The chemorheological and dyeing behaviors of spandex fiber were studied.
The equilibrium adsorption of acid dyes on the spandex fiber at 70°C and 90°C was investigated. The dyes used are C. I. Acid Orange 7, Blue 25 (monosulphonates) and C. I. Food Yellow 3 and Acid Blue 45 (disulphonates). The stress relaxation measurements were carried out in air at 120°C for 10 hrs. under 100% or 10% elongation on the wet-treated and dyed spandex fibers.
The results obtained are as follows:
(1) From the adsorption isothers (Figures 2 and 3), it is suggested that the adsorption of dye acids on the spandex fiber at 70°C is of a L+C type proposed by Giles. The adsorption isotherms at 90°C are irregular compared with that at 70°C. But the tensile strength and elongation of the fibers dyed at 90°C decrease remarkably (Table 2). The dyeing behavior at 90°C may be due to the degradation of the spandex fibers.
(2) The stress relaxation data of the wet-treated and dyed spandex fibers are plotted in the forms of f(t) and f(t)/f(0) vs. log t (Figures 5 to 8). The spandex fibers dyed with disulphonated dye acids and treated with water have the almost same initial stress values (f(0)) as those of the untreated fibers. On the other hand, the fibers dyed with monosulphonated dye acids have lower initial stress values (Table 2). However, the stress relaxation curves (f(t)/f(0) vs. log t) of the untreated, wet-treated and all dyed fibers are essentially identical. The decay of the stress (Fig. 8) therefore seems to be independent of the initial concentration of network chains (n(0)). As indicated by Tobolsky and others, the fact that f(t)/f(0) is independent of n(0) suggests that cleavage takes place at the network junctures or at the neighbourhood for the untreated, wettreated and all dyed fibers. At present, it is not possible to identify the broken linkages responsible for stress decay.
(3) The intermittent measurement at 120°C shows no stress decay up to 10 hrs. for both the dyed spandex fibers and the untreated ones. It is suggested from this fact that the stress relaxation in the deformed state might be attributed to the cleavage of the network junctions, which are easily reformed after the removal of stress.

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The present paper describes the changes of the orientation in the crystalline region of cellulose films in the ceric salt-initiated graft copolymerization of acrylamide. The biaxial orientation of the crystallographic axes of the cellulose II was evaluated by the methods given by Wilchinsky, Stein and Kawai-Takahara. The crystallites suffer large strains by the formation of poly-acrylamide and a grain boundary migration occurs. As the result, their texture shifts gradually towards random orientation. The X-ray diffraction intensity of the cellulose crystallites begins to weaken at the graft ratio of 140_??_150%, and it completely disappears at above 250% grafting. From these results, it is concluded that Cellulose II crystallites are fractured in the highly grafted samples.

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Graft polymerization of methyl methacrylate (MMA) onto viscose rayon in the absence of initiators was investigated.
Graft polymerization was carried out in emulsion and aqueous solution. Polymerization proceeded smoothly and weight increase of rayon was higher than that of the original cellulose (cf. Part 1. of this series). Non-ionic surfactant as an emulsifier was more effective than ionic ones. When Neugen YX-500 and Neugen ES-120 were used as an emulsifier, more than 400% of weight increase of rayon favarable was attained under the favarable conditions, and in the case of polymerization in a sealed tube in vacuum the weight increase of rayon was also about 1000%.
The grafted rayon, extracted by acetone for 30hrs., was ground into powder in dry ice-methanol and then reextracted with acetone for 30hrs. by using a soxlet apparatus. The existence of homopolymer in rayon was indicated by the reextracted PMMA which was about 15% of the PMMA contained in the powdered grafted rayon. The grafted PMMA was isolated from cellulose back bone by using acid hydrolysis. The viscometric molecular weight of the isolated grafted PMMA was in the order of 10⁶.
The physical properties of grafted rayon varied with increase of grafting. Some properties of grafted rayon (tensile and loop strength, loop and knot elongation) depend on the polymerization condition (polymerization medium, quantities of rayon and emulsifier).

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The interactions of β-naphthalenesulfonic acid with methanol, ethanol, iso-propanol, n-propanol, N-monomethylformamide, N, N-dimethylformamide, N, N-diethylformamide, N-monmethylurea, N, N-dimethylurea and N, N′-dimethylurea were studied in water, deuterium oxide, dioxane, and formamide solutions by using NMR spectroscopy. The chemical shift, v₀, of methyl protons of hydrotropic agent in pure solvent and v in solution of various concentrations of β-naphthalenesulfonic acid were measured. The shift, Δv (=v-v₀), were plotted against the concentration of additive β-naphthalenesulfonic acid.
It is observed that the proton chemical shifts of the alkyl chains of these hydrotropic agents in the presence of the aromatic compound are displaced to higher field (relative to external TMS). The magnitude of the upfield shfit is much larger in water or deuterium oxide than that in dioxane or formamide solution. The Δv values for alcohols (1) and formamides (2) series in aqueous solutions are in the following order, (1) methanol<ethanol<iso-propanol<n-propanol, (2) N-monomethylformamide<N, N-diethylformamide≤N, N-dimethylformamide. An addition of urea to the aqueous solution causes a decrease in Δv.
These large upfield shifts can be explained by the proximity of the aromatic compound which has large anisotropy of the magnetic susceptibility to alkyl groups of the hydrotropic agents.
The results obtained in this work are consistent with the previously observed thermodynamic parameters.
From a consideration of the above results it seems most reasonable to conclude that there exist hydrophobic interactions between nonpolar parts of the aromatic compound and alkyl chains of these hydrotropic agents.

