Preparation of polyether amine-bridged lignosulfonate for utilization as a nano dye dispersant

The long-term stability of nano disperse dye slurry is a problem in industry. In this work, high molecular-weight polyether amine-bridged lignosulfonates (PEABLs) were prepared to improve the adsorption strength of dispersants on dye surfaces, and thus the stability of nano disperse dyes. Specifically, the molecular simulation software was firstly used to analyze the adsorption of PEABL on dye surfaces. Then, PEABLs with different molecular weights were synthesized and characterized by adjusting the addition of polyether amine. Next, nano disperse dyes were prepared using PEABLs and the optimum grinding conditions were explored and obtained. Finally, PEABL3 was determined to the optimum dispersant, having a smallest particle size (168 nm) and highest stability, comparable to the commercial Reax 85A dispersant and basically satisfying the demand of nano disperse dyes required in digital transfer printing technology. Quartz crystal microbalance (QCM), atomic force microscopy (AFM) and zeta potential results showed as the molecular weight of PEABL increased, the adsorption amount, adsorbed layer rigidity, adsorption force and absolute zeta potential value all firstly increased due to the enhanced hydrophobic interaction, and then decreased due to the formation of complicated three-dimensional network structures caused by the crosslink of lignosulfonate molecules. A maximum was observed for PEABL3.