The orientation function, F= (3<cos²θ>-1)/2, as a measure of the molecular orientation in acrylonitrile-methylacrylate copolymer fibers, was quantitatively expressed in terms of the X-ray diffraction intensity, infrared dichroic ratio or dye dichroic ratio.
This orientation function was introduced in the theory of photoelasticity in place of birefringence, and its relations to the draw ratio and stress in a fiber were obtained.
From the observed values of the orientation functions and their behaviors during drawing and thermal treatment, each orientation function was assigned to the specific part of the fine structure of acrylic copolymer fibers, i.e. the orientation functions obtained from X-ray diffraction, infrared dichroism and dye dichroism represent the orientation of crystalline region, overall orientation and amorphous orientation respectively.
It is likely that molecular slipping occurs in the course of drawing at higher levels of draw ratio, and that methylacrylate units in the chain disturb the lateral order of chain molecules during thermal treatment.

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In order to evaluate the magnitude of the molecular slipping of chains induced by stretching, anisotropic swelling of the acrylonitrile/N-methylolacrylamide copolymer crosslinked after stretching has been investigated. It was found that the magnitude of the molecular slipping increased with the ratio of stretching.
Relations of the degree of molecular orientation and the tension required for stretching to the ratio of stretching indicate that although the degree of orientation and the tension increase with the ratio of stretching, they reach to a constant value in the region of higher ratio of stretching. However, if the relation is plotted against the corrected stretching ratio (true stretch ratio) for which molecular slipping is corrected, the curve obtained is similar to the theoretical curve. Therefore, the deformation behavior of chain molecule is considered to follow the theory of rubber elastisity of non-Gaussian network.

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It has been established that the extent of crystallization of nylon 6 can be accurately followed by applying depolarized light intensity method for the specimens quenched in the course of crystallization. At the same time, it is shown that crystalline layer is often formed along the polymerglass interface in the crystallization above 120°C due to the enhanced interfacial inhomogeneous nucleation. But this was not the case in the crystallization below 100°C probably due to the increased nucleation within the specimen followed by slower growth rate of spherulites.
It is necessary to take into account the formation of the crystalline layer for getting correct information about crystallization in bulk by measuring the depolarized light intensity, which is much reduced by presence of the layer.

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Isothermal crystallization study of nylon 6 was made over the temperature range from 85°C to 180°C by measuring the depolarized light intensity through the specimens quenched at the various stages of crystallization as described in the preceding papers.
The Avrami's constant (η) determined by analysing the results of crystallization conducted above 100°C was 4, indicated that the spherulites observed under polarizing microscope were initiated by homogeneous nucleation, which was not in agreement with the result η=3 obtained by Magill. This discrepancy will be due to the fact that in the latter the depolarized light intensity was measured directly through the specimens brought to the desired temperature from the molten state, thereby were formed, in the process of cooling, embryoes acting as inhomogeneous nuclei.
The constants η for the crystallization at 90°C and 85°C were 6 and 5, indicating that the sheaf like growth was initiated, respectively, by homogeneous and inhomogeneous nucleation, which could not be discriminated by polarizing microscope due to the lack of resolving power. This phenomenon will be due to completion of the primary crystallization at the initial stage of sheaf like aggregation without further growing into spherulites. This is because that a large number of nuclei has been generated from the smaller critical nuclei with the lower crystallization temperatures.
At the same time, the dependence of growth rate of spherulites and overall constant of crystallization upon temperature was determined by measuring the diameter of spherulites. It has been shown that growth rate of spherulites, rate of nucleation and overall rate constant of crystallization are all systematized by the so-called law of ΔT^-1, meaning that the primary nuclei as well as secondary ones growing on the surface of spherulites are constant in their dimensions along the one direction irrespective of temperature.

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It is empirically known that there exists slip between a polymer and a die wall in polymer processing, but the analytical and the experimental treatment of this phenomenon have not been given sufficiently. In this paper, by studying frictional behavior between a tube wall and a polymer, we found the temperature region where the slip occurs. The ratio, γ=μ_s/μ_d, changes from γ>1 to γ<1 with increase of temperature, where μ_s and μ_d are coefficients of the static and slip friction, respectively. The critical temperature, T_f, at which γ=1 is 108°C, 165°C and 195°C, for medium density polyethylene, polystyrene and polymethyl methacrylate, respectively. Since the slip does not occur in the region of γ<1, μ_d in this region is not the external friction but intermal one. The temperature dependence of μ_d, in the region of γ<1, can be expressed by a single master curve T_f one choose the critical temperature, T_f, as the reference temperature. We obtained the following equation as the master curve at 20kg weight.μ_d= 0.11exp [-9.3×10^-3 (T-T_f)]

