This paper deals with the false-twisting mechanism and the twist distributions of a yarn in both the twisting and untwisting zones using an air twister, which provides air-jet owing to air vortex.
In the case of using air-jet twister as shown in fig. 2 the twisting and untwisting phenomena are analyzed by taking photographs and the following results are obtained:
1) The twist of the twisting zone immediately propagates to the untwisting zone in the case of the nonexistence of solid contact which obstructs the propagation of the twist in the air-jet twister, and the twist of the whole zone into which the twist is able to propagate is observed to be the same direction as the twisting zone. The twist distribution is shown in fig. 10.
2) The yarn is rotated by the air vortex and makes the balloon, and its configuration becomes a complicated form which holds inherent balloons as the air pressure increases.
3) It is considered that the yarn rotates as if without contacting the twister and is twisted by the ballooning at the place of twister. It is so considered, because the yarn revolutions, as calculated under the considerations of the twist contraction and projective length, agree well with the balloon revolutions obtained from highspeed cine-photography.
4) The experimental values of, twist distribution in the untwisting zone meet well with that calculated from the theory of twist propagation, in which the yarn is considered to be viscoelastic.

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The microstructure of copper filament which was manufactured by the pyrex glass conjugated melt spinning under various winding speeds and cooling treatments was investigated and the following results were obtained:
1) On a scanning electron microscope, the etch pits on the strain figure along the fiber axis are found on polished samples. The distribution of the etch pits along the strain figure becomes dense as the winding speed increases. Such etch pits are not observed on the copper filaments subjected to the cooling treatment.
2) The lattice parameter (a), the stacking fault probability (α) and the line broadening are measured. Assuming that the line broadening is due to both the particle size (η) and the micro stress (σ), the maximum α and σ of the copper filament spun with various winding speeds are obtained. η decreases with increasing the winding speed. The maximum values of σ and η of the sample obtained by changing the cooling treatment are considered to reflect the combined effects of the tensile stress and the thermal stress produced by the rapid cooling treatment during the spinning. After electrolytically polishing the surface of the copper filaments, it is found that η increases with polishing time while a remains unchanged.

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A melt spinning experiment has been carried out to correlate breaking take up velocity with the molecular weight and to study the effect of melt temperature, ambient temperature and apparatus on the correlation. Samples chosen for study were ten iso-polypropylene samples having widely different molecular weight. The shape of breaking part and the birefringence of breaking filament have been measured. The results were as follows:
(1) A maximum in breaking take up velocity occurred in a certain value of molecular weight. A molecular weight in the maximum breaking takes up velocity increased with an increase in melt temperature. On the other hand, a strong correlation was observed between maximum breaking take up velocity and ambient temperature, and maximum breaking takes up velocity increased with an increase in ambient temperature up to 30°C. The effect of ambient temperature was closely related to the shape of breaking part.
(2) Breaking behavior was not affected very much by a type and scale of apparatus. The deformation length of breaking part increased with an increase in melt temperature and ambient temperature, and decreased with an increase in molecular weight. The shape of breaking part was affected by birefringence of breaking filament in low molecular weight, but in high molecular weight it was influenced by other factor, such as entanglement.

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In melt spinning of polypropylenes having various molecular weight, diameters of stream were measured along the spinning way by microscopic photograph. The distribution of extensional strain rate for distance from nozzle (dV/dX-X) was estimated from stream diameters. Its distribution curve has a maximum value which is increasing linearly with take-up velocity. The maximum extensional strain rate ((dV/dX)_max) in breaking was obtained by extrapolation to breaking take up velocity for each sample.
In the same manner with the exception of take-up, gravitational stressing spinning has been carried out. Relationship between load and fall velocity in gravitational stressing spinning was obtained for various samples. On the other hand, its relationship was theoretically estimated from equilibrium of forces using as a parameter
η^* (extensional viscosity). From comparison of both relationship, extensional viscosities of melt spinning were determined.
Tensile stresses in breaking_??__max were calculated by following equation;
Calculated values of tensile stress in this breaking remained over various molecular weight samples.

