the experimental range. Finally, inks were used for sublimation printing on polyester fabrics, and the color characteristics of the printed fabrics were assessed. This study introduces high-performance and cost-effective dispersants for the ink manufacturing, and textile industries.