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Vinyl chloride has been grafted to high and low density polyethylenes by decomposing the peroxides and hydroperoxides, which were previously formed in the polymers by irradiating with γ-rays in the air. The influence of several parameters such as grafting temperature (55-100°C), preirradiation dose (1.27-5.23Mr) on the rate of graft polymerization, degree of covalent grafting, grafting efficiency has been studied. The experimental results are discussed and explained on the basis of the chain transfer to monomer and diffusion of monomer to polyethylene. The results are as follows:
a) Degree of covalent grafting lies between 40 to 100% depending on the grafting condition and kind of polyethylene samples.
b) The Arrhenius plots of the rate of covalent graft copolymerization exhibit a break point at 80°C, and the overall activation energy are 11kcal/mol above and 18kcal/mol below the point. Besides the overall activation energy of homopolymerization are 22kcal/mol.
c) Graft efficiency lies between 5 to 30% and the efficiency decreases as to the temperature increases.
d) Molecular weight of homopolymers formed in polyethylene has a similar value to that in liquid phase, and depends mainly on the grafting temperature.
e) An uniform distribution of graft concentration across the section is observed.

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Usually, the grafting ratio of styrene grafted rayon has been determined by its weight increase. But this method is not able to be applied to the styrene grafted cellulose systems, owing to the difficulty in accurate measurement of whole weight of grafted polymer produced by the pilot-, or industrial-plant. If the grafted polymer has a certain element either in its main chain polymer or in its branched polymer, such as N in polyacrylonitrile, it is easy to determine grafting ratio by its elemental analysis. In the case of styrene grafted cellulose, however, this method is not suitable. Therefore, the indirect determination of grafting ratio for styrene grafted rayon has been studied from certain characteristics of the polymer which vary according as the change of grafting ratio. For example, infrared absorption ratio, the specific gravity, and the amount of moisture regain were studied. It was found that these methods were very useful and convenient for the determination of the grafting ratio for the products and its distribution in the industrial scale reaction vessel, from the point that easy and quick determination is available with high precision. Infrared method applied for pilot plant products is shown as an example. Some other methods have been studied such as water absorption, dyeability and the dielectric constant, but any satisfying result could not be obtained on these methods.

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Radical copolymerizations of 3-chloromethyl-3-allyloxymethyl-oxetane (CAO) with vinyl acetate (VAc), styrene (St) and maleic anhydride (MAH) were carried out. The behaviors of the polymerizations and some properties of the copolymers obtained were investigated. CAO and VAc could be easily copolymerized and copolymers of various compositions were obtained. The monomer reactivity ratios at 65°Cwere γ_CAO=0.22±0.01 and γ_VAc=1.36±0.01. For CAO-Stsystems, it was difficult to obtain copolymers having large CAO contents. From these results theQ-e value of CAO was calculated as follows: Q=0.030 and e=-1.40. Copolymerization of CAO and MAH proceeded very smoothly. From the results of the analyses of copolymers, it was suggested that CAO-MAH copolymer had an alternate structure. All copolymers obtained were soluble in various organic solvents, but, by treating with boron trifluoride etherate, CAO-VAc and CAO-MAH copolymers became insoluble.

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Cationic copolymerizations among styrene, indene and benzofuran have been carried out. Monomer reactivity ratios in various solvents and with catalysts at 30°C have been determined. The relative reactivities of these monomer toward styrene carbonium ion were found to be, Indene>Benzofuran ≥Styrene
1.5-4 1-2 1
In contrast to the slower rate of homopolymerization of benzofuran than that of styrene in the previous paper, this enhanced relative monomer reactivity of benzofuran in the copolymerization might be possibly due to preferential solvation of benzofuran to the propagating carbonium ions.
The examination of the effects of solvents and catalysts on the copolymer compositions gave theresults that a comonomer expected to have larger solvating power (benzofuran>indene>styrene) was incorporated into the copolymer more favorably in non-polar solvent than in polar solvent and that the increase of the activity of the catalyst decreased the selectivity of the propagating carboniumion toward comonomers.

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The copolymerization of methyl N-carbamyl-maleamate with styrene was carried out in dioxane at 70°C. The monomer reactivity ratios were found to be 1.45 (γ_s) and 0.0 (γ_m).
Alkaline hydrolysis of the copolymer was carried out in dioxane-methanol at 60°C. The saponification products of the copolymers consisted of maleimide unit, maleamic acid unit and styrene unit.