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The emissivity of polymers shows a remarkable change according to the variation of the repeating units. Since it is impossible to measure the monochromatic emissive power of polymers, the emissive phenomenon is investigated in terms of the infrared spectra of atomic vibrations as well as the distribution of blackbody emissive power.
The atomic vibrations contributing to polymer emission are assigned from the infrared absorption spectra. The atomic vibrations around the wave length λ_max yielding the maximum emissive power for blackbody emission contribute very effectively to the emissivity of polymers. On the other hand, such vibrations as stretchings of X-H, C≡X and C=X in short wave lengths as well as torsional, rotational and lattice vibration in long wave lengths are rather ineffective.
In general, emissivity is small if the molecules are composed of only C and H atoms and further their symmetry is excellent, whereas if they are composed of various different atoms or they have hydrogen bonding, their emissivity becomes large. Emissivity approaches to unity with the increase in the volume of polymers (i. e. with the increase in thickness of polymer films).

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On the basis of the conformational entropy and enthalpy for unperturbed polyethylene terephthalate (PET) and nylon 6 computed with restricted or unrestricted rotation about the skeletal bond, the thermodynamic quantity RTQ, the free energy difference between the crystalline and quasi-crystalline regions, was evaluated for several non-isomorphic PET and nylon 6 copolymers. Good agreement with experimental results was obtained. From the change of RTQ with X_A, mole fraction of major component, it is suggested that the rotation about skeletal bonds in the quasi-crystalline region (of major component) is more restricted with the increase of the content of minor component.

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In order to investigate the effects of the fine structure on the aminolysis of poly (ethylene terephthalate) (PET), PET films which have different annealing conditions and draw ratio were aminolyzed in 40%-mono-methylamine aqueous solution and 80%-hydrazine hydrate at 20°C.
Aminolysis rate decreased when PET films were crystallized. Aminolysis rate for amorphous regions of undrawn-crystallized PET films was independent on annealing temperature and was nearly constant. But aminolysis rate for crystal regions (k_c) decreased with increasing of annealing temperature. In this case k_c varied in proportion to the crystallite size.
When undrawn PET films were treated with fixed length under cold crystallization temperature (about 110°C) for 30min, aminolysis rate increased with increasing of annealing temperature. Maximum aminolysis rate was observed at annealing time of 1 hour when PET films were annealed with fixed length at 100°C.
Up to the draw ratio of 2.5, aminolysis rate increased with increasing draw ratio and over the draw ratio of 2.5 aminolysis rate became nearly constant.

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To clarify the internal texture of the drawn fiber made from milkcasein-acrylonitrile graft copolymer (PM-fiber), the microscopic observations were carried out by using the electron microscope and the optical microscope. The following results were obtained:
1) Skin and core layers are formed in the cross section of the fiber as well as the many characteristic “streaks” on the fiber surface.
2) Skin and core layers are distinguished only by the density of texture because in core layer the more micro voids are contained than in skin layer, but not distinguished by the ratio of milkcasein (MC) and polyacrylonitrile (PAN), crystallinity, the order and the orientation of crystalline part.
3) MC in PM-fiber distributes uniformly into the medium of PAN with the order less than 200Å. In the fiber obtained by blending MC and PAN, many aggregations of MC are observed as the column like particles with the about 1000Å length and the about 300-500Å diameter. From this facts the uniform distribution of MC molecule in PM fiber will arise from that MC-molecule uniformly dispersed into acrylonitrile (AN) monomer at the graft copolymerization process.
4) The difference is not found between the cross linked type and non-cross linked one of PM-fiber.

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To clarify the fine structure of the drawn fiber made from milkcasein-acrylonitrile graft copolymer (PM-fiber), the studies on X-rays diffraction and mechanical behaviors were carried out in the view point of comparison with those of polyacrylonitrile fiber (PAN-fiber) and milkcasein fiber (MC-fiber). The following results were obtained:
1) The fine structure of PM-fiber will consist of the many column like micro-fibrils parallel to the fiber direction, having no fluctuations of electron density in them because the small angle X-rays scattering pattern of PM-fiber shows only the same streak of equatorial direction as PAN-fiber.
2) X-ray diffraction curve of PM-fiber is similar to that of PAN-fiber and almost in agreement with the calculated curve from that of PAN-fiber and MC-fiber by considering the ratio of PAN and MC in PM-fiber.
From this fact it is found that the crystalline part of PM-fiber is formed only from PAN molecule and the crystalline properties such as the crystal structure, the orderliness, the size are scarcely affected by the presence of MC in the forming process of fiber texture.
3) Parallel model consisting of PAN and MC is deduced for the mechanical behavior of PM-fiber by the observation of two main peaks around 105°C and 240°C, assigned to PAN and MC respectively, in temperature dispersion of dynamic viscoelasticity.
4) The stress-strain curve of PM-fiber calculated from those of PAN-fiber and MC-fiber based on the above model is almost in agreement with the observed one in the non cross-linked type but not in agreement with the cross-linked one of PM-fiber.

