Alkali treatment is a novel method whereby “Tetoron” fabrics may be uniformly reduced in weight and so brought to a sheer thin state which gives them added value. The author reported the effect of temperature and caustic soda concentration on the rate of solution and the properties of treated fabrics in the previous paper. In this paper the mechanism of solution is discussed through the variation of rate constant of solution with OH-concentration, the degree of orientation and crystalinity of fibers, and the offect of the presence of alcohol on the rate constant. (1) Solution of “Tetoron” in hot alkaline solution consits in topochemical hydrolysis of its ester linkages. The attack of OH- is most probable on the fiber surface owing to the hydrophobic character and compact physical structure of the fiber. Meanwhile OH- neutralizes and dissolves away terephthalic acid, the product of hydrolysis, from the reaction system. As the result, hydrolysis or solution proceeds gradually from the surface to the center of the fiber without attaining equilibrium. (2) At the same normality, the rate of solution decreases in the order of KOH, NaOH, LiOH. (3) In alcoholic caustic potash solution, alkoxide ions promote ester interchange and dissolve Tetron more effectively, which is illustrated by the difference of nucleophilic ability between hydroxide and alkoxide ions. The presence of water reduces the number of alkoxide ions and the rate of solution. (4) Drawing of fibers decreases the rate, while heat treatment increases it. Further experiments are required to explain this result.
In order to clarify why silk is so rapidly colored by light, and why irradiated silk becomes difficult to solve in its solvents such as cupriethylenediamine, some peptides separated from its hydrolyzate were studied. It was recognized that some of the peptides separated on the filter paper of chromatogram were colored to brown, one of them was colored to bright yellow, and others remained unchanged, when they were irradiated by sunlight or a fade-o-meter. “Browning” of silk is, therefore, a hybrid of above-mentioned changes. Some of unchanged peptides contain tyrosine in their component, though it is believed that this amino acid is the most influential cause of the browning. The peptide turned to bright yellow by sunlight is the only one which contains tryptophan. The browned peptides have something in common in the respect of containing tyrosine and glutamic acid in company. Two abnornal peptides were separated from the hydrolyzate of the insoluble part of irradiated silk. One of them contains much of dopa (dihydroxyphenylalanine) and a little of glycine and glutamic acid. Another peptide contains serine, arginine, alanine and glycine. It is interesting to note that dopa accumulates in this part, though its presence in irradiated silk is already known. Some discussion is offered with the suggestion that the insolubilization of irradiated silk might be-caused by cross-linking between dopa or serine residues of confronting polypeptide chains.
The ion exchange reactions of the carboxyl groups in cellulose, especially their fully exchanged conditions, were surveyed theoretically and experimentally with Ca++ ion. Formally it was known that a high concentration of the cation M++ and a low concentration of hydrogen ion H+ were favourable to the complete exchange in the required direction. But the strict relationship between M++ and H+ and absorption ratio was not clearly known. In this study it was found that the carboxyl groups in cellulose reacted as the weak acid exchange resin and the relationship between M++ and H+ and absorption ratio was as follows. (cf. Fig. 3) The minimum concentration of Ca++ ion and pH of the solution to exchange all the free carboxyl groups to metal form was determined.
The resonance frequency method has not successfully been applied for the determination of the bending Young's modulus E of a single filament of commercial viscose rayon. This is because that the cross sectional shape of the viscose filament is irregular and the observed data are highly dispersed. So the present authors devised to rotate the clamp attached with a test filament and to vibrate the filament in the four different directions, prependicular to each other in a plane. The corresponding four resonance frequencies read on each filament differ remarkably from each other, so the arithmetic mean of the maximum and minimum values among them is taken to calculate E. This reduces intensively the effect of the cross-sectional irregularity and shows very good results. The ratio of the standard deviation to the average of E is only 0.03_??_0.04, contrary to 0.3-0.4 of the corresponding values in the ordinary calculation, providing the denier of the filament is uniform. The reason is discussed.
In order to clarify the mechanical behaviors of stretch yarns, their load-elongation curves have been analyzed by employing an equation. This equation, developed from the one by H. W. Holdaway based on a helical spring model, is simpler than that of the Holdaway's. The results of the analysis give many important information concerning the relation between the structure and mechanical behaviors of stretch yarns.
When the loads are given on the upper shaft of the gum roller used for the dyeing and finishing is loaded, the roller bends and the pressure against the down gum roller does not distribute uniformly. In general, the crown is given to the roller in order to press the down roller uniformly. By measuring the contact width between the upper roller and with the down roller along the roller length, the pressure and the crown may be calculated.
In order to determine whether the structure of paper yarn should be considered as twisted body of fibers arranged neatly and in parallel like a plate, or as twisted body of a plate like a zinc plate, the following two cases were studied. First, the cracks on the surface of the taped zinc-plate, strain-lacquared and twisted; next, the cracks on the spiraled zinc-plate, strain-lacqured, and then twisted or tensioned. And the following results have been obtained. 1) The angle of cracks to the axis is 45° regardless of helical angle, when the plate is tensioned and twisted. 2) Bending moments on the plate works as shown in fig. 8 and 16. 3) Bending moments on the plate at tensioning and twisting are just opposite in direction.
Graft copolymerisation of ethyleneimine monomer on polyvinyl chloride (PVC) fiber was studied. It was found that ethyleneimine could be grafted as well as vinyl monomer by the γ-ray irradiation. Retardation by hydroquinone and air was not observed. Differing from usual vinyl polymerisation, its reaction mechanism is not considered as radical polymerisation. We also examined the possibility of the graft-copolymerisation of ethyleneimine on heat destroyed or hydroperoxyd polymer to ascertain the reaction mechanism. As the results, it might be supposed that the graft cepolymer would be formed by the additional reaction of ethyleneimine with-OH groups or COOH groups on the molecule generated by the irradiation of the polymer.
The absorption isotherms of triazole derivative from Congo Red (I)*, Sirius Supra Brown 3 RL (C. I. No.35760) (II), Diazo Indigo Blue 2 RL (C. I. No.34010) (III), and Sirius Supra Brown RL (C. I. No.34035) (IV) determined under the same condition described in part IV. (I) and (II) do not contain conjugated chains which promote the coplanarity of the aromatic nuclei by resonance and probably favour the hydrogen bond formation by the groups at the ends of the conjugated chains. (III) and (IV) contain conjugated chains terminating at one end with these groups. The mean standard affinities of (I), (II), (III) and (IV) were 5.6, 6.2, 5.1 and about 4.5kcal. respectively. The view given by Vickerstaff (Vickerstaff; “Physical Chemistry of Dyeing” 2nd, edition. 183 (1954) breaks down for these dyes.