The effects of crystalline part on elongation fatigue are studied with model yarns containing dye molecules in crystalline part. The elongation fatigue tests for model yarns are made with the use of the incline tester of Scott type. During the fatiguing, tensile strength of filament increases until certain elongation cycles (fatigue limit), then decreases. The increase of growth (plastic flow) in each yarn against logarithm of cycle may be shown substantially with two straight lines. It is steeper after fatigue limit than before. These fatigue phenomena are not affected by distortion in crystalline lattice and also crystalline part is not changed throughout fatiguing of fibers. Then it may be concluded that fatigue advances in amorphous part.

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In evaluating the effects of chain mobility, stress concentration and growth of hydrogen bond in amorphous part, elongation fatigue tests are performed for rubber and some model tire yarns which contain titanium oxide or foreign polymers in amorphous part. The results obtained are as follows:
(1) Molecular chains are broken down by repeating elongating and fatigue phenomena are observed even in the material such as rubber with good mobility and not causing the permanent set arrangement.
(2) When tire yarn contains foreign materials, such as titanium oxide, polyacrylonitrile and polymethyl acrylate, in amorphous part, cellulose chains in some part suffer stress concentration and fatigue is accelerated.
These results suggest that the homogeneous mobility of cellulose chains is more significant for fatigue life of tire yarns than mobility itself in amorphous part. When the hydrogen bonds arise between oriented chains during fatiguing, force per molecular chain will distribute more evenly, then fatigue resistance will be elevated.

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Elongation fatigue tests are performed for model yarns with different network structure. These samples include the following sets: (1) skin or core rayon tire yarns; (2) yarns cross-linked with formaldehyde, dimethylol ethylene urea or epoxy ethyleneglycol digricidil ether; (3) yarns degraded with acid or γ-ray; (4) yarns made from different stretching process such as stretching after or before regeneration process. The results on these samples suggest as follows:
(1) High degree of chain penetration through crystallite and high degree of uniformity of chain lengths between crystallites give good fatigue resistance to tire cord.
(2) If the cross-linker is long enough to maintain the chain mobility of cellulose, the fatigue resistance is improved.
(3) Denser network such as skin structure gives better fatigue resistance, since it has higher degree of uniformity of chain lengths between crystallits.

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To investigate if there were any difference in acetic acid content between the central zone and the outer zone of the cross section of Alon, the fibrous acetylated rayon, piled cellophane sheets were acetylated in the retention of sheet form with alkali acetate catalyst.
The sheets of cellophane piled could be almost uniformly acetylated in the same manner as was used for production of Alon. There is hardly any difference in acid content between the first (outerest) sheet and the fifth (iunerest) one. One sheet of cellophane is 22μ thick. Hence the thickness of the piled sheets totals 220μ.
On the other hand the raw material of Alon, high tenacity rayon, has a laterally uniform fine structure, not having bilateral structure as crimped rayon, It is 12μ in diameter.
Taking these facts into consideration, it may be concluded that Alon has a microscopically uniform cross section. In other words both the central zone and the outer zone of Alon cross section have the same acetic acid content.
In addition, the accessibilities of various rayons pretreated in different ways are discussed.

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From the studies on the relationship between analytical charactors of wood pulp comparing with cotton linter and qualities of cuprammonium rayon from them, the folowing three points are discussed;
1) α-cellulose content of wood pulp for cuprammonium rayon has more important meaning than that of viscose rayon. It is due to the difference between the processes of cuprammonium and viscose rayon.
2) Hot alkali (10% KOH) solubility suggests the easily destroyable amount of cellulose of wood pulp in cuprammonium solution. 10% KOH solubility is therefore very important, charcterizing quality of wood pulp for cuprammonium rayon. It is matter of a great interest, whether such wood pulp may be produced or not, which shows the same behavior in hot alkali solution as in cotton linter.
3) Turbidities of dissolved cellulose by acetylation of varous wood pulp were in good accordance with suitabilities to wood pulp for cuprammonium rayon.

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The absorption isotherms of four disperse dyes for polypropylene fibers were determined at various temperatures. The affinity, heat of dyeing and entropy of dyeing were calculated from the thermodynamical treatment. The heasts of all four dyes investigated were all negative, so the binding process was exothermic. The affinity of the dye for polypropylene was found to increase with the increase in the hydrophobic character of the dye. The increase in the hydrophobic character of the dye, however, causes the decrease in the heat and entropy of dyeing. This result shows that the higher affinity of the hydrophobic dye comes from the decrease in the entropy of dyeing. From a consideration of the thermodynamical data, it is assumed that the breakdown of so called “iceberg” water structure in the vicinity of the hydrophobic dye takes place in the course of the binding process. The interaction between polypropylene fibre and disperse dye is explained by using the following concept that the binding process involves two main effects: (1) an exothermic interaction (may be dispersion force) (2) an entropic interaction (the formation of a so called. “hydrophobic bond”)

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The cylindrical cellophane-film roll was dyed with some direct dyes, under certain conditions (dye 0.02g, NaCl 0.4g, Noigen HC 0, 0.1, 0.2, 0.4, 0.8, 1.6g per 400cc of bath, temperature 90°C, dyeing period 25hr).
The cellophane-film roll was obtained by winding up the cellophane-film (6cm wide, 55cm long and 0.0042cm thick in wet state) around the glass tube of 0.9cm in diameter.
After dyeing, the dye concentration of each layer was determined colorimetrically. Assuming that the system is equivalent to the dyeing of a semi-infinite media (substrate) with constant dyebath concentration, the diffusion coefficient D, surface concentration C_o, (proportional to the ammount of equilibrium adsorption) and “dyeing index” C_o√D were obtained from the dyeing conditions above mentioned.
1) As the amount of Noigen HC increases, both C_o and D for each dye decrease.
2) The higher the value of C_o of dyes is, the more remarkable is the effect on C_o.
3) As to the dyes with high value of C_o and very low value of D, the effect on C_o√D is slight.

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An attempt was made as to compare original dyeability between wet-spun formalized vinylon and cellulosic fibers such as viscose rayon and cotton. The dye on fiber and the color-depth and the color-shade of wet-spun formalized vinylon, that fineness and tenacity approximated to those of the viscose rayon and cotton with each other, were measured, and the following results were obtained. The dye on wet-spun formalized vinylon in the formalizing bath containing sodium sulfate, in the standard dyeing condition were equal to other fibers, but the color-depth and the color-shade on the dyeings were inferior to the properties of other fibers. The color-depth on dry-spun formalized vinylon is better than the dyeability of viscose rayon, and it almost approaches the property cotton has.

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