Hyo-Kwang Bae

Dye distribution in supercritical dyeing with carbon dioxide

Abstract The measurement of equilibrium dye uptake in PET fiber is carried out using a flow-type cylindrical vessel. Using the expanded liquid model in which both phases are supposed to be liquid mixtures, the equilibrium uptake of C.I. disperse red 60 may be calculated from each binary interaction parameter of carbon dioxide–dye, carbon dioxide–PET and dye–PET binary systems. The calculated uptake is compared with the observed one with the same order of magnitude, even though the former is overestimated. The binary interaction parameter of dye–PET system that is obtained from the equilibrium dye uptake in PET is smaller by about 1.5 than that obtained by the binary system. Nevertheless, it is found that the predicted uptake of dye with using the interaction parameter regressed from the ternary data is in excellent agreement with the experimental one. The distribution of C. I. disperse red 60 into supercritical fluid and PET phase at equilibrium can be predicted and compared with the experimental one. The estimated distribution coefficient increases with the pressure increase, because the sorption of dye in PET fiber increases slowly with the pressure than the dye solubility in carbon dioxide does. This tendency is weakened with increase of temperature.

Dyeing of pet textile fibers and films in supercritical carbon dioxide

Polyethylene terephthalate (PET) textile fibers were dyed with a disperse dye in the presence of supercritical carbon dioxide at three temperatures of 333.2, 363.2 and 393.2 K and at pressures between 15 and 25MPa. The PET film was also dyed at 393.2 K. It was found that the dye uptake in the fiber increased 2–5 times when a small amount of acetone was added as a cosolvent. The equilibrium dye uptake increased with increasing pressure at all temperatures. At 393.2 K the pressure effect appeared to be much larger. It was explained with the shift of the glass transition temperature of the polymers at high pressures. These results may be useful in designing and developing the pollution-free supercritical dyeing technique, a potential alternative to the conventional dyeing of polyesters that produces a lot of wastewater.

DYE SOLUBILITY IN SUPERCRITICAL CARBON DIOXIDE. EFFECT OF HYDROGEN BONDING WITH COSOLVENTS

The use of supercritical carbon dioxide is emerging as a potential method for achieving pollution-free dyeing. An important factor in supercritical fluid dyeing is the solubility of the dye in supercritical carbon dioxide. Our measurements show that the solubility of C. I. Disperse Red-60 dye in supercritical carbon dioxide is significantly enhanced upon addition of polar csolvents : ethanol and acetone. The solubility enhancement is attributed to the formation of hydrogen bonds between cosolvent and dye molecules. Observed solubility behavior is correlated using dilute-solution theory with lattice-fluid-hydrogen-bonding model. Needed physical and hydrogen-bonding molecular parameters are estimated using the experimental data.

A method for the prediction of critical temperature and pressure of pure fluids

Abstract Bae H.-K., Lee S.-Y. and Teja A.S., 1991. A method for the prediction of critical temperature and pressure of pure fluids. Fluid Phase Equilibria , 66: 225-232. The critical temperatures and pressures of 213 organic compounds have been estimated using the Peng-Robinson equation of state, based on a knowledge of the van der Waals volume, normal boiling point and acentric factor of the substances. Comparisons with the group contribution methods of Lydersen and Ambrose are shown and the average absolute deviations between the experimental and calculated properties according to the present work, the Lydersen method and the Ambrose method are 0.52, 0.91 and 0.70%, respectively, for critical temperature, and 4.87, 5.82 and 3.84%, respectively, for critical pressure.

Excess molar volume of acetone, water and ethylene glycol mixture

The excess molar volumes for binary acetone+ethylene glycol and acetone+water mixtures whose components represent strong polarity and association were measured at temperatures 283.15 K and 293.15 K, by using a vibrating tube densitometer. Those of ternary mixtures composed of each component were also obtained at the same temperatures and compared with the calculated values from regression by utilizing the Redlich-Kister polynomial equation.