The mechanical anisotropies of uniaxially stretched polyvinyl alcohol films were investigated experimentally and theoretically in relation to the orientation of crystallites and noncrystalline chain segments. The theoretical calculations of Young's modulus were carried out on the basis of both the homogeneous stress and the homogeneous strain hypotheses, using two types of structural model. One of them was made up by averaging the aggregation of structural units composed of the orthorhombic crystalline and the isotropic noncrystalline phases under consideration of their orientation distribution and their mechanical constants. On the other hand, the mechanical anisotropy was evaluated for the structural model which is constructed by combinning the averaged crystalline with the averaged noncrystalline phase.
The calculation on the basis of the homogeneous stress hypothesis using either structural model gives a considerablly good agreement with both the observed Young's modulus parallel and perpendicular to the stretching direction of the uniaxially stretched film. However, the calculation on the basis of the homogeneous strain hypothesis using the structural model gives results higher than the experimental ones in parallel to and lower than those perpendicular to the stretching direction, respectivelly.

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The mechanical anisotropies (Young's Modulus) of orthogonal- biaxially stretched PVA films, such as simultaneous, strip and two-step, are investigated experimentally and theoretically, and discussed in terms of the orientation of crystallites being intrinsically anisotropic in mechanical properties.
The theoretical results were obtained by means of the calculation, on the basis of both the homogenous stress and the homogenous strain hypothesis, for averaging the aggregation of structural units composed of crystalline and noncrystalline phases.
The comparison between the experimental results and those calculated for each of three types of orthogonal-biaxially stretched films indicates the following:
1) The experimental data of Young's modulus for simultaneous-biaxially stretched films are located between those calculated theoretically in two extreme cases on the basis of the homogeneous stress and the homogeneous strain hypotheses. On the calculation, the preferential orientation of the plane-normal vectors around the crystalline chain axis was considered.
2) The calculated Young's modulus of strip-biaxially stretched films based on the homogeneous stress hypothesis are rather close to the observed.
3) The change of Young's modulus of two-step-biaxially stretched films accompanies with the draw ratio λ₃ and λ₂ along two principal stretching directions. The calculated Young's modulus based on the homogeneous stress hypothesis follows to the change of the observed Young's modulus with draw ratio λ₃×λ₂.

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Wet-spinning processes of polyvinyl alcohol (PVA) fibers are studied in relations to the phase equilibrium and the composition of multi-component systems consisting of polymer, solvent and nonsolvent. The relation between the path of composition change along the spinning line and the structure of undrawn fibers, is discussed.
Water and dimethylsulfoxide were used as solvent; and sodium sulphate, caustic soda, also their mixture and methanol as a precipitating agents. Boric acid is added to one of spinning solutions as gelation agent.
The ratio W_S/W_N (W_S, is the weight of solvent transfered from fibers into spinning bath, and W_N, that of the nonsolvent transfered from the bath into fibers) determines the path of composition change, and is independent of the concentration of precipitating agent in the bath.
Initial moduls and temperature of the _??_ a dispersion in plot of tanδ for undrawn fibers decrease with increased W_S/W_N. It is pointed out that W_S/W_N affects the concentration of cross-links and the drawability of undrawn fibers.

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Crystallization was studied for wet-spun polyvinyl alchol (PVA) fibers prepared by various paths of composition change for which the ratio W_S/W_N, (W_S, the weight of solvent transfered from fibers into spinning bath and W_N, the nonsolvent transfered from the bath into fibers) is the determing factor. Crystallinity index proposed by Wakelin was determined for the fibers by uses of the freeze-dried iso-PVA and single crystal of synd-PVA as the standard samples. Crystallinity indexes of PVA fibers obtained by this method are related closely to their resistance to hot water. This technique is also effective in measuring crystallinity of fibers on heating and cooling. The crystallinity index is not equal to the crystallinity determind from the intensity of halo on meridian, since the intensity of halo on meridian depends on orientation of amorphous chains.
It can be concluded that crystallinity of wet-spun PVA fibers increases with decreased W_S/W_N on spinning processes.

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The deformation were examind in PET filaments drawn at various conditions in which the drawing temperature, draw ratio and strain rate varied. When drawn filaments were bent repeatedly at room temperature or at elevated temperature, deformation bands appeared in the compressed side of the filaments.
Deformation bands appeared easily in the speciments of higher orientation and lower crystallinity at room temperature. As the crystallinity of the filaments increased by heat treatment, repeated bending for the appearance of deformation bands at room temperature increased. But when these filaments were bent at about 200_??_220°C, sharp bands appeared after a few repetation of bending.
The deformation bands formed at room temperature had little or no influence on the tensile properties of the filaments, but those formed at 200_??_220°C lowered significantly the breaking strength and the elogation of the filaments. In this case, cracks initiated at the deformation bands and propagated along these bands.

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The energy method, used for the derivation of the tensile properties of continuous filament yarns by L. R. G. Treloar and G. Riding and by J. W. S. Hearle, is applied to the compound filament consisted of cocoon fiber and TETORON (PET filament).
The tensile stress as a function of strain is expressed by the following equation:
Where f_y (ε_y): stress of the twisted compound filament at a strain of ε_y
m_s: total denier of cocoons
m_c: denier of core filament
M=m_s+m_c
F_s: stress of cocoon fiber that is a function of the strain ε_s and determind experimentally from its s-s curve.
F_c: stress of core filament which is a function of the strain ε_c and determined experimentally from the s-s curve.
K=∂ε_s/∂ε_y
ε_??_=(β-γ)/(1-β)
β: the twist-shrinkage of the compound filament
γ: the twist-shrinkage of TETORON
The s-s curves of cocoon fiber and TETORON and the twist-shrinkages of TETORON and the compound filament are introduced into this equation. The satisfactory agreement is found between the results calculated and observed. From this result, it may be said that the tensile behavior of the twisted compound filament is accounted satisfactorily by the above equation.

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Light resistance of polypropylene (PP) and nylon 6 fabrics, grafted with acrylic acid and then treated with aqueous solutions of some metallic salts or tris (1-aziridinyl) phosphine oxid (APO), was studied by evaluating the retention of warp tensile strength of the fabrics after exposure to xenon arc lamp or sunlight.
Larger loss in strength of original untreated PP fabric after exposure as a result of the extraction with benzen may be explained by the removal of included stabilizer by the extraction.
Grafting of acrylic acid onto PP fabric and further treatment with aqueous solution of metallic salts cause unfavorable effect on light resistance due to the presence of carbonyl groups in the grafted side chains.
The most effective method to improve the light resistance of acrylic acid grafted PP fabrics is the after-treatment with APO. The higher the percent grafting or/and concentration of APO treating solution the better resistance is attained.
On nylon 6 fabric, nearly similar results to the case of PP fabric are obtained by grafting and treating with metallic salts, but the effect of APO is not crear with acrylic acid grafted nylon 6 fabrics as the add-on of APO is not so high as the case of acrylic acid grafted PP fabrics.

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