New polyamides having pyridine rings were prepared by the polycondensation reaction of pyridine 2, 5-dimethylamine with dicarboxylic acids of carbon number of 5 to 10. All of the polyamides obtained here melted at 178-255°C, and had good melt-spinnability. Copolymers were obtained by copolycondensation of hexamethylene-diammonium adipate and pyridine-2, 5-dimethyl-diammonium adipate in various molar concentrations of the component. The copolymers obtained here melted at 218-255°C, and also had good melt-spinnability, and the melting point of the copolymer has a minimum value in a definite molar ratio of the component.

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The insoluble powder like condenastion polymers were prepared from dimethylolurea, N, N′-bis (methoxymethyl)-urea in acidic solution by regulating the concentration of reactants at room temperature. The elementary analysis of the polymer was carried out andthe combined formaldehyde was estimated. As the results, it was found that these polymers have branching structure, and that the mole ratio of urea/formaldehde in polymers increases with decreasing the initial concentration of each reactant. These phenomena would beexplained by the reaction mechanism described in previous papers.

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Methylvinylmaleate and fumarate were synthesized by Vinyl Interchange Reaction of vinylacetate with monomethylmaleate or fumarate and their physical properties were determined.
The cyclization polymerizations of above monomers with radical initiator were studied and the initial rate of polymerization of fumarate was about thirty times as large as that of maleate.
Residual double bond in polymers and infrared spectra of polymers indicated theformation of 5-membered lactone ring in both polymers and another 4-membered lactone ringin polymaleate. The difference of percent cyclization between two polymers was discussed.

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Viscosities of concentrated solutions of acrylonitrile-methyl acrylate copolymers (methyl acrylate contents in copolymers were 3-5%) in dimethyl sulfoxide were measuredby a rotational viscometer (so-called Brookfield-type viscometer). The viscosities of the solutions (below 200 poise) negligibly increase with standing time at room temperature.
The logarithm of the viscosity is proportional to 5 log C (or C), to 3.4 log M_ω and to 1/T, where C is the concentration of the polymer, M_ω the weight average molecular weight of the polymer and T the absolute temperature. The activation energy of viscous flow is 4.7-5.3cal/mole°C which is larger than that for the solutions in dimethyl formamide. Viscosities of the concentrated solutions are smaller in dimethyl formamide than those in dimethyl sulfoxide under the same conditions.

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The apparent viscosities η_a of concentrated cyclohexanone solutions of polyvinyl chloride with various molecular weights have been measured by Maron-Krieger-Sisko type viscometer at the rate of shear of 10^-1-10⁴ sec^-1 and the temperature, ranging from 21 to 60°C.
1) The data on the temperature dependence of apparent viscosity are fully explained by the reduced variables.
2) The relationships between the zero shear viscosities and the concentrations are given by two straight lines on a log-log scale.The concentration corresponding to the point to intersection is the so-called critical concentration (C_c).The slopes of the two lines are approximately 5.2 and 3.3 in the ranges higher and lower than C_c.respectively at 30°C.
3) C_c√Z (ρ: density of the solution, Z: chain length) is independent of the chain length at 30°C. This is not in agreement with Bueche's theory.
4) When the concentration was lower than C_c, a reduction mothod for the viscosity-concentration relationships proposed by Ferry and DeWitt was found to be inapplicable to our polyvinyl chloride solutions. Above C_c this method is applicable to the present result after a considerable modification is made.

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The osmotic pressures and the viscosities were measured for a fractionated polydimethylsiloxane (M=107, 000) in various solvents over wide temperature ranges, and the second virial coefficients and the intrinsic viscosities have been determined.The results obtained are summerized as follows. 1) The magnitude and temperature coefficient of the second virial coefficient are related to those of the intrinsic viscosity. 2) The entropy of dilution varies with the geometrical character of the solvent molecule. 3) The heat of dilution is mainly affected by the substituents of the polymer chain and the solvent molecule. 4) as a measure of extension of polydimethylsiloxane in θ-solvent is 1.56. -γ₀² is mean square end-to-end distance, in the unperturbed state, and -γ₀f is that calculated assuming free rotation of the successive bonds in the polymer chain.

