The rate of strength change by drawing, cross-section change by heat drawing, and X-ray structure changes by draft, drawing and heat treatment were studied on the polyvinylchloride fiber which was prepared by wet-spinning of polyvinylchloride-Tetrahdrofuran solution.
The rate of strength change shows the maximum at the 400% drawing where the heat shrinkage also shows the maximum as reported already. The cross-section changes from symmetrical bean shape to the more flat bean shape passing through a stage of unsymmetrical bean shape like letter “B”, and their skin increases. Also the structure is shown in their core part when heat drawn.
No Change in degree of crystallization by draft is very low. It was observed that crystallization increases increasing draw-ratios under a constant draft, and the intensities of X-ray diffraction increase gradually on 5.38 Å and 3.87 Å. In the constant drawing, the degreeof crystallization is larger in case of higher draft fiber. By heat treatment, the degree of crystallization increases considerably and in the heat treatment under no tension, it is higher than the heat treated fiber under tension. But degree of orientation decreases in the heat treatment under no tension, and is almost the same as in the original fiber under the heat treatment with tention.

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Iodine adsorption experiment was carried out and the following results have been obtained.
In a series of experiments at the different iodinepotassium iodide ratio from 1: 1 to 1: 8, little change has been observed for the adsorption capacity. But in the case of polyvinyl formal, it became smaller as the ratio was decreased.
Except at high concentration, Freundlich'e equation was applicable. The heat of adsorption was obserbed considerably small. Iodine adsorption capacity of the filaments, which were treated at different temperatures, was also measured while the experiments of the water adsorption were carried out with the same samples.
The iodine adsorption values may be considered as a measure for the amorphous parts.
Several other iodine adsorption experiments were also carried out with other fibers; among which 6-Nylon and acetate rayon have shown large adsorption values.
Generally, no definite relation is detected between iodine adsorption and the water adsorption values.

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In order to investigate the relation between the conditions of pulping process and the reactivity of pulp (M-W & S-W by Bartunek), five groups of samples (twenty three kinds of Samples) were prepared by controlling cooking time, bleaching time, hydrolysis time and alkali treatment conditions. M-W and S-W were determined on the samples thus obtained and on the eleven commercial pulps.
From the results some discussion were made on the influences of viscosity of unbleached pulp, degradation of cellulose by bleaching and acid hydrolysis, and α-cellulose contained in pulp on the reactivity of pulp (M-W, S-W) are discussed. The values of M-W and S-W of pulp depend not only on the viscosity and the α-cellulose content in pulp, but also on the morphological and the fine structure of pulp.

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In order to gain more information as to the nature of elastic hysteresis phenomena observed in cyclic loading sliver-like fibre system which had been discussed experimentally in previous paper¹⁾, the present study was undertaken to determine the theoretical relationships between the amounts of tensile resilience φ, dissipated energy loss H and the variations of sliver constants i. e. fibre length _??_, fibre diameter b, density ρ, Young's modulus ε_??_, Poisson's ratio σ, coefficient of friction f, sliver length L and sliver density _??_. By the application of the law of thermodynamics to the double elastic fibre system, it was possible to obtain a general expression of external work W₁ and recovery work W₂ done by the applied load on deformed system in a cycle of extension γ_r.
For the loose sliver having Poisson's ratio ∑₀, the following expressions were derived:
Then, according with the definitions of resilience φ(γ_r)=W₂/W₁, energy loss H(γ_r)=W₁-W₂. it was shown that, in the case of small γ_r.
Where denote the standard measures of hysteresis.
Where Poisson's ratio of sliver, effective Young's modulus of fibre, frictional factor of inter-fibre and specific length of fibre were determined from the given sliver constants respectively. The quantitative behaviour of standard measures of hysteresis φ₀ and η₀ shown in Fig. 7.2 as the function of frictional factor α₀ and specific fibre length λ₀ which varies between zero to unity.
Finally, experiments on the repeated loading for crimped staple sliver and direct roller cutting sliver of viscose rayon fibres have been performed to check the theoretical predictions concerning the precise manner of hysteresis expressed in formulae (2).

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The relationship between tensile recovery and elongation is measured in various loading times, loads during recovery and recovering times with fibers of polyvinyl alcohol and its derivatives, silk, viscose rayon, acetate rayon and perlon L. From the tensile recovery-elongation curves these fibers are classified into three groups, e. g. cross-linkage type, side-chain type and steric hindrance type. Heat-untreated, heat-treated, and tere-phthalized polyvinyl alcohol fibers and perlon L are classified into the first type, formalized, butyralized, and nonalized fibers into the second type, and benzalized fiber, acetate rayon, silk, viscose rayon into the last type. In the cross-linkage type tensile recovery in higher elongation is better than that in lower elongation with the exception in very short loading time. In the steric hindrance type the minimum value in recovery-elongation curve rarely appears, and the effect of load during recovery and loading time for recovery are relatively small. The side-chain type shows the intermediate behavior between the other two types, but the effect of load during recovery is the greatest.

