Rheological behavior and storage stability study of liquid disperse dyes stabilized by polycarboxylate hyperdispersants

Liquid disperse dyes (LDDs) have broad prospects of application due to their advantages in environmental sustainability, public health, and energy conservation. In this work, three different polycarboxylate hyperdispersants containing solvating groups and different functional groups were successfully synthesized by free radical polymerization and used in the preparation of ECT black LDDs. After 90 days of storage, the LDDs stabilized with AHT and AST retained good stability, with respective dye particle sizes of 401 nm and 425 nm. In contrast, the particle size of LDDs stabilized with AAT was 679 nm. The absolute Zeta potential value of LDDs dispersed with AHT and AST was more than 30 mv. The rheological properties of LDDs were further characterized to study the stabilization mechanism of the LDDs. The results showed that LDDs prepared by three dispersants exhibited shear-thinning fluid behavior. LDDs dispersed with AHT and AST had higher storage modulus, loss modulus, and yield stress than that of LDDs prepared with AAT. All the LDDs showed a shear sensitivity behavior and the percentage viscosity recovery for LDDs dispersed with AHT, AAT, and AST was 94.4 %, 77.8 %, and 86.9 %, respectively. In addition, compared with commercial powder dispersion dyes, the chemical oxygen demand (COD) of residual liquid after dyeing with LDDs was reduced by more than 60 % due to less use of dispersants. Collectively, these results indicate that this study can facilitate the optimization of LDDs formulations and holds significant potential for the production of high-quality LDDs products.