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Thermal conductivity of polymethyl methacrylate and crosslinked polyester resin was me-asured in the temperature range from 20° to 120°C.The thermal resistivity of polymethyl methacrylate decreases linearly with the decrease of the reciprocal of absolute temperature as has been previously observed for same polymeric substances.This slope changes discontinuously at near the glass transition temperature.Above this temperature the resistivity decreases more steeply with the reciprocal of absolute temperature.The conductivity of polymethyl methacrylate was considerably lower than that of polyethylene.This may be due to the differences in both the symmetry of structure of molecular and the regularity of molecular configuration in the solid aggregate.These geometrical factors come from the effect of the side groups.
The results for polyester suggest that the temperature dependence is relatively small in the whole range of temperature of the present experiment.However, polyester having lower conductivity shows greater temperature dependence.These behaviors were discussed in terms of the difference in the degree of cross-linking of the samples.

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Thermal conductivity of nylon 6 (annealed) was measured in the temperature range from 20° to 100°C.The results seems to conform to a straight line of small negative slope, which was similar to that previously observed for low pressure polyethylene.The main purpose of the present study is to interpret this negative temperature dependence.
The partially crystalline polymer can be regarded as a binary system of amorphous and crystalline regions by neglecting the regions connecting them.If heat is transported through the crystalline region by the similar mechanism as in the case of dielectric crystals, the thermal conductivity will have a negative temperature dependence in the above temperature range. This unusual behaviour is explained for polyethylene by the assumption which is developed for binary solid mixture by the analogy of the electric conductivity and is available.

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The mastication of Styrene-Butadiene Rubber 1500 were carried out by an open mill under four conditions. Two of the four samples were treated for 10 and 30 minutes at 15°C, respectively, and the other two were treated for 17 and 35 minutes at 50°C respectively. These four samples and the unmasticated sample were fractionated by a factional precipitation method using benzene as solvent and methanol as precipitant.
The intrinsic viscosities and the osmotic pressures of unmasticated fractions were measured in toluene, and for the masticated fractions only the intrinsic viscosities were measured. The relationship between the number average molecular weight and the intrinsic viscosity was determined for the unmasticated sample of Styrene-Butadiene Rubber 1500, and the molecular weight of the masticated samples were calculated by this relationship.
It was found that the width of the molecular weight distribution curve decreased with increasing the treating time and with decreasing the temperature of mestication. This width was much more influence by the mastication temperature than by in terms of an treating time. The effect of mastication was discussed by the appropriate parameter which is related to the average width of the distribution curve. The relationship between the number of the fractions and the molecular wight distribution were discussed.

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We obtained the electron micrographs which seem to illustrate the process by which folded molecules in a polyethylene single crystal are stretched into a drawn fiber. When a single crystal is torn into two pieces, small fragments of the crystal are at first dragged out from the torn edges of both pieces and next the molecules are drawn out from the fragments and gathered into a fiber of about 30-50Å in diameter. Many small fragments in unstretched state can be seen in these fibers. This suggests that there may remain a considerable fraction of original fold molecules in the usual stretched fiber.

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The system consisting of dimethyl sulfoxide and toluene was found to be effective for fractionation of polyacrylonitrile. Discussion was made on the effect of the volume fraction of polymer in the gel phase upon the efficiency of fractionation, on the basis of data on the fractionation for this system and a few other systems such as dimethyl formamide-heptane, dimethyl formamide-heptane-ether, hydrooxy acetonitrile-benzene-ethanol and 60% nitric acidbutanol. The volume fraction of polymer in the gel phase, ν₂′ plays a very important role in the efficiency of fractionation, which is accordingly determined by the initial concentration of the polymer and the fractionation temperature. For a constant concentration of the total polymer, any appreciable differences in ν₂′ and the efficiency of fractionation were not observed among the solvent precipitant systems.
From the measurements of light scattering, diffusion constant and intrinsic viscosity the molecular homogeneity of the fractions was discussed and it was found very good.

