Dyeing Properties of Segmented Polyurethane Containing Polyethylene Glycol as Hydrophilic Group

The segmented polyurethane films having different composition ratios of PTMG and PEG in the soft segments were prepared. The films with different water absorbability were dyed with CI Acid Red 114 and CI Direct Red 28, respectively. Dye uptake of CI Acid Red 114 in the films increased by adding formic acid into dye bath. On the other hand, dye uptake of CI Direct Red 28 in the films increased by the addition of sodium chloride into dye bath. In any combination of the dyes and the films, the resulting sorption isotherms might indicate the Freundlich-type dye mechanics. Dyeing properties of the segmented polyurethane films containing polyethylene glycol with acid dye and direct dye were as follows ; (1) The dyeing was performed mainly in soft segments of the segmented polyurethane. (2) The segmented polyurethane films were dyed into the hydrophobic parts composed of urethane bonds in the neighborhood of hydrophilic PEG component. (3) The hydrophobic interaction between the dye and the segmented polyurethane became the big power as to the dyeing of the segmented polyurethane having the hydrophilic soft segment consisting of PEG. The effect of the dyeing by van der Waals forces on the segmented polyurethane seemed to be big as to the dyeing of the polyurethane.