In the previous paper¹⁾, the relationship between necking characteristic factors and neck angle which is a parameter expressing the characteristics of the necking geometry were discussed for undrawn polyester fibers.
The present paper intends to investigate the drawing mechanism of polyester fibers on the basis of the informations obtained in the previous paper.
1) The results obtained in the most ideal drawing system equipped with the hot-pin leads us to conclude that substantial conditions for occuring necking are hot-pin temperature and feed roll speed. The necking angle is affected decidedly by these factors, and the necking properties such as. draw ratio and necking tension, are determined only by the necking angle.
The necking draw ratio is not equal to the machine draw ratio defined as the speed ratio of two rollers. The relationship between the necking draw ratio and the machine draw ratio may be expressed by following equation:
Machine DR=Necking DR+2nd draw
2) The neck angle estimated from the model undrauring using WLF equation agrees well the experimental results.
3) The experimental relationship between the necking drawing and 2nd drawing is discussed for the model and industrial drawings.
4) The neck angle is closely related to the aging condition of the undrawn polyester fibers.
The increase of aging time enlarges the neck angle and the local variation.

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The evaluation of crystalline and non-crystalline orientation factors of PVA film from the data on x-ray diffraction, infrared dichroism, and birefringence is performed, and the following conclusion are obtained:
(1) By using experimental result of the infrared dichroism and x-ray diffraction analyses, infrared transition moment angle of a crystalline absorption band can be determined quantitatively The crystalline orientation factor of a uniaxially stretched PVA can be determined quantitatively from infrared dichroism measurements. The transition moment angles Θ_j, to the crystalline chain axis for the 1141cm^-1 band are 81°25′ and 83°25′ for samples annealed at 160°C and 90°C, respectively.
(2) The non-crystalline orientation factor com be determined from infrared dichroism of the uniaxially stretched PVA films dyed with Congo Red, by compensating method using non-dyed films The infrared dichroic orientation factor F_{am, (I. R)} for the 755cm^-1 band is in agreement with the non-crystalline orientation factor F_{am, (Bir)} calculated by assuming that the additivity of birefringence is valid.

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Dichroic value of poly (ethylene terephthalate) (PET) and polypropylene (PP) films dyed with C. I. Disperse Yellow 7 was measured at high temperatures in order to investigate the influences of draw ratio and temperature of stretching on the thermal change of the dichroism.
When the break appearing in the plot of D versus temperature was plotted against the D measured at room temperature, a linear relation was observed. This leads us to conclude that the glass transition temperature of PET rises linearly with increase in the degree of amorphous orientation.
As for the PP film the following results were obtained:
(1) Three transition points were observed above T_g at T₀ (38_??_50°C), T₁ (74_??_85°C) and T₃ (108_??_120°C).
(2) T₁ and T₃ are nearly constant independently of the value of D, while T₀ drops at first and then rises with increase in D through a minimum value at D=0.7_??_0.8.
(3) T₁ and T₃ decrease systematically with increase in the content of atactic fraction, hence, tacticity has a great influence on the mobility of PP segment.

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The amorphous orientation of linear polyethylene (PE) was investigated by a dye dichroism method using a fluorescent dye, Whitex. Inflation films of linear PE (Sholex-6000) were drawn in hot water at 60°C and then dyed for the subsequent measurement of dichroism. The value of φ_D, defined by φ_D=(D_{_??_}-D_⊥)/(D_{_??_}+2D_⊥), were determined for the samples drawn to various ratios, and compared with the amorphous orientation factor f_a derived from the birefringence and the crystalline orientation factor f_g determined by X-ray method.
In the relatively lower range of draw ratio, the φ_D agrees well with f_a, i.e., f_a≅φ_D. Thus the dicroism orientation factor f_D defined byf_D=φ_D/φ_D° can be obtained by putting φ_D°=1, where φ_D° is the value of φ_D coresponding to the perfectly uniaxial orientation. In the case of highly drawn specimen, the relation between φ_D and f_a differs from that obtained in the lower draw ratio.
This indicates that the does dichroism dres not reflect precisely the orientation behavior of the amorphous region in the highly drawn specimen, suggesting that the sites of dye absorption are not only in the amorphous region but also on the surface of fibrils resulted from the higher drawing.

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Dyeing behavior of disperse dyes on KURARAY ESTER (KES), a polyester fiber containing methoxypolyethylene glycol (MPEG) as a co-monomer, was investigated.
As dyeing mechanism of disperse dyes on KES and polyethylene terephthalate fiber (PET) is due to the partition law, it is considered that the amorphous region plays a role as a solvent for the dyes.
Accordingly, it is proposed that the degree of amorphism of fiber should be introduced into T. G. Majury's equation as a correcting term to calculate affinity.
Increase in MPEG component results in the increase of affinity, heat of dyeing and diffusion coefficient, the decrease of entropy change (for convenience, the value in Fig. and table is shown as -ΔS° and activation energy of diffusion.
It is pointed out that this tendency is mainly due to the characteristics of configuration and rheological properties of the amorphous region.

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