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Several problems were discussed on the fractionation of polyacrylonitrile using the nitric acid-butyl alcohol system and the following results were obtained:
1) It was concluded from the infrared absorption spectra measurements and the analysis of the nitrogen content, the hydrolysis of nitrile groups did not occur during the fractionation using 60% nitric acid at 5°C.
2) Molecular weights of the fractions were constant during the treatment with nitric acid or mixture of nitric acid and butanol.
3) Efficiency of fractionation was improved by increasing the nitric acid content in the mixture, but the reaction between nitric acid and butanol interfere with the fractionation.
4) In the case of the nitric acid-butanol system, anomaly of the shape of the molecular weight distribution curves graduly disappears as the average molecular weight of the sample decreases.

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Several problems were discussed on fractionation of polyacrylonitrile through use of dimethylsulfoxide-toluene and dimethyl formamide-heptane systems. The following facts were revealed:
1) Addition of acids to the fractionation system prevents the discolouration of polyacrylonitrile in the fractionation process. In the case of the fractionation at high temperature, however, caution must be taken for the degradation of the polymer chains induced by the action of the acids.
2) The efficiency of fractionation is lowered by addition of acids in to the fractionation system.
3) Such systems as dimethyl formamide-toluene cannot be used for fractionation of polyacrylonitrile, in which the concentrated phase becomes colloidal.
4) The efficiency of fractionation is depressed by adhesion of the gel particles on the glass wall.
5) The efficiency of fractionation is lowered by the stirring of the solution for an unnecessary long time in the process of the separation of the gel phase.

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Careful measurements of intrinsic viscosity and light scattering were made for fractions of polyacrylonitrile prepared by repeating refractionation using dimethyl sulfoxide as a solvent and toluene as a nonsolvent. The relationships among second virial coefficient, end-to-end distance of a polymer chain, intrinsic viscosity and molecular weight were obtained over the molecular weight range from 91, 000 to 762, 000. For dimethyl formamide solution of the fractions of polymers prepared by the redox polymerization method with ammonium persulfate-sodium bisulfite as the catalysts. The above relationships are in good agreement with our previous results obtained from the measurements of diffusion constant and intrinsic viscosity.
It was thus confirmed that diffusion-viscosity method was a very reliable method for determining the molecular weight. Another investigation was made on fractions of polyacrylonitrile obtained by suspension polymerization method with α-α′-azo-bis-isobutyronitrile as the catalyst in aqueous phase.
It was found that molecular weights of these fractions were higher than those of the polymers of the same molecular weight obtained by the redox polymerization. This is in good agreement with Cleland-Stockmayer's and Onyon's results for polyacrylonitrile obtained through use of organic catalysts. These results indicates that catalysts used in polymerization have an important effect on the viscosity behavior of polymer solution.

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Intrinsic viscosities of polyacrylonitrile fractions have been determined, in various solvents over a wide temperature range. The solvents used were dimethyl formamide, dimethyl acetamide, ethylene carbonate, hydroxyacetonitrile, γ-butyrolactone and 60% nitric acid. The results were analysed in terms of Fory-theory which relate the intrinsic viscosity to polymer chain structure and to thermodynamic interaction between polymer and solvent.[η] changes with temperature through the coefficients Kand α³ in his equation.
For polyacrylonitrile solutions, a increases with increasing temperature. On the other hand, the parameter K decreases more rapidly with temperature in this case than in the case of nonpolar polymer-nonpolar solvent systems. Consequently, the intrinsic viscosity decreases with temperature. Entropy of dilution parameter, ψ¹, and heat of dilution parameter, K¹, were calculated from intrinsic viscosities and their temperature coefficients. It was found that all solvents used were thermally poor and the solubility of polyacrylonitrile was well explained by the large contribution of entropy.

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