This research has been done with the object of modifying the hydrophobic property of the polyethylene terephthalate (PET) fiber. Acrylic acid was graftpolymerized with benzoyl peroxide (BPO) initiator onto the commercial PET fibers pretreated with benzyl alcohol.
Since original commercial PET fiber has a poor graftreactivity, the fibers were pretreated with benzyl alcohol (150°C, 1 hr) as the swelling agent to increase its reactivity.
The graft-polymerization was carried out in aqueous solutions of various compositions containing BPO as the initiator, polyoxyethylene nonylphenylether (nonionic surfactant) as the penetrating agent, and acetic acid, dimethyl formamide, Na-acetate, Na-acrylate or pyridine as the pH modifier of the reaction medium. The presence of 1_??_3% of nonionic surfactant in the reaction medium increased the grafting per cent of acrylic acid onto the fiber up to 2_??_4 times. The presence of pH modifier in the reaction medium affected the grafting. When the graft amounts were plotted against pH they had the maximum at 2.5_??_3.0 for various compositions of the reaction media.
Ca salt of graft copolymer was isolated from dichloroacetic acid solution of the fiber by precipitation and extraction. Infrared spectra of the Ca salt of graft copolymer showed absorption at 1570cm^-1 for carboxyl anion, and 1110cm^-1 and 875cm^-1 for phenyl group.

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Glycidyl methacrylate (GMA) was graft-polymerized upon undrawn polyethylene terephthalate (PET) fiber and commercial PET fiber, in order to improve their dyeability utilizing the reactivity of its epoxy-ring with dyestuffs which have phenolic hydroxyl or amino groups.
The graft reactions were carried out in aqueous solutions of dimethyl formamide (DMF) in which benzoyl peroxide (BPO) as the initiator and GMA as the monomer were dissolved.
Since the commerical fibers has a poor reactivity the fibers was treated with benzyl alcohol at 150°C for 1 hr. preceeding the graft-polymerization.
In the media of aqueous DMF, the graft polymer of GMA was given rise to opening of the epoxy-ring by water. At the content of DMF below 80% in the aqueous solution, the rate of the ring-opening increased with increase of water content in the solution, giving rise to gelation by cross-linking or net-work formation between hydroxyl formed and epoxy groups. It was difficult to extract the homopolymer, giving rise to a over estimation of the apparent grafting per cent of GMA. At the content of DMF above 80% in the solution, no ring-opening occured and the grafting per cent of GMA, measured from the weight increase of the sample, coincided with that estimated from the epoxy value. The graft reaction was, therefore, carried out in the 80% DMF solution in water.
The grafting per cent of GMA, measured at a certain reaction time, varied with BPO concentration and had a maximum in the range of 0.005_??_0.01 mol/1 of BPO.
The activation energy for the grafting is estimated as 14.7 Kcal/l for both the undrawn and the pretreated commercial PET.
Mechanical properties such as tenacity, yield value, initial modulus and elongation of various grafted samples of the pretreated commercial PET were unchanged by the grafting. Dyeability of the grafted undrawn and commercial PET was examined by the use of Orange II. The ungrafted fibers lack dyeability. On the other hand, the dyeability of the grafted fibers increased with the increase of the grafting per cent of GMA. Orang II may react with the epoxy group of the graft polymer in pyridine. No decolorization of the dyed samples took place both in hot water and in pyridine.

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It was found that wet-spun polyvinyl alcohol (PVA) fibers whitened when they were hot-drawn to the constant draw ratio before breaking. In order to investigate the relation between the mechanism of whitening and the fine structure of whitened fibers, PVA fibers were drawn at various temperature and draw ratio, rate of drawing, tensile strength, visible ray transmittance, X-ray small angle scattering power, crystallinity and crystalline orientation of hot-drawn fibers were measured.
1) It was concluded that periodic transverse lines of whitened fibers observed with a optical microscope are row of macrovoids which appear only in dense parts of cross sections. Creases on the surface are observed with a scanning electron microscope.
2) Changes of tensile strength and crystalline orientation by hot-drawing are correlative with that of visible ray transmittance. It was suggested that macrovoids which occured in fiber disturbs the structure.
3) Conditions of hot-drawing, temperature, rate of drawing and medium have a important effects upon the whitening points. From these results, the mechanism of whitening were discussed.

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In this paper, the simulation for the polypropylene melt spinning was done to presume the birefringence of the spun filament by use of the results obtained in the previous report ⁷⁾.
By taking into consideration of the heat balance and Trouton viscosity (tensile viscosity), the changes of filament temperature and its attenuation, and the spinning tension were calculated for given spinning conditions. From these results, the development in birefringence along the spinning line were presumed. The results agreed well with those observed in actual polypropylene melt spinning.
Next, the calculations of the spinning condition (melt temperature) for the desired filament birefringence were carried out with a satisfactory result.
Last, the effect in asymmetric cooling resulting from the transverse air flow for a filament axis were calculated on the distributions of the temperature and birefringence. The temperature distribution in the filament cross-section was obtained by solving the basic equation of the filament thermal conduction by means of finite-difference method, and the birefringence distribution was then estimated from its temperature distribution. This result is considered to be effective to analyze the latent crimp of the filament.

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Void size distributions of wet-spun acrylic fibers were studied by means of mercury porosimetry, X-ray small angle scattering and combined measurement of surface area and density:
1. Measurements of the porosimetry revealed that first the void size distributions depend on the polymer compositions; the peaks of the distribution curve are at the radii of about 1000 A for fibers from acrylonitrile (AN) and methyl acrylate (MEA) copolymer, about 400 A for polyacrylonitrile fibers and fibers from AN, MEA and styrene sulfonate (SSS) terpolymer, about 100 A for fibers from AN and SSS or allyl sulfonate (SAS) copolymer, secondly the position of the peak shift to the small radius by stretching.
2. The results obtained from the X-ray small angle scattering based on Fankuchen's method are similar to that obtained by porosimetry.
3. Assuming that the frequency distribution of the void size takes gamma distribution, the mean radius (R_??_) and the number (N_??_) of the spherical voids are obtained by the following equations. where p is a parameter of gamma distribution function, d₁ is toluene density, d₂ is mercury density, A is surface area of fibers.
Using the relationship between gamma distribution and x² distribution, volume fraction of voids having radii larger than a certain value (Pr) can be estimated.
4. The results obtained from applying the analytical method mentioned at (3) are as follows; first, R_??_is nearly equal to the radius at which void size distribution curve from porosimetry takes a maximum value. Secondly logarithm of the number of voids having smaller radii than 1000 A is linearly related to the X-ray small angle scattering power.

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The melt spinning of copper was investigated by using an experimental apparatus devised according to Wagner's patent, and the following results were obtained:
a) The strength of copper filament increases with decreased cross-sectional area of the filament and with increased winding speed.
b) The effect of melt spinning on the internal structure of copper filament is as the same as cold drawing of copper rod; it has been confirmed that the crystal plane (200) tends to arrange parallel to the fiber axis.
c) The fiber axis of copper filament, prepared by melt spinning, is <100> or <221> plane, the former orientation being predominant.
d) From the viewpoint of practice, the evolution of gas during the spinning which gives rise to defects in the fiber is a problem to be solved.

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