Thermal decomposion of polyethylene films prepared by Ziegler process and with no stablizer were carried out. The weights decreased of the films was observed at 170°C, but the weights increased for several hours and then began to decrease at 150°C. In case of the films containing stabilizer the weight changes were observed after the induction periods corresponded to antioxidants used. By measurements of induction period of various antioxidants, the kinds of effective antioxidants were known.

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A stereoregulating effect of monomer structure on polymerization of vinyl ester was observed in the case of polymerization of vinyl formate. Polyvinyl alcohol derived from polyvinyl formate was found to have much more less amount of 1, 2 glycol bond and higher water resistivity than those of the polymer derived from polyvinyl acetate.
It was found from the experimental results that the amount of 1, 2 glycol bond in polyvinylalcohol derived from polyvinyl formate varied with the dielectric properties of the polymeri zation media, and this conclusion was in contract to those obtained from polyvinyl acetate, and the minimum value of 1, 2 glycol content in polymer was observed in the case of bulk polymerization and the high value of 1, 2 glycol content in the case of polymerization in high dielectric media. It was concluded from these results that the effect of the association of formyl group on the stereoregulating polymerization as well as the steric and electrostatic effects was important for the polymerization of vinyl formate.

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The limiting viscosity number-molecular weight relations in various solvents for polyvinyl formate (PVF) derived from polyvinyl alcohol (PVA) are determined from the measurements of the viscosity and the estimation of the molecular weights of PVF from those of original PVA, and the results obtained are as follows:
The following relations of the limiting viscosity number between PVA and PVF, or polyvinyl acetate (PVAc) and PVF are derived from the equations described above and equations already given by other authors.
It is found that PVF obtained at high temperature shows a considerable degradation through the course of hydrolysis, and a degree of polymerization of PVF is in agreement with that of PVA within experimental error, when the polymerization is carried out at a temperature lower than-30°C.
The high values of the Huggins constants for PVF are shown to be generally due to the branching of polymer molecule.

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The changes of the physical properties of polyvinyl formate with polymerization temperatures were studied from the measurements of density, glass temperature, solubility, rate of gelation, X-ray and infra-red spectrum. The specimen polymerized at low temperature showed a sharp line on the X-ray diagram and the drawn sample gave a fiber diagram, and the identity period of 5 Å obtained was shown to be related to a syndiotactic structure of polymer. The infra-red absorption bands of 1420, 1272, 1026 and 924 cm^-1 obtained from the measurements of spectrum could be related to the crystallization of the polymer.
It was concluded from the results obtained for polyvinyl formate that a decrease of polymerization temperature was generally related to an increase of syndiotacticity of polymer.

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Kinetical considerations concerning the polymerization of vinyl acetate in methanol initiated by a-a′-azo-bisisobutyronitrile (AZN) gave following conclusions. 1. The rate constant of the decomposition of AZN and the concentration of impurity in monomer are calculated from the relationship among polymerization temperature, the concentration of initiator and inhibition period, under the assumption that the inhibition period is the time during which the impurity in the monomer is exhausted by the radical formed by the decomposition of initiator. The calculated values seem to be reasonable. 2. The values of k_t/k_p² and its apparent activation energy (E_t-2E_p) are calculated from degree of polymerization and the initial rate of polymerization, and the values obtained are in agreement with the literature values in the bulk polymerization. 3. The chain transfer constant of methanol is also calculated to be 5.5 (70°C) and 4.3 (60°C), its activation energy (E_s-E_p) being 5.5 kcal/mol.

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The aqueous solution of the polyvinyl alcohol (PVA-I) derived by alkaline methanolysis of polyvinyl acetate polymerized in the presence of aldehyde showed a reversible color change with the change of pH, yellow brown in alkaline and colorless in acidic state.
However, the polyvinyl alcohol (PVA-II) derived from polyvinyl acetate polymerized in the presence of acetone was colorless, even in alkaline state.
Spectroscopic study was carried out about PVA-I, PVA-II, and 2, 4-hexadienal. From the resemblance of spectroscopic behavior between PVP-I and 2, 4-hexadienal, it was considered that the course of color change of PVA-I was due to the tautomeric keto-enol isomerization of terminal carbonyl group.

