Simultaneous measurement has been performed of the stress relaxation in rubber films and their optical properties, particularly their birefringence, which is the index to their molecular arrange ment, in order to determine what effect the mechanical behavior of rubber films will produce on their crystallization.
Having natural rubber subjected to momentary stretch at various temperatures and at various rates, the different temporal changes of its stress and birefringence have been simultaneously measured with the use of a strain gauge and a photomultiplier, at different moments for an hour from the first 0.1 minute and on subsequent to its stretch. In this instance their X-ray diffraction patterns, respectively under the same situations, have been photographically preserved. The obtained results are as follows:
When natural rubber films are stretched from three to four times their original length at room temperature, their stress and birefringence ordinarily begin to decrease with the lapse of time immediately after the stretch. This tendency holds with its behavior even when the stretch is performed to seven times its original length at higher temperature, say 60°C. The rubber deformation thus made by the stretch to over four times its original length will involve, however, subsequent decrease in stress but increases in birefringence at comparatively lower temperatures. The fall of temperature gives so conspicuously rise to this abnormal phenomenon as to develope it at 20°C when the stretch is made to five times as large length as the original.
What is to account for this phenomenon. In effect it is attributed to the crystallization of the linear molecules in the amorphous region in the parallel direction to that of the stretch. This hypothesis is verified in the examination of its X-ray diffraction patterns.

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Ultraviolet absorption spectra of cellulose films irradiated by light of wavelengths of 2537 A and 1850 A were measured, and it was found that the irradiated sample by 2537 A showed a strong continuous absorption at the wevelength region below 2400 A, while the sample exposed to 1850 A exhibited an intense selective absorption having absorption maximum at 2600 A.
In order to petermine the chromophores thus formed on irradiation by these two spectral lines, the absorption spectra of these two kinds of irradiated samples were compared with those of three kinds of modified celluloses, i. e. hydrocellulose, aldehydic oxcellulose and carboxylic oxycellulose. As the result, it became clear that in the case of 1850 A irradiation, aldehyde groups are the primary product, while in the case of 2537 A irradiation carboxyl groups are mainly formed.

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In this paper, the phenomena of disappearance of the pilling are investigated by means of the microscopic observations.
The phenomena of disapperance of the pilling are very complex, these can be distinguished into two types-degradation in a pill body itself and dropping-away.
The results obtained are as follow:
(1) The phenomena of degradation are carried out in a pill body, which is constructed into a loosely entangled body of the higher elastic modulus fibers such as viscose rayon. Usually the degradation can hardly be observed by naked eyes because of micro-penomena.
(2) The degradation of a pill body may be explained by the fact that the fibers which make pill body are defective in causing slipage and release due to the external actions.
(3) The dropping-away of a pill body may be explained by the facts that the fibers forming pill legs break off due to the fatigue and damage.
(4) Because the scattering states of pill legs on the surface of fabric are remarkably affected to drop-away the pill body, these states are the most important to other shape factors of a pill.

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As part of a study on the factors determining the absorption properties of direct dyes on cellulosic materials, the relation between the dyeing properties and the conjugated system of double bond are considered under the same condition, described in part IX. (K. Nishida; Sen-i Gakkaishi, 16, 575 (1960)). The dyes used are Nippon Dark Green B conc. (C. I. Direct Green 1. C, I. No.30280) (I) and the triazole derivative of Nippon Dark Green B conc. (II). The triazole derivative was prepered from (I) as follow. (I) (1/100mol) in water (300cc) was treated by a good stirring at 90°C. for 1-2hr. with 25% ammonia (10cc) and crystalline copper sulphate (5g) in water (about 20cc). The copper is removed by means of the salt solution acidified with sulphuric acid and the product purified by repeated precipitation with sodium acetate (Ciba, U. S. P. 2788, 3457 (1957)). The absorption band of the dye (I) at about 600 mμ almost disappeares. The amounts of (I) and (II) in equilibrium at the various temperatures were measured. Dyeing was carried in a stoppered hard-glass flasks which was agitated mechanically under the same condition as in previous report (K. Nishida; J. Soc. Dyers Colourists, 76, 551 (1961)). From these results the standard affinity (-Δμ°), the heat of dyeing (-ΔH°) and the standard change in entropy (-ΔS°) of (I) and (II) were determined. The experimental data obtained with (I) and (II) are represented by three quantities, namely -Δμ° (cal/mol)=7200 (I) and 5200 (II), -ΔH° (cal/mol)=6600 (I) and 1700 (II), -ΔS° (cal/deg.mole)=-1.7 (I) and -9.9 (II), respectively. Such difference of dyeing properties may be explained on the following grounds. The dye (II) does not contain any longer conjugated chain than (I), owing to the introduction of insulating groups into the conjugated chain. Therefore, the dye (II) is more bulky.

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