Stability of Dye Dispersions in the Presence of Some Eco-Friendly Dispersing Agents

摘要

The stability of dye dispersions in the presence of ethoxylated sorbitan lauryl and oleyl esters were reported and compared with dye dispersions containing a conventional dispersing agent, i.e. naphthalene sulfonic acid methylene-bis sodium salt (NSAB). The optimum operating conditions obtained using a central composite design and stability of dye dispersions were evaluated by a turbidimetry method. Results showed that the dose of surfactants and the temperature of operation were important factors in preparing stable dye dispersions. Also, the best conditions for preparing dye dispersions were as follows: dose of surfactant 0.05 g, temperature 25 °C and time 5 min. In addition to, findings indicated that both of the used surfactants had better performance in dispersing the dyes in water. However, ethoxylated sorbitan oleate had better efficiency relative to other used dispersing agents. The performance of both sorbitan esters were compared with NSAB. The results indicated that they can create stable dye dispersions in aqueous media and have approximately the same effectiveness with NSAB. In this series, although oleate ester had a better performance than the laurate, the difference in performance of using dispersing agents was not significant. This finding was confirmed by the results of the particle size analysis of dye dispersions.