The refractive index and density were measured to examine the density dependence of the molar refraction of the crystalline high polymers such as polyethyleneterephthalate, polyethylene, polyacrylonitrile, and a series of polyamides. From the experimental results it was found that the molar refraction was constant regardless of the degree of crystallinity and the crystalline structure. The observed values of these molar refractions agree, except polyethylene terephthalate, with values calculated from the sum of the atomic refractions of the atoms in the structural unit of the polymer chain. The larger observed value than the calculated one is presumed to be due to the exaltation caused by the conjugation between carbonyl group and benzene ring.

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The viscosities of polyethylene in tetrarin have been studied as a function of rate of shear. Standard samples used was supplied by Polyethylene Research Group in Japan. The intrinsic viscosity [η] at zero rate of shear was determined for each sample. The shearing rate dependence of [η] for these samples did not show much differences between the various types of polyethylenes. An unusual, nonlinear η_sp/C-C curves were observed for some samples of linear polyethylenes.

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The knowledge on the thermal efficiency and the apparent heat transfer coefficient at the barrel wall are important for designing the extruder. The investigation of these characteristics were carried out for low pressure polyethylene at the operating conditions of a polytropic extruder. The thermal efficiency increases with the diameter of the die nozzle and the revolutional speed of the screw and it seems to show a maximum at a higher revolutional speed. The smaller is the diameter of die nozzle, the lower the critical revolutional speed at which the screw input equals to the effective heat content. The local value of apparent heat transfer coefficient is greater in the lower temperature region. The mean value of apparent heat tranfer coefficient increases slightly as the diameter of die nozzle decreases and increases as the revolutional speed increases.

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Viscosities of spinnabilities were measured for six molten polyethylene samples in the molecular weight range, 3450-7200. A glass rod of 2 mm in radius was dipped into the molten polyethylene and drawn up at various velocities V (cm/sec). The length of the liquid thread l (cm) increased linearly with the immersed depth of the rod. Defining the length at zero immersed depth as l₀, l₀ increased with _V and decreased with rising temperature. Its dependency on temperature and molecular weight of the polymer could be attributed to the variation in bulk viscosity η(poise). It was shown that l₀ can be expressed by the following experimental formula

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In order to study the action of water in heat-setting of nylon 6 fibres, an infra-red-spectroscopic method was used for the investigation of exchange reaction between active hydrogen atom of acid amide group in nylon and deuterium oxide. It is assumed that the exchange reaction occurs only in the amorphous regions in the solid phase. Comparison was made between infrared spectra of nylon 6 films (N-H polymer) deuterated in the vapour phase at low and high temperatures with those of the polymer (N-D polymer) produced by polymerization of proviously deuterated ε-caprolactum, for which the whole hydrogen atoms are exchanged by deuterium. The changes in accessibility of both N-H and N-D polymers were measured from the spectra of the samples obtained by repeating the steam-setting alternately in D₂O and H₂O vapour at the same temperature. The results obtained shows that by the initial steam-setting in D₂O vapour, deuterium oxide molecules may penetrate into the ordered regions in the polymer films and break down partly intermolecular hydrogen bonds, followed by exchange reaction and recristallization. In subsequent steam-setting, however, such reaction no longer proceed.

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In heat setting of nylon 6 fiber, not only increase in the degree of crystallinity but also change of molecular spacing in the amorphous region may occur. Thus, changes of its viscoelastic and thermal behaviors are expected. Samples have been steam-set previously so that increase of crystallinity may not occur on subsequent treatments: steam or dry-heat setting and repeats of them, and gamma-irradiation. From the results, it has been considered that the intermolecular bonds were broken out by the steam-setting and reproduced by the dry heat setting reversibly. In the case of the gamma-irradiation, cross-linking is dominant in vacuum, while in air degradation predominates.

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Vinylidene chloride is copolymerized with some higher alkyl (n-octyl-n-octadecyl) vinyl ethers at 50°C in the presence of benzoyl peroxide as an initiator. Monomer reactivity ratios of vinylidene chloride (M₁) and each vinyl ether (M₂) are found as follows:
Vinyl octyl ether r₁=1.35± 0.15, r₂=0.0± 0.2;
Vinyl dodecyl ether r₁=1.30± 0.15, r₂=0.0± 0.2;
Vinyl octadecyl ether r₁=1.50± 0.15, r₂=0.0± 0.3.
The rate of copolymerization and reduced viscosity of copolymers decrease as the concentration of vinyl ether in a monomer mixture increases, when the copolymerization proceeds to a higher conversion, the content of vinyl ether in polymer molecules increases, followed by a decrease in the reduced viscosity. From the measurements on the tensile strength, elongation, specific gravity and solubility in organic solvents of copolymers, the interplastisizing effect of higher alkyl vinyl ethers is evoluated. The effects of alkyl chain length of vinyl ethers also studied.

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Some diesters and diurethanes were prepared by the reactions of N-carbethoxy-ε-aminocaproyl chloride, 5-carbethoxypentylisocyanate, or N-carbethoxy-6-aminohexylisocyanate with ethyl ε-aminocaproate, ethyl ε-oxycaproate, N-carbethoxyhexamethylenediamine, or N-carbethoxy-ε-aminohexanol. They contain one amide, urea, or urethane group in polymethylene linkage between two terminal ester or urethane groups. Syntheses of polymers having the regular structure of-A-A-B- type were attempted by the polycondensation reactions between the compounds described above and aliphatic diamines, diols, or dicarboxylic acids of 6 or 9 carbon atoms. Among them polyamide-ureas showed a good fiber-forming property.

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