The mechanical denaturation of PVA aqueous solutions by means of shearing force was studied. The experiment was done with a shaking method and the Hercules High Shear Viscometer. The PVA specimens used were those derived from three vinyl monomers.
The coagulations by shearing force were not observed in the case of the PVA derived from poly (vinyl acetate) (commercial PVA), but the fine fibrous coagulations were observed in the both cases of the PVA derived from poly (vinyl formate) which was polymerized at low temperatures (0--78°C) and of the PVA derived from poly (vinyl-trifluoroacetate). The mechanical denaturation of the latter PVA solutions was recognized.
The critical shear rate γ_c at which the coagulations were produced, was measured with the Hercules High Shear Viscometer. The smaller the γ_c was, the greater the concetration and the degree of polymerization of the PVA were.
It can be assumed that the syndiotactic parts beyond a certain length in a PVA molecule influence the production of the coagulations from the solution with shearing force.

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Effects of three remarkable factors liable to affect various properties of the leather sheet prepared synthetically from polyamide, i. e. the paste composition, polymerization degree of the polyamide used and solidifying conditions were studied. Their relations with the apparent density, tensile strength and elongation at the breaking point are specially investigated and led to the following conclusion:
1) The strength of a leather sheet increases according as the apparet density increases.
2) The apparent density of a leather sheet is largely affected by the working conditions under which methanol and CaCl₂ are removed off from the paste, while it is hardly affected by the paste composition.
3) The strength of a leather sheet increases to a certain extent by using a polyamide having a higher polymerization degree.
4) The ideal thickness obtainable of leather sheet in this system is assumed to be about 0.4mm, but the best possible strength obtainable is observed to be only 30-40% of that of the ideal sheet due to various defects discussed in the undergoing derscription.

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Small content of carbonyl group in thermally decomposed PVC was detemined by the ultraviolet absorptiometry. Carbonyl group in PVC was converted quantitatively to the Schiff's base by the condensation reaction with p-nitrophenylhydrazine or 2, 4-dinitrophenylhydrazine and its content was calculated by the experimental expression from the ultraviolet maximum absorbance of such the PVC derivative. For most reasonable absorptiometry the condensation product between PVC-halogen adduct and p-nitrophenylhydrazine was prefered to the other products. Further by consideration for the absorption characteristics of the Schiff's base of low molecular carbonyl compounds it was suggested that PVC decomposed in oxygen at ordinary pressure had principally enone structures with additionally saturated carbonyl and polyenone structures, and that at high pressure it had mainly the saturated carbonyl structures.

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By the method which we used in the preceding paper, we studied theoretically about the way how the formation of short chain branching structure will change by the addition of a small amount of α-olefin, for example propylene and butene-1, in the radical polymerization of ethylene. As the result, we obtained the following conclusions.
1) In the resulting short chain branching structures, the fraction of that including methyl branches, which results by the copolymerization of propylene, must be very much larger than the fraction of propylene in monomers.
2) When the propylene is added, it is natural that the number of methyl branches must increase, but also the number of branches except methyl branches must increase under the polymerization condition which the ordinary high pressure polyethylene is produced. (Number of ethyl branches/number of butyl branches) must also increase by the addition of propylene.
3) The result of 1) and 2) seems to be due to the following fact: When the propagating radical adds one propylene and then one ethylene, it changes to a radical of 3-methylhexyl type. According to the conclusion of the preceding papers, the radical of this type makes the branch formation very much easier than others. In the case of the butene-1 addition, one can apply the conclusion which we obtained in the case of the propylene addition without any substantial change.

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Highly isotactic and syndiotactic poly (vinyl alcohols) (PVAs) have been prepared by the cationic polymerization of vinyl trimethylsilyl ether under suitable conditions. Some properties of these PVAs were compared with those of the conventional stereoregular PVAs.
Highly isotactic PVA showed IR band at 1145 and 1160cm^-1, which the conventional isotactic did not show. In the syndiotactic PVA, the optical density ratio D₉₁₆/D₈₄₉ was found to be larger than unity. It was also found that the ratio decreased with increasing the annealing temperature.
Syndiotacticity lowered the solubility of PVA in water. Especially, a sample with 74% syndiotacticity was found to be insoluble in water at temperatures up to 150°C, and was soluble at 160°C. Highly isotactic polymer was found to be less soluble than the conventional isotactic one.
Melting points of PVA measured by the differential thermal analysis showed a minimum at around 20% syndiotacticity.
These unusual behaviors of the highly isotactic PVA in melting points, solubility and IR spectra seem to present a token of a new crystalline state in isotactic PVA.
The IR spectra of poly (vinyl acetates) derived from highly stereoregular PVAs were identical to those of commercial ones. The syndiotactic PVAc was not soluble in acetone and benzene, which are good solvents for the atactic and isotactic PVAc, but it was soluble in chloroform and chlorobenzene.

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The reaction rate for the acid-catalyzed hydrolysis of dimethylenetriurea (DMTU) was investigated in aqueous solution containing an excess of urea or not at room temperature and it was compared with that of methylenediurea (MDU) under the same conditions.
Thus, the following results were obtained.
1) Two different elementary reactions were respectively generated by the attack of a hydrogen ion on either of two imino group nitrogens ((1), (2) in (I)) in DMTU.
But it was deduced that there was not a great difference between the two rate constants.
2) The catalytic constant of hydrogen ion for the hydrolysis of DMTU at 28°C amounted to 1.07 l·mol^-1·min^-1and was in good agreement with that for the hydrolysis of MDU.

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Acetyl groups of acrylamide·N-acetyl-methylol acrylamide copolymers (AAm·Ac-M-AAm, Ac-M-AAm content 10-42mol%) were hydrolyzed with various polymeric sulfonic acids such as partially sulfonated polystyrene and polyvinyl sulfonic acid in water, and the rate constant of the hydrolysis (k_s) was compared with that of the hydrolysis carried out under the same condition with hydrochloric acid (k_HCl). The ratio of the rate constants r (=k_s/k_HCl) was generally larger than unity. It was dependent on acetyl content of the polymeric esters and structures of the polymeric sulfonic acids, and decreased by an addition of acetone. These behaviors are similar to those of hydrolysis of vinyl acetate-vinyl alcohol and vinyl acetate-vinyl pyrrolidone copolymers, but the r-value for AAm·Ac-M-AAm was generally smaller and less sensitive to the reaction conditions than that for the other copolymers. As a characteristic of the hydrolysis of AAm·Ac-M-AAm, it was found that polyvinyl sulfonic acid showed r-value larger than unity even in an acetone-water mixture (3: 7 by volume). Similar experiments were also carried out with methacrylamide·Nacetyl-methylol acrylamide copolymer. Some discussions were given for these results.

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