Studies were made on the effect of thermal treatment on the conformation and structure of copolypeptides, as models for silk sericin, obtained by the polymerization of N-carboxy anhydrides of the constituent amino acid derivatives initiated by butylamine in acetonitrile and by triethylamine in dioxane. Exothermic peaks of the differential scanning calorimetric curves, appeared at 116°C and 163°C for the copolypeptides as polymerized in acetonitrile and dioxane, respectively, were found to be due to crystallization of the polypeptide chains with the β-form, in such a way that the amino acid side chains transformed into closely packed arrangement by heat-treatment, as was confirmed by sharpening of the X-ray diffraction peaks. The heat-treatment also induced a conformational change of the disordered peptide residues into the β-form, i.e., the formation of intermolecular hydrogen bonds, which played an important role in the heat resistibility.

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Spherulitic polypropylene (PP) films prepared by a melt-quenched process were treated at various temperatures with four organic solvents, chlorobenzene (CB), decalin (DC), dimethylacetamide (DM) and ethylene glycol (EG). These films were then dyed with C. I. Disperse Yellow 7 (Y-7) at 80°C. The equilibrium sorption (M₀) of Y-7 by the films treated with CB, DC and DM increased with increasing crystallinity (C_v), while M₀ of the film treated with EG slightly decreased with increasing C_v Using the fine structural data obtained for the dyed films, the changes in dye sorption were analyzed in terms of the mosaic block structural model. As a result, the M₀ increase with C_v was ascribed to an enhanced sorption in the amorphous side region located parallel to the molecular axis between crystalline cores. The solvent treatments removed atactic fractions and low molecular weight isotactic components from the original films. A conformational change of the PP chains in the side region probably occurred by the solvent treatment. This leads to a possibility that a long rod-like molecule, Y-7, is easily adsorbed on the polymer chain aligned nearly straight in this region.

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The mechanism of the improved dyeability of the grafted poly (ethylene terephthalate) (PET) was investigated, since PET fibers grafted with acrylic acid (AA) and methacrylic acid (MAA) were easily dyed with disperse or cationic dyes. The increase of crystallite sizes or disordering of amorphous region which had found in dyeable PET pre-treated with particular organic solvents, was not observed in the grafted PET fibers, although the PET fibers used in this study were treated with several organic solvents in the grafting process. In contrast, the crystallite sizes of the grafted PET tended to decline accompanied with increasing grafting ratio.
Loss tangent (tan δ) of the grafted PET measured under dry conditions was not different from untreated PET in the temperature region below 100°C. However, tan δ measured in water below 100°C (tan δ_wet) showed a remarkable difference. The tan δ_wet values increased with increasing grafting ratio and shoulder peaks appeared at about 90°C. These shoulder peaks were attributed to the grafted polymers. The results indicated that the grafted hydrophilic polymers facilitated the segmental motion of PET under the dyeing conditions and accelerated the dye-dispersion.

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The method to evaluate the bending rigidities of inhomogeneous cloths was studied.
The results are as follows:
(1) The bending behavior of an inhomogeneous cloth, irrespective of distributions of bending rigidities, was analyzed by the method proposed previously, provided that the cloth was divided into segments (i.e., strips) aligned perpendicular to the longitudinal directions of the cloth and that the segment is consisted of small square elements.
(2) The inherent bending rigidity of inhomogeneous cloths, EI was found to be obtained as its harmonic mean value by the method reported previously, provided that the fixed position of specimen was shifted by one segment after another and that the length of the free portion was adjusted to be kept constant.
(3) If the bending rigidity (EI)_ij of each element is given, it was clarified that EI can be calculated by the following equation: where m indicates the number of elements constituting a segment and n, the number of segments.
Furthermore, the above equation can be expressed by the following complex law: where _??__lk indicates the fraction of a group of elements having an identical bending rigidity (EI)_lk in an arbitrary segment l and K, the number of such element groups in the segment l(K<m). φ_l indicates the fraction of a group of segments having an identical bending rigidity in the longitudinal direction and T, the number of such segment groups (T<n).

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The development of the structure in an aqueous solution of poly (vinyl alcohol) undergoing sol-gel transition was investigated using the light scattering technique. The dynamics of phase separation at early stage of gelation of the aqueous solution was well described within the framework of the linearized spinodal decomposition theory by Cahn. Wavelength of concentration fluctuation with the highest rate of phase separation was about 300nm.

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