Tensile tests were carried out of bi-axially stretched rigid PVC sheets. Test pieces were prepared from a sheet material for thermoforming use by the technique and the apparatus for thermoforming. The stretch ratios λ and μ along their two main axes were 0.5-6. Effect of stretch ratios was studied by a graphic analysis, and the following results were obtained. i) The yield stress values are almost independentof the stretch ratios both for notched or unnotched pieces. ii) The breakage and yield energy of notched pieces comparatively depend on the stretch ratios. iii) The product and the ratio of a set of these longitudinal and transverse characteristic values have correlations with the product λμ and the ratio μ/λ of the strech ratios respectively. These correlations are easily understood from the plot of the data in logarithmic scale. iv) In the case of uni-axially stretching the reinforcement is induced only along the stretch axis. Along the direction perpendicular to this axis rather significant weakening occurs. The bi-axial reinforcement seems to be due to the superposition of such uni-axial effects, and occurs only within a certain limited range of stretch ratios.

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The Doolitte equation for liquid viscosity can be reduced to an Andrade type equation when the contraction function C (T) =0, whereas it becomes non-Andrade viscosity (glass viscosity) equation when C (T)>0. The function C (T) has a maximum value near the glass transition temperature T_g, and decreases rapidly to zero at its both sides. At the temperature region near T_g, the equation can be led by various approximations to Fox-Flory, WLF and Tobolsky- Catsiff types of viscosity equations. The two parameters in each equations are related each other and the Fox-Flory, WLF and Tobolsky-Catsiff equations are applicable in temperature ranges near, above and below T_g, respectively.

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[in Japanese]

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Polyethylene and polystyrene were mechanically mixed and the solution viscosity of the mixture was measured. Grafts of styrene to polyethylene were prepared in a heterogeneous phase by r-ray irradiation and the solution viscosities of the grafts were compared with those of the polyethylene-polystyrene mixture. The solution viscosities of the mixture were less than those calculated for the ideal mixture of homopolymers of the same molecular weight: there was siginificant decrease for the mixture containing smaller quantity of polystyrene. On the other hand, the solution viscosity of the mixture of polyethylenes of the different molecular weights was the same as that calculated for the ideal mixture and it was found that the additivity of the solution viscosities was confirmed for the mixture of the same homopolymers. The solution viscosity of the graft was higher than that of the mixture and the limiting viscosity number of the graft increased with the quantity of the graft per molecule. The structure of the graft polymer was discussed from the experimental results described above.

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A quantitative method for the analysis of temperature dispersion curves of dynamic modulus is proposed.
Tobolsky's empirical equation for the time characteristics of relaxation modulus was applied to the real part of dynamic modulus and a corresponding equation for mechanical loss tan δ was deduced. These equations were then transcribed into the form of temperature characteristics.
It is shown that the temperature and the frequency dependence of the viscoelasticity can be evaluated separately from a temperature dispersion curve at a single frequency.

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At the reaction of Epon 828 with n-butylamine and ethylenediamine in mixed benzeneethylalcohol solution the increase of viscosity with reaction time was well represented by equation ηγ=1+αt-At² (n-butylamine) and ηγ= 1/(1-αt+Bt²)(ethylenediamine), where ηγ is (solution viscosity at time t)/(solution viscosity at time 0):α, A, , β and B are constants. a and β was proportioned to the product of the initial concentration of reagents (amine and epoxide), and increased with the temperature and the content of ethylalcohol in solvent. The apparent activation energy of reaction calulated from the temperature dependence of a and β were 11.6-11.8 kcal/mol and 13.2 kcal/mol, respectively.
From the relationship between β and the extent of reactionit was found that course of the reaction could be pursued by viscosity measurement.

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Copolymerization reactions of mixed anhydrides of a, co-dicarboxythioethers and aromatic dibasic acid have been investigated. Four groups of new aromatic and aliphatic a, w-dicarboxythioethers of the following general structures have been synthesized and the optimum reaction condition for the preparation has been determined.
Copolymerization reactions of various a, w-carboxythioethers and terephthalic acid were carried out with acetic anhydride at 200-300°C under vacuum in N2 atmosphere. The mixed polyanhydrides of random structure were thus synthesized and the diagram of composition versus crystalline melting temperature was obtained. The mole fractions of the two acid components were found to be 40-60 mol% of terephthalic acid and 40 60 mol% of a, wdicarboxythioethers for copolymers melting at 200-300°C. The crystalline melting temperature of a random copolymer was confirmed to depend on its composition in accordance with the following Flory's relationship.
From Flory's equation, the value of heat of fusion per repeating unit of crystalline, hμ=1400-1970 cal/repeating unit and entropy of fusion, Sμ=3.4-4.8 cal/repeating unit/deg was obtained. The molecular structure of new polythioetherpolyanhydrides was presumed on the basis of infrared spectra and X-ray studies of these polymers.

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Isobutyl vinyl ether and t-butyl vinyl ether were polymerized by BF8.0 (C2H5) 2 in various solvents. The limiting viscosity numbers of the polymers decreased with increasing the dielectric constant of the solvents used. This result was the same as that obtained in the polymerization of methyl vinyl ether. Monomer transfer constant ratios and spontaneous termination constant ratios were calculated and compared with those of methyl vinyl ether reported previously. From the experimental results it was found that the mechanisms of the monomer transfer and termination reactions in the polymerization of the butyl vinyl ethers were identical with those in the polymerization of methyl vinyl ether.
In the polymerization of the butyl vinyl ethers, however, both the transfer and termination reactions were mainly influenced by the dielectric constant of solvent rather than the polymerization temperature. This tendency was opposite to that of methyl vinyl ether. The activation energies of both reactions were nearly equal to zero in the solvent of higher dielectric constant.
These results were explained by the differences in inductive and steric effects among the alkyl groups, and those in the stability of the alkyl cations.

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