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In the course of synthetic studies on various aromatic polyanhydrides new aromatic polyanhydridesof 1, 4-bis (β-carboxyethyl)-benzene containing two adjacent methylene groups between aromatic nucleus and carboxyl function in the main chain has been synthesized.
β-chloropropionitrile was prepared from readily available acrylonitrile and hydrogen chloride as a starting material, followed by Friedel-Crafts reaction of β-chloropropionitrile and benzene in the presence of anhydrous aluminum chloride to afford 1, 4-bis (β-cyanoethyl)-benzene. Thus purified 1, 4-bis (β-carboxyethyl)-benzene was synthesized by hydrolysis of 1, 4-bis (β-cyanoethyl)-benzene in 50% H₂SO₄ and the optimum reaction condition was determined.
Polycondensation of purified 1, 4-bis (β-carboxyethyl)-benzene in the presence of acetic anhydrideat 150-180°C under vacuum in N₂ atmosphereafforded new crystalline polyanhydride of melting point at and.
With an attempt to elucidate the relationship between chemical structure and physical properties of polyanhydrides, infrared absorption spectra and X-ray diffraction pattern were studied and the influence of molecular structure on the physical properties was discussed.

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Copolymerization reactions of mixed anhydrides of methylene-bis-(p-carboxybenzoyl)-amide and aliphatic dibasic acids have been investigated. As aliphatic dibasic acids, either adipic acid or sebacic acid were chosen as one component and methylene-bis-(p-carboxybenzoyl)-amide was used as another component which was prepared by acid catalized condensation of p-cyanobenzoic acid and formaldehyde and the diagram of composition versus melting point of copolymers was obtained. The melting points of crystalline polyamidepolyanhydrides decrease with diminishing mole fractions of amide-dibasic acid.
It was confirmed from the relationship between copolymer composition and crystalline melting temperature of a random copolymer that the following Flory's equation hold in the mixed polyamidepolyanhydrides.
(I/T_m)-(I/T_m⁰)=-(R/h_u)InX_A
From Flory's equation, the value of heat of fusion per repeating unit of crystallite, h_u=2, 600-2, 620 cal./repeating unit, and entropy of fusion, S_u=8.06-8.08 cal./repeating unit/deg. were obtained. Furthermore, the molecular structure of new crystalline polyamidepolyanhydride was presumed on the basis of infrared spectra and X-ray diffraction pattern of the polymer.

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Acrylic acid was polymerized in aqueous solution of different pH using (NH₄) ₂S₂O₈ as an initiator at 50°C. The obtained polyacrylic acids differed considerably from each other in the potentiometric titration behaviors and the solubilities. These results would mainly be due to difference of the steric configurations of these polymers. The polyacrylic acids obtained by polymerization in aqueous solutions with pH 7 and low monomer concentrations, seem to be more syndiotactic.

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In the case of producing the spinning solution which are prepared by solution polymerization of acrylonitrile in zinc chloride aqueous solution, it is necessary for the solution to have an excellent transparency, in order to spinning fiber with high whiteness.
It has been known that, for producing its transparency, the following conditions are required: The polymerization must be done (1) at the lower temperature, (2) at the state of the lower pH, namely adding acids to the solution, and (3) in the existence of smaller amounts of the catalyser (or sensitizer).
It was found that, as an excellent sensitizer, α, α′-azobisisobutylonitrile, benzoin, uranyl nitrate, hydrogen peroxide and ammonium persulfate, etc. were effective, on the other hand benzil, benzophenone, stannous chloride and cerium nitrate, etc. were not so effective.
Rate of polymerization depends upon the concentration of monomer and sensitizer as following;
sensitizer rate of polymerization
uranyl nitrate
αα′-azobisisobutylonitrile
benzoin
ammonium persulphate
hydrogen peroxide
: where C is the concentration of sensitizer.
α, α′, α″, α′′′ and β represent constants.

