The mechanical properties of lint were daily measured in relation to the development of the micro-structure of primary and secondary cell wall during the growing process of cotton fiber. The cotton variety used for this research was “Rikuchimen Kan-no No.I”, a sort of upland cotton.
The strength increases and the elongation decreases linearly with age of fiber, from the beginning of wall thickening until when wall thickening is just completed, and thereafter both strength and elongation show constant value until when boll opening just finishes. (strength 5.9g/lint, elongation 9.8%, after boll opening.) On the other hand, the strength per unit section area of lint begins its increase early in the growing process of elongation and attains a constant value (about 25kg/mm²) already at the day when wall thickening just begins.
The contribution of the primary cell wall to mechanical strength per unit section area is less than that of the secondary cell wall. The increase of the mechanical strength in the secondary cell wall is directly proportional to the increase of net area.

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Viscose rayon is pretreated to imbibe various liquids and then acetylated in fibrous form with the following acetylation bath: acetic anhydride, diluent and sulfuric acid (in form of sullo acetic acid). The rate of acetylation differs widely by the conditions of acetylation. It depends upon the kind of imbibition and diluent liquid and catalyst. The first step of liquid phase fibrous aeetylation consists in the displacement of the imbibition liquid with the acetylating bath. It seems that the easiness of the displacement, which depends upon the above mentioned factors, is dominating in the rate of acetylation. Cohesive energy, densities of various liquids are calculated and the easiness of the displacement discussed.

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Viscose rayon which has been pretreated to imbibe various liquids is subjected to fibrous acetylation using perchloric acid as a catalyst. The catalytic action of perchloric acid is much greater than that of sulfoacetic acid. In both cases the influence of the imbibition and diluent liquid on the rate of the acetylation is similar. When methanol or ethanol is used as imbibition liquid the acelylation takes place smoothly with the perchloric acid catalyst. This may be attributed to the acceleration of displacement of imbibition liquid by the chemical reaction between alchol and acetic anhydride.

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The semichemical pulp made from red pine by neutral ammonium sulfite process, a number of phenomena observed in cooking and qualities of the pulps obtained are compared with those of Na base process. The results are as follows:
1. At the same pH condition the cooking velocity by NH₃ base is somewhat larger than that by Na base. The cooking by both NH₃ and Na bases showing the same amount of SO₂ consumed give the same amount of pulps, yielded. (Vide; Fig. 8, 9)
2. As compared to the pulp obtained by Na base that by NH₃ base is darker in colour, the same in Roe number and breaking length, and somewhat lower in pentosan content and specific bursting strength. The last quality, is somewhat improved by cooking in higher pH using some pH control reagent. (Vide; Fig. 10, 11, 12, 13)
3. In bleaching the pulp cooked by NH₃ base it shows the same degree of brightness as that by Na base with the same pulp yield. (Vide; Fig. 14)
4. To keep the pH of liqur always more than 7 throughout the cooking, the pH of the liquor at the start must be about 9. For this purpose the needed amount of NH₃ or NaOH is about 0.4g/ 100cc liquor, which is equivalent to 28% of NH₃ needed to prepare the NH₃ base liquor of pH 7, containing 2.5% SO₂.

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This paper is devoted to evaluate the general relationships in connection with mechanical properties of sliver-like fibre system with those of constituent fibers and to investigate the application of these relations to the particular case of extension of regular staple rayon slivers.
Theoretical formula of load P-extension γ curves of sliverlike system is expressed by: Here Young's modulus E₀, Poisson's ratio Σ₀ of sliver are dependent upon (1) sliver structures; gauge length L₀, cross section A₀, density _??_₀, (2) fibre properties; Young's modulus ε_f, Poisson's ratio σ, coefficient of friction f, and (3) fibre dimensions; mean length _??_₀, diameter b₀, density ρ₀.
Then we have:
These expressions suggest that P(γ) curve may be inverse sigmoidal, concave, sigmoidal or convex in accordance with the change of sign of constants, b and c.
The experimental results of constant-rate of loading tensile tests for the regular staple rayon sliver indicate that their load-extension curves are sigmoid, and that their Young's modulus, Poisson's ratio, breaking strength and breaking elongation are related to the sliver structures and single fibre properties, and can be predicted from them fully.
The observations also show that stick-slip movement of fibre in extension of sliver is a function of sliver length and rate of loading.

