In this paper we studied the molecular mechanism of the cold crystallization upon heating quenched Poly(ethylene terephthalate) (PET). From morphological observations we found spherulites in the samples annealed at lower temperature although it was deduced in early papers that cold crystallization occurs in the form of fringed micellar structure. The cold crystallization kinetics of PET was also examined by the dilatometric method. The dependence of the Avrami exponent on the thermal history indicated that the interpretation of crystallization process in terms of the Avrami treatment is inadequate. A structural similarity was found for samples crystallized by the solvent induced crystallization and by the cold crystallization. The DSC exothermic peak owing to the cold crystallization disappeared in cold drawn PET in which the changes of local chain conformation in glassy state occurred by stress. From these facts we discussed the molecular mechanism of cold crystallization in quenched PET.

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Poly (ethylene terephthalate) copolymers were prepared by substitution up to 40 mol% of diacid comonomers: 2, 5-dichloroterephthalic acid (T_Cl2) and 2, 5-dibromoterephthalic acid (T_Br2). η_sp/C of the copolymers does not depend on the comonomer content. Melting point depression shows that copolymers with T_Cl2 and T_Br2 are non-isomorphous. Glass transition temperature shows a minimum at 30mol% copolymer. The crystallization rate followed by the change of density decreases with increasing comonomer content. Solubility increases by the copolymerization. The resistance to alkali-hydrolysis increases a little for 10mol% copolymer and decreases for more halogen-containing copolymers. Flame-retardancy was estimated by heating the copolymers for 1h at 350°C in air. Weight loss of halogen atoms in the copolymers increases, and residue except halogen atoms in the copolymers decreases with increasing comonomer content. These variations with increasing comonomer content were more pronounced for copolymers with T_Br2 than for those with T_Cl2.

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The multiple membrane method reported by Garvie and Neale to obtain the diffusion coefficient D of penetrant was incorporated in a small diffusion cell to be accommodated in a high pressure cylinder. In the cell, about 20 pieces of thin polymer sheet, each 8mm in diameter, were stacked to build a compact multiple membrane sample, one side of which was exposed, through an open window, to the solution of the penetrant. By using this diffusion cell, Nylon 6 sheet was dyed by p-aminoazo-benzene. Each piece of the component sheet was found to be dyed uniformly to give a distinct circular figure, with monotonically decreasing density from the first membrane. The diffusion profile obtained by a direct measurement of the optical density of each component sheet was exponentially approximated by a function of the type c=c₀ exp (βx^r). Calculation of D was carried out according to Matano as a function of the concentration of the penetrant. Both D at c/c₀=0.5 and D at the concentration of the penetrant which divides the area under the profile into two equal parts were defined. These will be used in our forthcoming researches.

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The affinity of octyl-, decyl-, dodecyl-, tetradecyl-, and hexadecylsulfates for nylon-6 having 5.35×10^-5eq/g amino end-group has been determined at 70, 80 and 90°C by means of the modified Gilbert-Rideal desorption procedure. Orange II (C. I. Acid Orange 7) dye acid was used as the reference dye. The affinity of orange II in acid form was 15.9, 15.4, and 14.8kcal/mol at 70, 80, and 90°C respectively. The affinities of the alkylsulfates were found to be 14.88 to 15.80kcal/mol at 80°C, and increase with an increase in the length of alkyl chain. The adsorption of the alkylsulfates on nylon decreases the heat content and entropy of the system.

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The acid-base equilibrium of an optical probe, 5-dimethylamino-l-naphthalenesulfonyl group, conjugated to silk fiber was investigated by fluorescence measurements in water and in 0.1 M NaCl solution. The apparent pK values of the conjugated probe were smaller than that of the free probe in the aqueous solution and decreased with decreasing pH. The results were interpreted by considering the chemical potential of hydrogen ion and the electrical potential of the fiber phase in Gilbert-Rideal and Peters-Speakman theories. On the other hand, the affinity of hydrogen ion for silk fiber was determined from the adsorption experiments. It was suggested from the comparison of the affinity with the pK value of the conjugated probe that the activity coefficient of hydrogen ion in the fiber phase was reduced to ca. 80% of the coefficient in the aqueous solution.

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Experimental method to obtain the diffusion coefficient D of dye molecule in polymers under high hydrostatic pressures up to 5 kbar has been described. Using the previously reported diffusion cell for the multiple membrane method, D was obtained by Matano's equation for p-aminoazobenzene (pAAB) in nylon 6 (Ny 6) and p-nitroaniline (pNA) in poly (ethylene terephthalate) (PET). The pressure dependence of D was analysed and discussed in terms of the activation volume ΔV^_??_ for diffusion obtained by ΔV^_??_=-RT(∂lnD/∂P)_T where R, T and P are the gas constant, the absolute temperature and the pressure, respectively. At 80°C, ΔV^_??_ was found to be 20cm³/mol for the diffusion of pAAB in Ny 6, while, for the diffusion of pNA in PET at 120°C, ΔV^_??_ was 92 cm³/mol. These results were discussed based on the effective volume of the dye molecules calculated from the unit cell dimensions of the crystalline states and the number of the molecules contained, the textural structure of the polymer matrices, swollen (Ny 6) or unswollen (PET) with water, and the thermal motion of the polymer segment.

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We have previously reported on the treatment of polyester fiber with organic solvent/water. In this paper, high pressure steaming in polyester printing is examined with steam containing a small quantity of organic solvent. Namely, polyester fabric printed with the color paste of C I Disperse Violet 1 was steamed under high pressure with vapors evaporized in a closed chamber from 1%, 5% aqueous benzyl alcohol and butanol solution. Color values of the fabrics steamed with vapors of the mixtures were considerably higher than that obtained by steaming with water alone.
On the other hand, polyester fibers pretreated with vapors of the mixtures were dyed with C I Disperse Violet 1 in water. The partition coefficient and saturation value for the fibers pretreated were higher than those for untreated fiber, especially benzyl alcohol/water pretreatment remarkably increased dye uptake compared to butanol/water pretreatment.
Although there was a considerable difference in dye absorption between the fabrics pretreated with benzyl alcohol/wáter and butanol/water, no difference in the color values after high pressure steaming of the fabric printed with color paste was found between both steaming mediums.
From these results, it seemed that the behavior of color paste during steaming with vapors of the alcohol-water mixtures plays more important role than the structural change of the amorphous region of the fiber for color development in textile printing.

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