Isotherms were measured for the distribution of three pure non-ionic dyes and their binary mixtures between polyethylene terephthalate and water in the presence and absence of benzoic acid. In each case, the equilibrium concentration of dye in the fibre was directly proportional to the concentration in the water. For a binary mixture of greatly dissimilar dyes, each behaved completely independently of the other, while for a mixture of two closely related dyes some interference was noted. The solubilities of the dyes in both the fibre and the water increased with a temperature increase and the isotherm was displaced toward the water. The presence of benzoic acid displaced all isotherms toward the water.It is concluded that sorption of non-ionic dyes by polyethylene terephthalate takes place by a solution mechanism.

Time-resolved small-angle X-ray scattering is used to investigate the time dependence of structure formation at the ordering transition in bulk diblock copolymers. After a quench from the disordered into the ordered state two relaxation processes are found on well-separated time scales. The slow process displays an unusual temperature dependence and is discussed as a nucleation phenomenon.

DACRON polyester fiber was introduced to the textile market by due 1'ont in 1950. Since that time, many millions of pounds of this new fiber have leen dyed by two principal methods: ( 1 ) It has been dyed at temperatures above 100° C.-in pressure vessels.(2) It has been dyed at temperatures of 100° C. or lower by adding organic compounds called carriers to the dye bath to increase the dyeing rate.In a search for carriers, it was found empirically that many organic compounds increased the rate of dyeing [3J. It is agreed by some that this increase in the rate of dyeing resulted from an increase in the rate of dye diffusion through the filier. There is disagreement, however, on the mechanism by which this is accomplished. Vickerstaff 151 summarized some of the current ideas a, fol1óws: ( 1 ) Small polar compounds, such as phenol, diffuse readily into I)acron polyester fiher and are absorbed by hydrogen bonding, Being hydrophilic. these compounds then attract water molecules into the nber. leading to swelling and greater ease of diffusion. (2) Hydrophobic dyeing assistants, such as benzene, biphenyt. and chlorohenzene, could act in one of two ways. The original theory considered the carrier to he a corn pound that literally carriers the dye into the fiber by complex formation. A later idea suggested that the carriers decrease polyn1<'r interehain forces, reducing internal viscosity, and thus permitting greater dye diffusion rates.Quite a different pusition Is taken hy ('ho(luette 111. He suggested that chlorubenzene promoted -faster dyeing of Dacron lH~lyester nber by producing a layer of concentrated dye solution around the IlIK-r thereby promoting absorption and penetration.Zimmerman I H -ilso does not helieve tha~t ~BB'ellillgis important in the mechanism of carrier acticrn. I te proposed that the dye is soluble in the carrier in the monomolectilar state. The rate of dyeing is therefore increased because vingle molecules diffuse intll the fiber more rapidly than dispersed aggregates of dye molecules.V'aters (7) discussed the efficiency of carriers.He theorized that the distribution of carriers hetween the fiber and the aqueous dye bath is important in carrier activity. Fern and Hadfield ~ 121 surest that water-soluhle carriers plasticize the fi1.(>r. Water inso1uhle carriers 1>lasticize the fiher, and in addition surround the fiber with a sulvent layer in which dye is highly soluhle. I)yeing rate is then further arrelerated by the increased concentration gradient All of the work cm the carrier dyeing of Dacron reported in the literature has 1.een carried out in aqueous dye baths Neither the dyes nor the carriers are usually completely so!ub!e in water. Thus. it is difficu1t to specify their concentrations, and to compare then) on an equa1 hasis.The present investigation is concerned with carrierdyeing phenomena in an essentiany non-aqueous systetn (isooctane saturated with watert. where homogeneity of the dye hath phase 1)eriiiits specincation of carrier and dye concentrationThe results obtained can best he inter...

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