Mechanical properties of polyvinylchloride fiber, which was made by spinning of 12% polyvinylchloride-tetrahydrofuran solution into water and drawn by constant velocity to 500% in 70±2.5°C hot water bath, were studied and the following results were obtained.
Denier decreases by drawing, and tensile strength (g) gives two constant values of 2.3 and 3.3g in 100-250 and 300-500% drawing respectively, but knot strength decreases by drawing over 300%. Tensile strength (g/D) increases and elongation decreases by drawing. Wet-dry ratios of tensile strength are 100% by the drawing over 350%. Wet-dry ratios of elongation, and knot-ordinal ratios of tensile strength and elongation decrease by drawing.

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Axial heat shrinkage of polyvinylchloride fiber drawn to various extent were measured at 30-130°C and the following results were obtained.
As the temperature is increased heat shrinkage will increase and the rate of shrinkage becomes higher near the second order transition temperature of polyvinylchloride.
In accordance with the increase of the extent of drawing, heat shrinkage increases, but in the drawing over 400% it decreases. There are interesting relations between the ratio of drawing and the under area of the curve of shrinkage.

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To know the behavior of low polymers towards the ripening process of secondary cellulose acetate, and to clarify the effects of degree of polymerization, sorts of hydroxyl groups and end-groups on saponification rate, the influence of temperature and composition in acetic acid-water-sulfuric acid system on reaction rate were investigated.
It seemed that the reaction is first order on ester concentration and the reversible monomolecular reaction which is independent of water, is more probable than the reversible bimolecular reaction.
The reaction my be considered as the intermedeate state between the mono and bimolecular reaction or it may be due to the abnormal activity of water in acetic acid. Sulfuric acid is regarded as catalyst which only accerelates the reaction, but does not change the equilibrium.
The high reaction rate in initial stage may be due to its end-groups. The activation energy derived from the temperature dependence of the reaction rate is lower than that of xylose. It is elucidated from the existence of the primary hydroxyl group.

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The effects of temperature and composition in acetic acid-water-sulfuric acid system on the reaction rate were studied. The reaction is inclined more to the reversible monomolecular reaction than to the bimolecular reaction, because of little dependence on water concentration. But its strict fitting is not obtained. It may be also elucidated from the abnormal activity of water in acetic acid Sulfuric acid seems to exhibit only catalytic action. The high initial reaction rate may be ascribed to the end-groups. The change of its rate with temperature reveals that the activation energy is lower than that of xylose, as of cellobiose and cellulose. It may be due to the presence of the primary hydroxyl group.

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The effects of degree of polymerization, water concentration and temperature on the saponification rate of fractionated cellulose triacetate in the system of acetic acid-water-sulfuric acid were investigated. The reaction follows nearly the reversible bimolecular reaction on water and ester. In the initial stage, a high reaction rate was observed, and it is explained by the effect of the end-groups. Increased degree of polymerization from 30 to 60 affects no significant difference in the reaction rate, but its rate is slower than that of cellobiose or glucose. Incomplete dissolving may be responsible for the high activation energy. Acetolysis is not so clear as that of pentosan.

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Studies reported on fabric abrasions, especially where the experiments by the abrasion tester is accompanied by the actual wearing test of the fabric are very limited. By comparing the results obtained from an actual wearing test with the results obtained from their UM type fabric abrasion tester, it was found that the results of simple laboratory testing, to a certain extent, parallel to those of the actual wearing test.
Though this method lacks sufficient reasons to be applicable to all cases with accuracy, it gives us a convenient means to presume roughly the actual resisting properties of fabrics to abrasion.

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The ideal contractive force of multifilament with circular section by twisting at a fixed length may be calculable by the following formula:
where n; total number of fiber, Px; load corresponding to the elongation at x(r/R) distance from the fiber axis, θx; twisted angle of fiber at the distance x from the fiber axis, nx; number of fiber in the coaxial cylinder with breadth dx at x distance from axis.
We found that the calculated and observed breaking strength by twisting at constant length are respectively 55g and 65g. These differences are approximately more due to the incomplete spiral structure than to the frictional effects, While the ratio between tensile strength and calculated breaking strength by twisting at constant length is 1.8, that of nylon and saran are respectively 3.0 and 3.8.
On the other hand, the same observed value of multifilament sized with 1% and 8% changes from 2.18 to 2.6 or 3.34 and approach to that of nylon and saran.
It seems reasonable to assume that contractive force by twisted single nylon filament at a fixed length is equivalent to that of a bundle of fiber beded by viscous medium.

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Usually, to obtain the dielectric constant of materials, one must measure the capacity increment of condenser due to the insertion of materials between its plates. Especially, in the case of the assemblage of fibers, the increment of capacity is much dependent upon the distribution of fiber direction. In the present paper, the author marks this point, and calculates the capacity increment by approximation. Some of the results are as follows:
1) When each fiber is perpendicular to the plate, the rate of capacity increment ΔC/C₀ becomes
2) When the fibers are parallel each other and to the plate, the rate of increment becomes
3) When the distribution functions are as follows: a) f(θ)=sinθ (where θ is the angle between the fiber and the normal of the plate), the rate of increment becomes b) f(θ)=constant (i.e., the direction of fiber is completely at random), the rate of increment becomes
Where ΔC is the capacity increment due to the insertion of materials, C₀ is the capacity of air filled condenser, ε is the dielectric constant of specimen, and ξ is the volume fraction of materials.
The experimental data, presented in this paper, show a very good agreement with the theory.

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