Kuanjun Fang

Properties of the Nanoscale Hydrophilic Cationic Pigment Based on Quaternary Surfactant

Dispersions of four nanoscale hydrophilic cationic pigments were prepared by micro jet milling process, in which the dodecyl trimethyl ammonium chloride (DTAC), tetradecyl trimethyl ammonium chloride (TDAC), hexadecyl trimethyl ammonium chloride (CTAC), and octadecyl trimethyl ammonium chloride (STAC) were used as the dispersers respectively. Zeta potential, particle size, viscosity and dispersion stability were tested. The effect of the hydrophobic chain of cationic quaternary surfactant on pigment dispersions properties was discussed. The results showed that good dispersion effects were obtained when the hydrophobic chain were 14 or 16.

Dyeing of Lyocell Fabrics with Pigment Dispersion Systems

Lyocell fabrics modified by cationic reagent were dyed with conventional and nanoscale pigment dispersions respectively. The color yield and fastness properties were measured. It is found that the color yield and fastness properties of the dyed lyocell fabrics are influenced by the cationic reagent concentration, the cationization pH, time, and temperature. It is also found that the nanoscale pigment system can give the lyocell fabric a higher K/S value but with lower rub and wash fastness. The wet abrasion time, which is used to indicate the fibrillation tendency of lyocell fabrics, was also measured after the cationization and pigment dyeing. The results show that the multifunctional cationic reagent and the pigment on the lyocell surface could increase the wet abrasion time but by different mechanisms.

The Effect of pH Value on Properties of Waterborne Nanoscale Pigment and the Estimation of the Solvated Layer Thickness

Waterborne nanoscale copper phthalocyanine blue (P.B.15:3) dispersion was prepared by phase separation method. The effects of pH value on its properties were investigated and the thickness of solvated layer enclosing the pigment was estimated by the method of dynamic light scattering. The results show that the particle size first increased and then decreased with increasing pH value in the range of 1.0 to 12.0, and would be changed sharply when pH value was higher than 12.0 or lower than 1.0; the changes of the absolute Zeta potentials and the apparent viscosity were similar to that of particle size in the range of 1.0–12.0; the stability of the pigment dispersion was quite high when its pH value was in the range of 7.7–10.0. The stability, the Zeta potentials, the apparent viscosity, and the thickness of solvated layer (about 10 nm) reached their maximum at the pH value of 9.0.