The steric structure of high polymers was studied theoreticaly, assuming that the rate of monomer addition depended on the steric arrangement of the end of the growing chain. Equation (2) was deduced for the fraction (f_iso) of isotactic structure in the polymer, considering he four propagation reactions with different rate constants (equation 1).
iso+M→iso (k₁) iso+M→syn (k₂) syn+M→iso (k₃) syn+M→syn (k₄)(1)
f_iso= (1+r₁)/(2+r₁+r₂): r₁=k₁/k₂, r₂=k₄/k₃ (2)
Then, following equations were deduced for the fraction (F_n) of isotactic structure which contained n sequence of the isotactic bond and for the fraction (G_m) of isotactic structure which contained more than m sequence of the isotactic bond.
F_n=f_iso/(1+r₁) ²·n·(r₁/1+r₁) ^n-1 (3)
G_m=f_iso (1+m-1/1+r₁)(r₁/1+r₁) ^m-1 (4)
Under such conditions, F_n and G_m of high polymers which have the same value of f_iso may differ respectively. Some discussions were given for the method of the determination of r₁ and r₂ values.

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The branched polysiloxane polymers which have controled amount of trifunctional group have been prepared from hexamethyldisiloxane, octamethylcyclotetrasiloxane and methyltrichlorosilane. The dilute solution viscosity of polymers were studied as the function of the degree of branching.The ratio of observed [η] branched of branched polymer to the calculated [η] linear are compared and discussed with the theoretical results of Zimm-Stockmayer.

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The branched polysiloxane polymers in which the trifunctional branch point labeled with phenyl group, were prepared from hexamethyldisiloxane, octamethylcyclotetrasiloxane and phenyltrichlorosilane. The polymers were fractionated from MEK solution into six parts using methanol as precipitating agent.The number of branching point in each fraction was measured from the absorbance in ultraviolet spectrum. It was found that the number of branch points per unit volume or weight of polymer are about same in all fractions and distribution of branching points in polymer may be independent to the degree of polymerization.

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Effects of specimen volume has been examined on tensile strength at each strain rate. The tensile strength S can be represented as following: S=const.-α-·log V at the low strain rate, log S=const.-β·log V at the high strain rate, where V is the volume of specimen, α and, β are parameters.Measurements of tensile properties (tensile strength, ultimate strain and energy of rupture) were carried out at rate of extension from 3×10^-3 to 4×10² centimeters per second.The tensile strength increased about 5.5% for every tenfold increase in the low rate of extension and about 12% for every tenfold increase in the high rate of extension. The ultimate strains were independent on the rate of extension in the low rate of extension and decreased with increase of rate of extension over 0.8 meter per second.

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The moisture effects on stress strain curves (ranging from 0 to 98% RH) has been examined at each extension rate: 2cm/min and 4 m/sec.Water acts as a powerful plasticizer, and tends to reduce ultimate strength and yield stress, but to increase ultimate elongation and toughness.Moisture effects are more sensitive at high rate of extension. Ultimate strength and yield stress decrease with increase of temperatures ranging from 20°C to 160°C. Ultimate elongation and toughness increase with increase of temperatures and are remarkable over glass transition temperatures (from 100°C to 120°C).

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Specific volume and thermal expansibility of the binary systems, nitrocellulose (NC)-PMMA, -PVAc, -castor oil modified alkyd resin, -TCP, and -castor oil, were studied for solvent-cast films dried below 90°C. The relation of specific volume to composition is found to be almost linear for the first two systems composed of the polymers having the glass transition point higher than the measuring temperature.While, in the other cases, an abrupt increase of specific volume is observed by adding a small amount of liquid component to NC followed by a relatively slow increase with the content of the former, though a linear relation holds for the region rich in liquid component.From the volume-temperature relation of NC-PMMA and NC-PVAc systems, the secondary transition (β) specific to NC is found to reveal so long as the content of NC is higher than about 30%, although the primary transition point (α) increases regularly with the content of NC. In accordance with these results, a distinct shrinkage is observed at about 40° and 100°C for specimens rich in NC. Furthermore, such a thermal shrinkage of NC film is found to be facilitated by pretreating the specimen with swelling agent such as aqueous acetone or methanol.

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The temperature dependence of viscoelasticity of the same specimens as those employed in the previous paper were studied by the free torsional oscillation method in which the oscillation period was kept at 3 to 10 sec. In the cases of NC-PMMA and NC-PVAc systems, the temperature giving the maximum damping, the glass transition point, is found to vary with the composition according to Gordon and Taylor's equation, although the secondary transition presumably due to NC is revealed as a shoulder in the logarithmic decrement versus temperature curves. So far as viscoelastic behaviors concern, the effect of TCP or oil modified alkyd resin is substantially similar to that of PVAc.

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Polymers of vinyl chloride were prepared by a Redox system at 50 and -5°C. Two graft polymers were also obtained at these temperatures. The 2nd-order transition points and densities of these polymers were measured. By using LiA1H₄, these polymers were reduced to polyethylenes, of which the degree of crystallinity and the softening points were determined. From these results, it was obserbed that the polyvinyl chloride polymerized at lower temperature had less branches and more stereoregularity.

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An aqueous polymerization of acrylonitrile at 60°C was studied radiochemically using S⁸⁵-labeled potassium persulfate initiator. The number average molecular weight of polyacrylonitrile was estimated from the limiting viscosity number of N-, N-dimethylformamide solution at 25°C. The number of initiator fragments per polymer molecule was determined to be about one. It was also shown that the chain termination occurs dominantly by bimolecular reaction. These results indicate that the disproportionation is the dominant chainterminating process.

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We found that ai-bromacetophenon (I) was useful as a photosensitizer for the polymerization of vinyl acetate by ultraviolet light. The rate of photopolymerization, when I was present rate constant, in the reaction system, was high even at low temperatures. From the experimental result at 0°C, we obtained the following values; 3×10^-4 for monomer transfer constant, 4 for k₁/k_p², 6.47 kcal/mol (log R_p-1/T relationship) for apparent activation energy of photopolymerization, respectively, where R_p, k_p, k₁, and T are rate of photopolymerization, propagation rate constant, termination rate constant, and absolute temperature, respectively. We also observed the ultraviolet light absorption and decomposition of w-bromacetophenon.

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The change of polyamide by heating is measured in the temperature range of molding. Loss of weight by heating is measured against temperature and time by thermal balance. Relation between molecular weight and heating time is measured by heating polyamide in oil bath. From above experiments, it is found that several characteristic temperatures exist for the change of polyamide by heating, and molecular weight increases moderately in the temperature range of molding.

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This paper describes the reaction of polyphosphonitrile chloride and aliphatic alcohol, and the properties of the condensed alkyl polyphosphonitrilic acid esters.(1) Preparation of triphosphonitrile chloride: By the use of sym-tetrachloroethane as a solvent, triphosphonitrile chloride (PNC1₂) ₃ was prepared from phosphrous pentachloride and ammonium chloride for 20 hours at 120-130°C, mp 113-114°C.(2) Polymerization of triphosphonitrile chloride: Triphosphonitrite chloride was polymerized in a sealed glass tube for 3 hours at a temperature of 300°C, and polyphosphonitrile chloride (PNC1₂) _n was produced in the form of elastic rubberlike polymers.(3) Alkyl polyphosphonitrilic acid esters [PN (OR) ₂] _n were obtained by refluxing a mixture of (PNC1₂) _n and aliphatic alcohol such as ethyl, butyl, amyl, octyl, and lauryl, respectively in satisfactory yield.

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