Structure and Properties of Sodium Lignosulfonate with Different Molecular Weight Used as Dye Dispersant

Three purified sodium lignosulfonates (SLs) with different molecular weights were prepared by ultrafiltration. The structural characteristics of SL and their effects on the properties of dye were investigated. When the molecular weight is increased, the chroma, purity, and the content of guaiacyl of SL increases, whereas the phenolic hydroxyl, carboxyl, and sulfonic groups in SL decrease, the dispersibility, heat stability properties, and dyeing rate of SL on dye improve, and the fiber staining of SL weakens at high concentration. The fraction of SL with the cutoff molecular weight above 2.5 kDa has the weakest reduction effect on dyestuffs.