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In this papers a tensile strength tester of portable type with autographycal recording apparatus for stress-strain diagram of the textile materials, single fibers, yarns and clothes, is described.
This tester is constructed with following five units.
1) Clamps holding the test piece
2) Loading mechanism
3) Recording mechanism
4) Pressure regulator equipment
5) Air compressor
On this tester the load is measured by the deflexion of a leaf spring which is connected to the test piece, and the deflexion is detected by the principle of the air micrometer.
As the deflexion of the leaf spring is very small, the elongation of the test piece is equal to the distance of the pull at one end of it. The stress-strain diagram of the test piece is recorded on a piece of paper by the air micrometer mechanism and the pulling mechanism.
If it is necessary to be changed the sensitivility of measuring lord, it can be adjusted by changing the leaf spring or by changing the distance between two supporting points of the spring.

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Investigations are made concerning manners in which residual shrinkage of various nylon textiles are varied by heat setting.
It is found that the dissipation of internal stress begins at lower temperature in the textiles with larger initial internal stress, than in those with smaller initial internal stress.
From the experimental results, it is suggested that the internal stress can not be readily treated quantitatively, but it should be expressed statistically as a superposition of various stresses with different energy levels.

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It is a well-known fact that vinylon is swelled or solved by piridine, nitro-benzen, phenol, cresol and so on.
Utelizing this nature of vinylon, phenol and others are used for increasing the penetration of dyes.
The degree of swelling and the decrease of elongation and strength in vinylon is investigated by using phenol as a swelling agent, (vinylon blended fabric of equal parts of vinylon and viscose spun rayon, and viscose spun rayon fabric are used and then vinylon is applied to a conventional urea-formaldehyde resin procession to observe the effect, which is found satisfactory, in accordance with a presumption that the small chinks in the skin-stratum of vinylon will be enlarged by this swelling agent and that the resin solution penetrating through the chinks will cause condensation in the interior of the sponge-stratum.
The results may by summarized as follows:
(a) In the case swelling treated vinylon fabric, the decrease of its strength occurs, hut because of resin finishing the effect is more satisfactory than unswelling vinylon.
(b) Increase of the internal condensation of resin is greater than in unswollen vinylon.
(c) Vinylon and viscose spun rayon fabrics 50% blended is found to be of more practical value than 100% vinylon fabrics.
(d) The case of initial condensed resin finishing shows better results than the uncondensed resin.

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The purified sheets of the cellophane are dyed with some selected dyes. By dyeing the maximum wave length of these spectra of dyes is shifted to red side, as compared to these of aqueous solution. The dyes are classified into three groups, according to the deformation of the absorption curves of the dyed sheets by the dyeing and dry heating. (a) By the dyeing the new absorption, which clased after heating, is developed to red side of the maximum wave length, and consequently the color change is observed. (b) The same new absorption is shown, but the deformatian of the curve can not be observed by heating. (c) After dyeing no such deformation of curve is shown, except the shift of the maximum wave length and the change of absorption coefficient.
In the case of the dyes of group (a), Azoorseillin and Benzoazurine G, which are substituted by OH groups at the ortho positions of both azolinkages, the color change is greatly improved by treatment with CuSO₄ solution. The above new absorption reaches the peak of the vissible region by this treatment without deformation by heating. The new absorption of the dye of group (b), Bril. Purpurine lOB which has no OH group, is not decreased by heating or not affected by Cu treatment. In the case of the group (c), Congo Red, Benzopurpurine 4B, Congo Corinth G, B and Azo Violet, containing some dyes that are substituted by a OH group at the ortho position of azo linkage, too new absorption under the dyeing, heating or Cu treatment are observed.

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