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Dissolved state of cellulose diacetate in acetone was studied by means of gel-permeation chromatography (GPC), thin-layer chromatography and infra-red spectroscopy. Four peaks were detected in general in GPC elution curves named from lower count region prehump I, prehump II, mainhump, and posthump, respectively. Prehump I is attributed to the molecular aggregates of cellulose acetate with relatively high acetyl content (57-58%). This is principally equivalent to prehump in tetrahydrofuran found in the previous paper and is largely extractable with good solvents for cellulose triacetate. Prehump II is the molecular aggregates of cellulose diacetate having large molecular weight, which is closely connected with the contents of sodium, calcium and sulfuric acid. Prehump II can be removed by treating the sample with dilute acid solutions. Mainhump is due to the moleculary dispersed particles. The complicated dissolved state of cellulose diacetate in acetone, thus found, is ascribed partly to the distribution of degree of substitution (acetyl content) as well as molecular weight distribution and it is also due in part to the contamination of sodium and calcium as impurity and of sulfuric acid as combined ester in the original polymer.

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The hydrolysis of N, N'-dimethylol ethyleneurea (DMEU)-treated cellulosic fabrics in aqueous acetic acid was studied in comparison with that of the DMEU oligomers reported in the previous paper. The hydrolysis curves of the DMEU-treated cellulosic fabrics were divided into three steps in general, corresponding to the hydrolyses of N-CH₂OCH₂-N, Cell-OCH₂-N, and N-CH₂-N (including Cell-O(CH₂O)_n-Cell) links, respectively. From the combination of the hydrolysis data and other analyses of the treated fabrics, the amounts of the four links, that is, N-CH₂ OCH₂ -N, Cell-OCH₂-N, N-CH₂ -N, and Cell-O(CH₂O)_n-Cell links, were determined.
The hydrolysis of N-CH₂OCH₂-N and Cell-OCH₂-N links followed the first-order reaction, and the hydrolysis rates and activation energies of these two links were determined. In the case of unmercerized cotton, the hydrolysis did not follow the first-order reaction due to the diffusion effect when the samples were prepared with resin solutions of a high concentration, and the concentration of a resin must be as low as 3.2% in order to determine the amounts of the links by this acid hydrolysis method.
The amounts of the various links and the average lengths of the cross-links in the DMEU-treated cellulosic fabrics varied with the species of the cellulose used and the curing conditions. In most cases, the average length of the cross-links was from 2 to 2.5 ethyleneurea units.

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Nylon 6 fiber and filament were treated with butanol/water solutions of various compositions and change in the fine structure was studied from the measurements of shrinkage, density, and X-ray diffraction. Water absorption was also investigated as a measure of the internal effective volume.
Shrinkage, crystallinity, and crystallite size increased remarkably with the use of butanol/water mixture, compared to the treatment with butanol or water alone. Crystallite orientation decreased with the increase in crystallite growth. The effect was the same for the water absorption, suggesting the expansion of internal effective volume. The mixed solution was also effective for heat-set nylon 6 filament.

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The dyeing behavior of nylon 6 fiber in water/perchloroethylene emulsion was studied with reference to the change in the fine structure.
Fiber sample was dyed with 1, 4-diaminoanthraquinone from perchloroethylene after a pretreatment in water/perchloroethylene emulsion. Also the fiber was dyed with the dye in water/perchloroethylene emulsion without the pretreatment. In both cases, addition of a small amount of water to perchloroethylene caused a considerable increase in the dye absorption of the fiber.
The fine structure was investigated from the measurements of shrinkage, density, water absorption, and X-ray diffraction. The increase in the shrinkage, crystallinity, crystallite size, and water absorption were larger for the fiber treated with the emulsion than for the fiber treated with perchloroethylene alone.
These results are briefly discussed in terms of the changes in the fiber structure and the distribution equilibria of the dye between the fiber, perchloroethylene, and water.

