The variation of creep and creep recovery with temperature, and the ultimate properties under a condition of constant load have been measured for acrylonitrile-methylacrylate copolymeric fibers composed of different molecular weights. In the experiments of creep and creep recovery, the response against external force becomes sensitive with decreasing molecular weight. It is assumed that the response against external force is determined in the relatively low ordered region formed around the end points of molecular chains. In the creep rupture experiments, the following results are obtained. The effects of the molecular weight are clearly observed at the rubbery or leathery zone of the compliance at break and the increase of molecular weight makes the leathery zone shift towards longer times if a reference temperature is fixed at a constant value. In the temperature region approximately from 80 to 130°C; the temperature dependence of the shift factor a_T along the logarithmic axis of the time to break is unaltered and independent of the molecular weight. The composite curves of the logarithmic tensile strength plotted against the logarithmic time to break exhibit an identical shape, where the composite curves are obtained from the measurements in the same temperature region stated above. In contrast, the temperature dependence of a_T approximately above 130°C and the composite curves of the tensile strength obtained at the corresponding temperature region show different behaviours in accordance with the values of the molecular weight. The maximum value of the ultimate elongation decreases with increased molecular weight. These effects of molecular weight may be explained in terms of “doubly bonded structure” discussed by Andrews and Kimmel.

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Laps of parallel-laid webs were used as materials and hardened by the plate hardening machine. During this process the area of laps showed practically no change, but their breaking strength by g/tex unit remarkably increased. These facts may be due to an increase of inter-fiber bonds in the direction of thickness of laps.
The plot of breaking strength vs. hardening time showed a sigmoidal-curve. This may be explained by a sharp increase of interlocking in an early stage of hardening process and a gradual increase of resistance for compression in the later stage.
Lateral breaking strength of the hardened felt is always lower than longitudinal one, while the ratio of the both strengths increased from 0.25 to 0.55 by hardening. This increase of the strength ratio may be due to an increase of fiber orientation in the width direction of the hardened felts. A prolonged hardening of felt is undesirable from the point of view of the quality of products.

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The effect of uni-axial compression force during hand milling on the milling behaviours of wool felt was investigated. When milling force is applied to the length direction, the felt shrinks remarkably in this direction, while there is little or no shrinkage in the width. In this case, fibers in wool felt are re-orientated into the width direction with the progress of milling.
The breaking strength of the milled felt is greater in the width direction than in the length, while the breaking extention works opposite from this.
This may be caused by the fact that the fiber orientation in the width direction is higher than that in the length.
On the other hand, when milling force is applied to the width direction, the felt shrinks mainly in this direction, fibers in the felt are re-orientated into the length direction, and the breaking strength of the milled felt becomes higher in the length direction than in the width.
The longitudinal and lateral breaking strengths and breaking extention of the felts with the same degree of area shrinkage are little affected by the milling courses, but evidently affected by the degree of length and width shrinkage of the felts.
The felt of proper shrinkage of length and width showed nealy the same breaking strength and extention in longitudinal and lateral directions.

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The shrinkage of hardened felt during milling process was studied using a roller type milling machine. Relations between dimentional changes such as length, width and thickness in milling process and breaking strength, breaking extention and splitting resistance of the milled felt were also examined.
Up to 30-35% shrinkage of area (SA), contraction of the felts is caused mainly by the shrinkage in longitudinal direction. Above this AS, the rate of area shrinkage of the milled felts distinctly slows down, while the rate of shrinkage in width increases and thickness begins to increase. At this SA (30-35%), breaking strength of milled felt shows the maximum value, while its breaking extention shows the minimum value. Splitting resistance rises as SA is increased, and the rate of the increase becomes evidently larger above 30-35% of SA.
Assuming that breaking strength and splitting resistance are mainly affected by the degree of entanglement of wool fibers and the degree of fiber orientation, the experimental results are deduced that the degree of fiber orientation in the vertical direction would increase over 30-35% of SA.

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The yellowing work of H₂O₂ produced by exposing aqueous tyrosine, tryptphane and their mixed solutions to light was studied.
First, from the spectro-trasmittance of these amino acid solutions added and without H₂O₂ in advance, exposed to the light emitted by the weather meter for various time intervals, the dominant wavelengths corresponding to hue of these solutions was determined.
As the results, the dominant wavelengths of these solutions with H₂O₂ were similar to these without H₂O₂. In regard to the yellowing speed of the mixed solutions with H₂O₂, the empirical formula as to function existing between percentage transmittance T (%) or luminosity Y (%) and exposure time t (hr) is well represented by our familiar formula of the mixed solution without H₂O₂, that is, T (Y)=a (t-k)^-b. But in this case the additional constant k equals zero. And so, as soon as it is exposed to the light it makes an appearance of color. Next, the produced quantities of H₂O₂ and the yellowing by exposing of these amino acid solutions to light for various time intervals were examined.
In consequence, H₂O₂ yields are closely connected with the yellowing degree, induction periods and photosensitization of these solutions. Accordingly the yellowing of tyrosine and tryptphane series by light are dominated by H₂O₂ yield as the initiator of coloring.

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The wetting behavior under various pressures of loose fiber assemblies were examined and the results were compared in order to estimate the water-resisting properties of various commercial proofing methods. This procedure was considered to throw some light on the penetration mechanism of water into fabrics in the direction perpendicular to the surface. In this article, measurements on the degrees of penetration of distilled water in the assemblies of non-proofed fiber are reported, changing the types of fiber, the porosities of assemblies (degrees of openings) and the hydro-static pressures. Porosities of the assemblies were 70, 80, and 90%, and the hydrostatic pressures 15, 40 and 65g•wt/cm². The rate of movement of water front downward through the assemblies was measured and the primary water-resisting index was calculated from this. The rate of flow of water (volume per unit time) was obtained after the water front had reached the bottom of the assemblies and then the secondary water-resisting index was calculated.
Remarkable difference in these two indices was found in the different types of fibers in the case of the same porosity and pressure. The water-resisting effect of the assemblies of synthetic fiber is very small compared with that of cellulosic fibers. It may be pointed out, therefore, that an effective water-proofing finish is required in the synthetic fiber fabrics which are subjected to hydrostatic pressure.

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