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Photo-polymerization of acrylonitrile in aqueous zinc chloride solution has been studied and the following results were obtained.
1) The relationship between the photo-rate (RP) and the light intensity (I) were observed as
Rp ∝ I^0.5 for αα′-azobisisobutylonitrile (ABIN)
Rp ∝ I^0.5 for ammonium persulfate (APS)
and Rp ∝ I^0.7 for hydrogen peroxide (HPO)
2) The ratio of absorption coefficient of ABIN and benzoin (BZI) to that of HPO were estimated as 7.82 and 12.5 respectively. In our experimental conditions, the observed photo-rate was expressed as
log Rp = A′-α· c · n · d ·
where α is the absorption coefficient, c the sensitizer concentration, d the length of light path and n the intensity exponent of photo-rate. A′ represents a constant (at a given monomer concentration), so that when the magnitude of (α· c · n) is considerably smaller than that of A′, the lowering of photo-rate along the light path will be small even at a distance far from the incident surface of light. The observed values of (α· c · n) are 0.77 for HPO, 2.25 for ABIN and 3.78 for BZI. Photo-polymerization with HPO was found to show the best homogeneity in both the photo-rate and the molecular weight of polyacrylonitrile produced along the light path.
3) Photo-rate depended on the concentration of zinc chloride in the reaction medium and their relationship was shown by
Rp=k [AN](α′+ [AFS] ^0.5)[ZnCl₂] ^2.50 for APS
and Rp=k [AN](β′+[HPO] ^0.5)[ZnCl₂] ^2.30 for HPO
where α′ and β′ represent constants.
Also, reciprocal of the molecular weight of the polymer produced was found to de proportional to the square of zinc chloride concentration.

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The model compounds for polyacrylonitrile, CH₃ [(CN) CH₂] _1-4H, were employed to investigate the mechanism of coloration, which occured when the polyacrylonitrile was treated with alkaline reagents.
The investigation began with observing the change of ultra-violet absorption spectra which occured when the model compounds were treated with KOH in dimethylformamide. Then it was detected that the cyclic structures were formed from CH₃ [CH (CN) CH₂] _2-4H by the action of KOH, and at the same time the colorations were observed in the case of CH₃ [CH (CN) CH₂] _3-4H.
Therefore, to detect the cause of coloration, the derivatives of glutaroimide or glutaroimidine were synthesized, and treated with KOH to test the coloration, and submitted to the measurement of ultra-violet absorption spectra. After that, it was detected that the glutaroimidering was not related to the structure of colored polyacrylonitrile, but octahydro-2, 7-diirnino-3, 6-dimethy-1, 8-naphthylidine, which obtained from CH₃ [CH (CN) CH₂] ₃H by treatment with NaNH₂ in the case of synthesis of glutaroimidine derivatives, was a unit model compound for colored polyacrylonitrile. Thus the usual hypothesis for the coloration of polyacrylonitrile, which was related to the formation of naphthylidine like structure, was proved substantially.

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The change of ultra-violet absorption spectra of model compounds in ethanolic KOH solution were observed to compare with the results obtained in dimethylformamide (DMF). In this case the formation of cyclic structure was also detected as in DMF, but the velocity of ring formation was far lower than that in DMF. Moreover in the case of CH₃ [CH (CN) CH₂] _3-4H the coloration did not occur, while polyacrylonitrile was colored with KOH in ethanol. Therefore it is evident that the colored cyclic structure should be formed with KOH even in ethanol when many nitrile groups exist along the molecular chain, though CH₃ [CH (CN) CH₂] _3-4H could not be colored with KOH in ethanol.
Especially, polyacrylonitrile copolymerized with acryloamide was colored more rapidly than straight polyacrylonitrile with KOH in ethanol. So the difference of velocity of ring of and formation between structures of and was semiquantitatively investigated with model compounds. Then it was detected that the velocity of later structure was ca. 400 times as large as that of the former structure.
Thus, it may be considered that the amide group being in polyacrylonitrile chain reacts rapidly with KOH to form colored cyclic structure.

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Linear and branched (numbers of branched units per molecule were about 8) polyvinyl alcohol fractions of the same degree of polymerization (7, 000) were partially acetalized with glyoxylic acid or o-phthalaldehydic acid. The potentiometric titration behaviors of linear polymers were almost the same as those of corresponding branched polymers with the same amount of COOH groups. On the other hand, the viscosity of dilute aqueous solutions of linear polymers were considerably higher than those for branched polymers. PVA samples partially acetalized with o-phthalaldehydic acid showed abnormal behaviors of the viscosity. Some discussions were given for these results.

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