An apparatus to measure the dynamic tensile properties of textile fibers at mili cycle range of frequency by using hysteresis loop method, is described. Within the dynamic strain amplitude of 0.1, the mechanical properties of textile fibers can be represented approximately by the simple linear viscoelasticity, for example, by the complex dynamic modulus function. The dynamic complex tensile modulus of several textile fibers, such as cellulosic fibers, polyester and polyamide fibers, natural silk and some vinyl fibers were measured over the range of frequency from 1×10^-4 to 1×10^-2 cps. Generally, the real part of complex dynamic modulus decreased slightly, while the imaginary part increased considerably, both as frequency decreased. The results obtained here agree well to those from our earlier measurements ranging the frequencies of 10^-1 to 10⁸ cps.

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In order to obtain an evidence of the existence of intra-and inter-molecular hydrogen bonds in aqueous solutions of polyvinyl alocohol (PVA), viscometric measurements were made with aqueous solutions of PVA containing various contents of urea and NaOH, both of which have an ability to break hydrogen bonds. Intrinsic viscosity [η] increases with the content of urea in the concentration range studied. In the case of NaOH, [η] increases similarly with addition of it up to 6% of NaOH but decreases rapidly at this concentration. For the purpose of obtaining the information concerning “selective adsorption” of these agents to PVA molecules, the amounts of NaOH adsorbed by PVA films (heat-treated) were measured by means of an usual titration method. The equilibrium swelling ratio was also obtained as a function of the concentration of NaOH in the external solution. The concentration of NaOH in the gel phase are, in every case, less than that in the solution phase. This negative adsorption of NaOH implies that PVA molecules adsorb selectively neither Na ions nor OH ions and do not behave as a polyelectrolyte. In spite of the “salting out” effect due to the addition of NaOH, the equilibrium swelling ratio increases with the content of NaOH in the external solution. This fact seems to be attributable to the breakdown of the hydrogen bonded junction points between PVA molecules by NaOH. Similarly, the increase of [η] with the content of NaOH or urea is attributable to the breaking of intramolecular hydrogen bonds between OH groups separated by many intervening segments along the chain. On the other hand, the rapid fall of [η] at 6 NaOH is a manifestation of the existence of another type of intramolecular hydrogen bonds between near neighbor OH groups along the polymer chain.

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While the degree of crystallinity of unoriented polyethylene had been determined by Tobolsky, Matthews, Bryant and Aggarwal with the use of an X-ray counter, we measured the degrees of crystallinity and orientation of low and high density polyethylenes in various degrees of elongation. It was observed that they increased with the increasing degree of elongation and the samples of low density showed evidently lower degree of crystallinity (0.48-0.60) than that of high density (0.63-0.72).

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Copolymers of vinylalcohol and about 5 mol% allylalcohol (A-PVA) or isopropenylalcohol (P-PVA) were prepared and fractionated. The viscosity change of 10, 13 and 15% aqueous solutions of fractionated A-PVA and P-PVA was measured at 10°C, and compared with that of fractionated polyvinylalcohol (PVA). Gelation velocity of aqueous solutions of A-PVA and P-PVA were smaller than that of PVA. The formation of junction point in aqueous solution of PVA seems to be greatly affected by the presence of a small ammount of allylalcohol or isopropenylalcohol-group. Gelation velocity of aqueous solutions of PVA increases with increasing molecular weight, and are affected by the presence of a small ammount of PVA with higher molecular weight.

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The ζ-potential of polyvinyl alcohol fibers partially acetalized with glyoxylic acid, whose ionization constant was 2×10^-3, was determined in the aqueous solutions of sodium hydroxide or hydrochloric acid by the use of the streaming potential method. It was found that the ×-potential was of small negative value (nearly -10 mV) until neutralization point of acid groups was reached, where electric conductivity of the aqueous solution was below 3-10^-6 mho·cm^-1 and thereafter the negative ζ-poential increased with increasing concentration of sodium hydroxide. These phenomena may be due to the swelling and the counterion binding by the amorphous part which increases with the increasing degree of neutralization and through a maximum at the complete neutralization decreases, and to the adsorption of anion on the fiber surface.

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Polyvinyl alcohol fibers which bound strong acid were prepared by partial esterification using chlorosulfonic acid. Electrokinetic behavior of these fibers was found to be similar to that of the polyvinyl alcohol fibers partially acetalized with glyoxylic acid, but the negative ζ-potential of these fibers was smaller than that of the acetalized fibers. It may be due to the fact that the fibers of low degree of esterification can swell to a more considerable degree.

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The fine texture of the regenerated cellulose fibers prepared from viscose was studied by means of some physicochemical techniques. These samples prepared using three kinds of salt solutions which had different coagulation power on viscose, were so called isotropic model filaments. Not only the proportion by weight of crystalline materials, but the crystalline size and the numbers of the segments of the amorphous regions were depend upon the coagulating power. Details were discussed.

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A suspension polymerization of vinylchloride, in which lauroyl peroxide was used as a catalyst and polyvinylalcohol as a suspension stabilizer, was studied. The quantities of polyvinylalcohol adsorbed on the produced polyvinylchloride particles were nearly proportional to the polyvinylalcohol concentrations having been contained in the polymerization system, and not extracted with hot water in spite of the repeated washing operations. The relations between the average size of polyvinylchloride particles and polyvinylalcohol concentrations in polymerization system, was presumed.

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