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The diffusion of dye acid in polyamides (nylon 6 and nylon 12) was investigated by means of the cylindrical film roll method. The dye acids of C. I. Acid Orange 7, Blue 25 (monobasic), C. I. Food Yellow 3, C. I. Acid Blue 45 (dibasic) and C. I. Acid Red 18 (tribasic) were used. The diffusions of the dye acids in polyamides were determined at the dye acid concentrations between 1×10^-3 and 1×10^-4 mol/l, and at 90°C using infinite dye bath condition.
The diffusion profiles of dye acid in polyamide were assumed as mixed type which is consisted of Type F (Fickian diffusion) and Type I (box-like diffusion without ion-exchange). The profiles of the mixed type were analyzed to divide into the Type F and the Type I parts by modified McGregor's method.²⁾
The results are as follows:
1. The diffusion coefficient (D_F) for the Type F part was concentration independent.
2. The surface concentration (C^I₀) for the Type I part corresponded to the terminal amino group content for the polyamide. The diffusion coefficient (D_I) for the Type I showed a constant value at C<C^I₀, and the D_I increased with the dye acid concentration in dye bath.
3. The value of the D_I was greater than that of the D_F.
4. The values (D_F, D_I) of each dye acid in the nylon 12 were approximately one-tenth of that in the nylon 6.
It may be concluded that the diffusion of dye acid in polyamide occurs by two mechanisms, one of which is Fickian diffusion, the other is box-like diffusion without ion-exchange. These two mechanisms can operate independently but simultaneously. The contribution of the two diffusion mechanisms was discussed.

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In order to clarify various factors which affect thermal radiation of polymers, this series of studies have been made in relation to chemical structures, surface roughness, degrees of polymerization, crystallinity and melting of polymers. Results in this report show that the thermal radiation of polymers is very susceptible to the chemical structures; with the increase in sample thickness, the emissivity increases and approaches the value of blackbody.
Generally speaking, the emissivity of polymers with multiple bonds increases gradually with increasing thickness, while the emissivity of polymers without multiple bonds increases remarkably in a range of small thickness and levels off in the thickness more than about 50μ.
Among polymers containing fluorine, poly(vinylidene fluoride) has the largest emissivity while polytetrafluoroethylene has the smallest one and poly(vinyl fluoride) has an intermediate value.
The emissivity of polybutene-l is fairly low, being nearly equal to that of polypropylene.

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Morphological changes produced on the surface structure of Merino wool fibers by severe treatments with various alcoholic solutions of KOH in undehydrated and dehydrated systems were studied mainly by electron microscopy.
In the undehydrated systems results obtained were summarized as follows:
For the case of n-butyl or n-amyl alcohol of many monovalent alcohols used in this experiment, interesting phenomena were observed on the fiber surface, where the damage was localized within the cuticle regions during the treatment for 1 hr at 50°C. After the treatment with a 6% ethylene glycol solution of KOH for 1 hr at 50°C, the fibers were coiled and the scales were slightly suffered. In the glycerol solution containing 6% KOH, the chemical attack to scales was much accelerated at the temperatures above 50°C.
For the dehydrated systems, n-propyl and n-butyl alcohol were tested as the solvents. During the treatment with an 8% n-propyl alcohol of KOH for 2 hr at 50°C, descaling occurred and followed by degradation of the cortex. On the contrary, in the dehydrated system of n-butyl alcohol, descaled fibers were obtained for prolonged treatment without giving any perceptible damage to the cortical segments. The time of treatment required for descaling was of 17 hr and 40 hr with and without a mild agitation, respectively.

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The effect of medium on the Microwave heating has been studied for nylon 6 and polyester. Filaments lapped with a paper were impregnated with water, aqueous urea solution, benzyl alcohol, propylene glycol, ethylene glycol, diethylene glycol and glycerine, and heated 10 to 90 sec in a glass tube using a microwave apparatus (2450MHz, 550W). The change in the fine structure was investigated by the measurement of X-ray diffraction, density and stress-elongation relationship curve.
For both nylon 6 and polyester filaments, the microwave heating treatment increased the crystallinity and the crystallite size. Aqueous urea solution, glycerine, diethylene glycol, ethylene glycol and propylene glycol were more effective than water as media for the microwave heating.

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