Ultrasonic velocity and attenuation have been measured on three kind of silicone rubbers. Measurements are made at frequencies of 0.71, 2.88, and8.64M_c/s and in the range of temperature from-60°C to+50°C.Above -30°C, all the samples show rubberlike high elasticity and sound velocities in them are almost the same as the velocity in silicone oil. Below-40°C, two of the samples lose their high elasticity as a result of crystallization.The other is found to keep its high elasticity to lower temperature beyond the range measured.

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The electrophoretic mobility of polyvinyl alcohol was measured with the Tiselius'apparatus. It was found, that polyvinyl alcohol molecules were negatively charged.The mobility depends on the concentration of the polyelectolyte, but is almost independent from the polymerization degree of the polymer.From the theory of the polymerization and the experimental determination of Yoshizaki the highest possible carboxyl content of polyvinyl alcohol is one or two carboxyl groups per molecule, but the experimentally found number of charge is much greater than this value.

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To investigate the behavior of plasticizers in polyvinyl chloride compounds, the diffusion coefficients of plasticizers in the compounds were measured from the migration rates of plasticizers at the contact surface of two piled sheets, each having different plasticizer concentration. By this method, the diffusion occurs at small concentration differences, and there needs no special apparatus or extracting materials, and many measurements can be taken at the same time. For the following plasticizers, TCP, DOP, DOA and BBP, the diffusion coefficients were measured over the range of 20°-140°C, and 20-60 percent plasticizer.

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Authors have reported in previous papers that the size and shape of PVC chain were changed by mastication. In this paper effects of the addition compounds, such as the radical accepter and generater, on the recombination of degraded chains are described. It is a mechanism for recombination of PVC in mastication that double bonds formed along the chain by thermal decomposition of PVC are activated by chain radicals, which are formed with mechanical rupture of the chain. During the formation of a small amount of double bond, the chain radicals may be stabilized by disproportionation or oxygen.

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The equilibrium melting temperature of crystalline polyethylene terephthalate is depressed by copolymerized ethylene isophthalate units and the following Flory relationship between crystallite melting point and mole fraction of the units forming the crystallites shows fair agreement with the results obtained.(1Tm)-(1/T^m) =-(R/h_n)·lnXFrom this, the latent heat of fusion per ethylene terephthalate unit is calculated to be about 2600 calories.Specific volume-temperature measurements carried out dilatometrically on amorphous polyethylene terephthalate and its copolymers over a temperature range of 20° to 70°, indicate two second-order transitions in each case.The change in the expansion coefficient at the lower transition (at 34°-40°C) is unusually small, but unmistakable.The upper transition point is lowered linearly, at least up to 20% in mole fraction, by copolymerized ethylene isophthalate unit.If such copolymers are melt-spun, oriented by drawing to produce fibers and dyed with a non-ionic dye (e.g.with an aqueous solution of p-aminoazobenzene as a model of disperse dye), the increase in the equilibrium dye uptake is found to be linearly related to the percentage amount of ethylene isophthalate in the copolymer, demonstrating the increased dye receptivity due to the lowering of the degree of orientation and crystallinity.

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A study has been made of the effect of dimethylaniline on the polymerization of styrene, methyl methacrylate, butyl acrylate, vinyl chloride, and acrylonitrile initiated by 2, 2′-azobisisobutyronitrile at 50°C.It was found that the rate of polymerization decreased with addition of dimethylaniline, but the rate of decomposition of 2, 2′-azobisisobutyronitrile remained constant.The chain transfer constants for the polymerization of these monomers were determined according to Mayo's equation.It was observed that the values of the chain transfer constant for dimethylaniline were proprotional to those of the retardation by the latter.Fromthese results, it is assumed that the decrease in rate of polymerization by addition of dimethylaniline is due to the chain transfer reaction.

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