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The article describes the results of experiments dealing with the irregularity of rayon draftcut sliver (two zone draft-cut system).
The theory described in previous reports (Part III and IV), was tested and proved by these expriments the method for experiment used is idential with the case where irregularity of carded sliver was studied.
Chief results obtained are as follows: (a) the draft-cuting of sliver caused unevenness to it quite pertinent to the “stational and normal stochastic process”. (b) in the long and the short term irregularity, each serial correlation and the relation between variance and length of sliver were obtained. (c) tuft length distribution and biased length distribution were required for the fiber which constructed the sliver. From the above results, it is recongnized that irregularity of draft-cut sliver belongs to the type of the “random sliver”.

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Ten kinds of specimens were applied respectively to three types of the fabric abrasion tester (Universal type, Shopper type and UM type).
Each tester gave to the specimens the rank according to their resisting properties against the abrasive action of respective tester. Rank correlations between these results are calculated and discussed.

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The desorption phenomena of dye from cellulosic fibers were observed under various conditions, and the following results were obtained;
(1) The amount of the colour stripped from a fiber dyed with a selected substantive colour varies with the differences of the fixed state of dye particles on a fiber. It will be recognized that the desorption of dye on fiber is not so simple a phenomenon, but a more complex one in which many factors are involved. Of these factors, the microstructures of fiber, the types of colour and the conditions of dyeing seem to be the most important.
(2) A great amount of colour is stripped at a beginning of wet treatments, but the colour stripping decreases rapidly with the increasing of wet treatments. When the test pieces, to which hot water treatment has been repeatedly applied until colour stripping no longer occurs, are treated with a hot alkali solution, a marked colour stripping is observed. Such a result, it is supposed, is obtained from the varying strippability of colours on fiber, in which some parts remain in a state difficult to strip. In view of these phenomena, it is thought that some parts of colours are so fixed mechanically and some physicochemically or chemically. It seems probable that all the dyeparticles fixed mechanically affect mainly the colour stripping with a hot water treatment, and those fixed in a physicochemically adsorbed state greatly influence the colour stripping with a hot alkali treatment.
(3) A fiber which is dyed in weak alkaline dyebath containing Glauber's salt shows colour stripping much more than a fiber dyed in aqueous dyebath. These phenomena are supposed to occur due to the increase of the dyeparticles which are fixed mechanically from coagulation effects of Glauber's salt. Accordingly, it may be fairly asserted that the degree of exhaustion of the dyebath must be kept as slow as possible in the early stages of dyeing so that gradual even distribution of dyeparticles can occur in the microstructures of fibers. Therefore, it can be said that the gradual addition of electrolytes to the dyebath at the final stages of dyeing is the most reasonable dyeing procedure.

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Concerning the desorption of dyes from coloured cellulose crystalline regions, the following facts have been revealed;
(1) At the first stage of wet treatment, a considerable amount of colour is stripped from a coloured cellulose crystalline region dyed with a selected substantive colour. Especially, a coloured crystalline region which has been dyed in weak alkaline dyebath containing Glauber's salt shows a remarkable desorption of colour at the beginning of hot water treatment. It seems most probable that a great deal of colour is fixed mechanically on the surface of crystalline regions owing to the fact that the dye molecules are too large that they can hardly disperse in compact tissue of crystalline regions.
(2) The strippability of colours on crystalline region separated from a cellulose fiber differs considerably from a microstructure of fiber. A coloured crystalline region which has a large rod-like structure, those obtained from cotton fiber, shows the best fastness to various wet treatments. This behaviour is supposed to occur due to the differences of co-ordinate state of dye molecules on crystalline regions.
Generally, all the dye molecules fixed along a long axis of crystalline region seem to exist in the best co-ordinate state, and such portions will probably show the better wet fastness.
(3) The rate of colour desorption on coloured cellulose crystalline region becomes the slower the greater the frequency of wet treatments. Similar behaviour is observed in the case of coloured cellulose fibers as was shown in the previous report. This behaviour is attributed to a nonuniform microstructure of cellulose fibers, composed of crystalline regions of different degree of crystallinity. It would be proper to infer that the fixed state of dye molecules varies with the degree of crystallinity and that those fixed in better cystallized portions reveal the greater wet fastness as it can hardly spread out.
(4) The behaviour of a colour desorption of coloured crystalline region separated from a different cellulose fiber resembles to each other, and the differences in colour strippability of each crystalline region is smaller than that of coloured fiber itself. These differences seem mainly due to the change of dispersed state of dye molecules in microstructure of the fiber.
(5) It is assumed that the polar groups on the crystalline regions were responsible for physicochemical adsorption of each dye molecules, due to the close co-ordination between the activated polar groups in the dye molecules and that of the cellulose crystalline regions. The marked differences of colour strippability of coloured cellulose crystalline regions to wet treatments will probably be attributed to the variations in the fixed state of dye molecules in crystalline regions, owing to the wide difference in the physicochemical crystalline organization.

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