Copolyester Studies. IV. Dyeing Behavior of Drawn and Undrawn Fibers Derived from Tetramethylene Terephthalate–tetramethylene Sebacate Copolymers

Drawn and undrawn fibers of tetramethylene terephthalate–tetramethylene sebacate copolymers, containing up to 20 mol % of the latter, have been dyed in an infinite dyebath with a disperse dye. The dyeing process has been interpreted in terms of the equilibrium dye absorption, the half-time of dyeing, and the diffusion coefficient. Increasing sebacate content has been found to have a marked effect on the rate and level of dye uptake. Deviations from Fickian behavior have been observed for the drawn fiber and related to presence of voids.