Dielectric properties of cellulose-triacetate, cellulose (2.4) acetate and cellulose (2.4) acetate plasticized with tributyl phosphate were measured over the wide frequency and temperature ranges, using a mutual inductance bridge and Q-meter.
For the unplasticized cellulose-triacetate, single broad loss curve was observed. The activation energy was estimated to be about 15 kcal/mol.
For the unplasticized cellulose (2.4) acetate, the absorption curve was characterized by the broad and asymmetrical shape. On the assumption of the overlapping of the two absorption curves, the acitavation energies were calculated as 15 kcal/mol and 13 kcal/mol for the absorptions at high and low temprature regions respectively.
These absorptions are reasonable considered to be related to the movement of the side chains, because the observed activation energies are too small for the segmental motion of the main chains.
For the sample containing 20% T. B. P., the observed absorption curve was similar to that of the unplasticized cellulose (2.4) acetate.
The sample containig 31% T. B. P., gave relatively simple absorption curve. The activation energy was about 14 kcal/ma The cause of this absorption is also assumed as the movement of the side chains.

View full abstract

Sorption isotherm measurements of iodine by nylon 6 were carried out in various solvents such as potassium iodide aqueous solution, acetone, benzene and carbon tetrachloride. In polar solvents such as potassium iodide aqueous solution or acetone, the amount of adsorbed iodine begins to increase sharply at a certain concentration and then arrives at saturation. The sorption isotherm curve is similar to Viewig' s curve in the case of alkali sorption for native cellulo-se. However, in nonpalar solvents such as benzene or carbon tetrachloride the amounts of adsorbed iodine was extremely smaller than those in polar solvents even at the same iodine concentration.
In the ultraviolet and visible region, various iodine stained nylon 6 films have strong absorption at the same wave length with that of iodine solutions dissolved in polar solvents, while the absorptions due to linear polyiodines are not observed. Optical dichroic ratio of iodine stained nylon 6 films shows that iodine is adsorbed in parallel with the polymer molecule andthe orientation of iodine is better in the crystalline region than in the amorphous one. These results indicate that long linear polyiodines are not formed and the nature of bond between the polymer and iodine resembles the coordinate bond of iodine to acetone or ether differently from the cases of iodine adsorption for amylose, cellulose and polyvinyl alcohole.
The results of the density measurements under various conditions suggest that the crystal structure of Nylon 6 was converted into another type of crystal structure by the iodine treatment.

View full abstract

Dynamic viscoelasticity of foam rubbers, its temperature dependence, and the effect of oxydative degradation were studied at about 100 cycles/sec. The apparent activation energy for viscous process was determind from the temperature dependence of dynamic viseosity. The observed value, 2-4 kcal/mol, is much smaller than that of rubber matrix itself, 15-20 kcal/mol.
The dynamic rigidity decreases and the viscosity increases at the first stage of oxydative degradation; and then both of them begin to increase at the last stage. The observed results are tentatively interpreted principally in terms of the colloidal higher-order structure of the porous rubber, rather than as the intrinsic properties of rubber matrix.

View full abstract

The apparent viscosity η of concentrated solutions of polyacrylonitrile in N, N-dimethyl formamide, having different molecular weights have been measured in the temperature range from 20 to 130°C by the falling sphere method.
1) Plots of log (falling time) as a function of 1/T (°K) ^-1 yield straight lines.
2) Log-log plots of the viscosities against the weight % concentrations of solutions follow lines of slops 5-6.
3) Log-log plots of the viscosities against the number average of the degrees of polymerization (Pn) at constant concentration and temperature follow lines of slope 3.5.
4) The apparent activation energy of flow varies with the concentration of the solution and can be extrapolated to that of the solvent, also it increases with the molecular weight of the polymer.
5) The activation energy of flow abnormally increases above a critical concentration of solution.This critical concentration is propotional to .

View full abstract

In order to obtain isotactic polyvinyl esters, acylation of polyvinyl ether (presumably isota-ctic) using an organic acid anhydride and a Lewis acid was tried.Vinyl benzyl ether which has a cleavable ether bond, was chosen as a monomer and synthesized by the Reppe process. White nontacky crystallizable polyether was obtained in a low temperature polyphase polymerization following Murahashi's method using trifluoroboron etherate as a catalyst. Acetylation product of the polymer with acetic anhydride and stannic chloride was soluble in methanol and acetone unlike the original polyvinyl ether. From Infrared spectrum study and analytical results on the product, it was recognized that substitution of the benzyl ether group to acetate group proceeded almost completely.X-ray pattern and infrared spectrum of the polyvinyl acetate obtained agreeded well with those of ordinary polyvinyl acetate obtained by free radical polymerization, where no sign of crystallinity was observed.
The acetylated polymer was hydrolyzed in sodium hydroxide methanolic solution.The hy-drolyzed polymer was soluble in water.Its degree of polymerization was estimated to be about 500 from viscosity measurement of aqueous solution.

View full abstract

Crystallizable and noncrystallizable polymers were prepared from vinyl tert-butyl ether using Ziegler catalyst and stannic chloride as initiator respectively. Two types of polyvinyl tertbutyl ethers (PVtBE) were acetylated by means of acetic anhydride and stannic chloride or zinc chloride and then saponified to give polyvinyl alcohol.Two types of polyvinyl alcohol thus obtained were formylated using formic acid.From analytical results and infrared spectra studies on the products, it was shown that the formylation proceeded almost completely resulting to polyvinyl formates (PVF).
PVF derived from crystallizable PVtBE was crystallizable while PVF derived from noncrystallizable PVtBE was noncrystallizable.The crystallizable PVF gave sharp fiber diagram and the repeat distance along the fiber axis was 6.55Å showing that the regular sequences in the polymer possessed isotactic configuration.
Previously we found that PVF obtained by free radical polymerization at low temperature was crystallizable and supposed the existence of syndiotactic structure from the identity period-5.0Å.Thus isotactic and syndiotactic PVF are prepared and confirmed by x-ray examination for the first time.Syndiotactic propagation in the free radical polymerization of vinylesters is enhanced over isotactic propagation by decreasing polymerization by decreasing polymerization temperature.
Stretched films of isotactic and syndiotactic PVF were subjected to heterogeneous hydrolysis. Both polyvinyl alcohol films obtained gave fiber patterns which resemble each other and the identity period calculated was 2.5A in both samples.

View full abstract

The hardening reaction of the polyester resin which was made of two moles of glycerine and three moles of 3. 6-endomethylene-1. 2. 3. 6-tetrahydro-cis-phthalic anhydride has been analysed from the solubility of the product for acetone and ethanol.
The mechanism of hardening reaction in the gel phase was discussed. The relationship between the extent of reaction in soluble parts and the yield of insoluble resin was obtained.

View full abstract

The infrared dichroism of a highly oriented film of polyacrylonitrile (PAN) was measured. Some differences were found between the detailed features of the spectrum of the present measurements and that reported by Krimm et al.The 1, 359 cm^-1 band reported as a single π band by Krimm et al. was found to be doubletts: 1, 362 cm^-1 (σ) and 1, 355 cm^-1 (π) The infrared dichroism was also found at the bands of absorbed water on the PAN film.

View full abstract