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The contribution of structural salting-out effect to the total salting-out phenomena was studied in this work.
The solubilities of azobenzene and p-hydroxyazobenzene in water and various inorganic electrolytes-NaCl, LiCl, NaNO₃, NaClO₄, and NaSCN-aqueous solutions (1 mole/l) were determined at 5°C intervals from 5° to 40°C.
From the results the thermodynamic parameters for the process (A) which consists of a transfer of one mole of the solute from water to the aqueous inorganic electrolyte solutions were calculated.
The solubilities of the solutes in an aqueous 6 mole/l urea solution and in aqueous 6 mole/l urea-1 mole/l electrolyte solutions were determined at the same condition as that for water. Using the data of solubilities the thermodynamic parameters for the process (B) which consists of a transfer of one mole of the solute from the aqueous 6 mole/l urea solution to the aqueous 6 mole/l urea-1 mole/l inorganic electrolyte solution were calculated.
By comparing the free energy changes for the process (A) with those for (B) it was found that an addition of urea into aqueous inorganic electrolyte solutions causes a decrease in salting-out phenomena.
Structural salting-out comes from a structural repulsion between different kinds of the water structure around non-polar solutes and that around ions. It has already been established that urea breaks icebergs around hydrophobic parts of solutes in an aqueous environment.
Various influences of urea on the salting-out effect of inorganic electrolyte were discussed and the decrease in salting-out phenomena in an aqueous urea solution was explained in terms of iceberg breaking effect of urea.
In an aqueous urea solution the iceberg around the solute should be disrupted by the action of urea. This disruption of the iceberg should cause disappearance of structural salting-out effect.
The difference between free energy changes for the processes (A) and (B) are attributed to the contribution of the structural salting-out effect.

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The following new results have been obtained by the differential thermal analysis of silk materials:
1. All the silk fibers show an initial endothermic reaction at about 100°C on account of the evaporation of absorbed water. The second endothermic peak occurs at 305°C in domestic silk and around 350°C in wild silks. Silk is known to consist of polypeptide chains in a predominantly extended configration with the intermolecular hydrogen bonding. The second endothermic peak may be attributed to the destruction of β-configuration.
2. For Bombyx fibroin, α-β transition during the wet thermal treatment begins to occur around 120°C, and the α-fibroin almost changes to the β-fibroin at 130°C. On the other hand, the α-fibroin begins to change to the β-form around 240°C during the dry thermal treatment and completely changes to the β-form at 260°C. But this α-β transition could not be detected by DTA.
3. The α-β transition for native Tussah silk fibroin in silkgland can be detected by DTA. Its endothermic peak occurs at 54°C. This behavior is in agreement with the result of X-ray diffraction. For the α-form of coagurated fibroin, an initial endothermic peak appears at about 100°C due to the loss of absorbed water. The α-helical structure of fibroin begins to be destroyed at about 160°C, and small endothermic peak by the α-β transition appears at about 200°C. The next major reaction is also endothermic and begins around 270°C. A single peak at 336°C is obserbed for coagurated fibroin. It is thought that these endothermic reactions may arise from the decomposition of the β-fibroin component.
4. The thermogram obtained from poly-L-alanine is very similar to these from wild silks. The endothermic peaks appear at 95°C and 353°C and a exothermic peak occurs at 342°C. The X-ray diffraction powder diagrams show that crystallites of poly-L-alanine begain to show the β-form at 280°C, and become perfectly β-form at 324°C.
5. According to the DTA thermograms obtained from Bombyx sericin, the sericin extracted with water at 120°C for 1 hr. shows endothermic reaction starting gradually around 160°C and with the peak at 200°C. On the other hand, the coagurated sericin in silkgland shows the peak at 223°C. These endotherms correspond to the temperature of disappearance of birefringence for the sericin. Therefore, these endothermic peaks show the decomposition point of the sericin crystallites. It is thought that the difference of endothermic peak depends on the size of crystallites of sericin.
6. When silk fibers are heated in water under pressure at the temperature higher than 100°C, the second endothermic peak showing the decomposition of β-structure is shifted to higher temperature with decreasing temperatures. This phenomena are explained by the crystallization.

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