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The effects of ethers such as di-n-propyl ether, di-n-butyl ether, di-n-hexyl ether and of triethylamine on the polymerization of styrene by Et₃Al-β-TiCl₃ catalyst were investigated stoichiometrically. It was found that the rate of formation of isotactic polystyrene was increased remarkably by the increasing amount of ether and showed maximum at the molar ratio of Ether/Et₃Al=1. At the greater ratios the rate was rapidly decreased. The increase in rate by the additive compound was found to be in the order of Et₃N<(n-C₃H₇) ₂O<(n-C₄H₉) ₂O<(n-C₆H₁₃) ₂O. The increase of polymerization rate was mainly ascribed to the increase in the number of stereospecific active center on the catalyst. It is known that the catalyst is deactivated gradually by the excess of Et₃Al during the polymerization reaction. The additive compound used may suppress the deactivation by the complex formation with Et3Al. This must be the cause of the apparent increase in the number of active center. Investigations were also carried out on the effect of n-butyl ether on the polymerization of styrene by Et₂AlCl-β-TiCl₃ catalyst. The rate of formation of isotactic polystyrene was similarly increased with increasing amount of the ether and gave a maximum at Ether/Et₂AlCl=1. This increase in the rate may be attributed to the increase in monomer concentration participating in the stereospecific polymerization as a result of inhibition of cationic polymerization by the complex formation of n-butyl ether with Et₂AlCl in the catalyst system.

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New polyamide was prepared by the polycondensation of prepolymer obtained in methanol by the reaction of dimethyl terephthalate and mixed aliphatic diamines, which were derived from the telomers of ethylene and cyanogen chloride. This polyamide melted at 225-235°C.
Polymerization conditions were investigated to get a polymer having a good melt-spinnability.
Solubility of this polymer lay between that of polycapramide (Nylon 6) and poly (ethylene terephthalate), and Young's modulus of the fiber obtained from melt-spinning was higher than that of polycapramide as it was expected.

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The melting point of polyamide prepared by the aminolysis reaction of dimethyl terephthalate with mixed aliphatic diamines was about 20-25°C lower than that of polyamide obtained by nylonsalt method. The both polyamides had been considered to be same structure each other.
It was proved that the melting point depression of polymer was caused by partial N-methylation on the amide linkages through the prepolymer formation and that the N-methylation was due to the slow rate of aminolysis.
Diphenyl terephthalate, which was more reactive intermediate, was employed instead of dimethyl terephthalate for the polyamide synthesis.
The prepolymer obtained had much higher molecular weight than the prepolymer from dimethyl terephthalate and was free from the secondary amine unit. Melt polycondensation of this prepolymer afforded a high molecular weight of polyamide melting at 245-258°C which also was free from N-methylated group and gave good fibers by melt-spinning.

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It is studied whether N-vinylcarbazole can be polymerized in solid phase by Friedel-Crafts catalysts, such as SnCl₄, AlBr₃ and FeCl₃. Poly-N-vinylcarbazole can be obtained in the solid phase polymerization even by a solid catalyst, such as AlBr₃ and FeCl₃, as well as by liquid catalyst (SnCl₄) or gaseous catalyst (BF₃). In the solid phase polymerization by these Friedel-Crafts catalysts, it is found that a monomer crystal partially melts at the temperature lower by 10-15°C than the melting point of pure monomer, and at this point the molecular weight of the polymer and the rate of polymerization abruptly increase. In the range of temperature where polymerization can proceed in the solid phase, the molecular weight of the resultant polymers is very low (ηps/C: 0.035-0.045) and the kinds of catalyst and polymerization temperature do not affect the molecular weight of the polymer. It is considered from these results that the arrangement of monomer molecules controls the molecular weight of the polymer in the solid phase polymerization.

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It is found that N-vinylcarbazole can be polymerized in the solid phase by vapor of halogen (I₂ Br₂ and Cl₂) which has a low activity for the cationic polymerization of vinyl monomers. The product is identified to be poly-N-vinylcarbazole from IR spectrum and elemental analysis. Molecular weight of the polymer obtained in the solution polymerization decreases in the following order; I₂>Br₂>Cl₂.On the other hand, in the solid phase polymerization, molecular weight of the polymer is low and independent of a kind of halogen. This behavior is the same as that of a metal halide catalyst. The rate of polymerization in the solution polymerization decreases in the order of I₂>Br₂>Cl₂. However, in the solid phase polymerization, the activity of a catalyst is different from the solution polymerization as follows; I₂>Cl₂>Br₂. This fact shows that in the solid phase polymerication the activity of a catalyst depends not only on the chemical character but also on the molecular size.

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The redox reaction of NH₂OH and TiCl₃ proceeded by radical process and this redox system initiated the polymerization of vinyl monomer (MMA) and gave amino-group containing polymer. From the consumption of Ti³⁺ (NH₂OH), the N content of polymer and molecular weight, the number of amino group per polymer molecule was estimated to be about 2.
It was found that the initiation reaction proceeded by NH₂ radical, and the termination reaction occurred dominantly by coupling or primary radical termination.
It is considered that this sytem would be one of the effective method for the introducing of amino-group to the end of polymer.

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