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Volume 26, Issue 8
Displaying 1-7 of 7 articles from this issue
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Tsuyoshi Kiyotsukuri, Hirozo Hasegawa, Rikizo Imamura1970 Volume 26 Issue 8 Pages 349-355
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSWet spinning of nylon 6 was studied by using 90% phenol aqueous solution as solvent and NaOH aqueous solution as coagulant. The optimum spinning conditions obtained for molecular weight of 3×104, nozzle of 0.5mmφ, coagulating bath length of lm and spinning speed of 10m/min, are as follows; coagulating bath temperature: 50°C, coagulating bath concentration: 4% and polymer concentration: 20%. Side and cross-sectional microscopic features, density, area ratio and mechanical properties of the wet spun filaments are considerably affected by spinning conditions. Molecular weight of polymer has also a large effect on spinnability, and in the case of nylon 6, molecular weight required for good mechanical properties is more than 2×104. Wet-spun filament can be drawn about 6 times in water at 65°C in spite of its higher density and crystallinity, and oriented X-ray fiber diagram is obtained for drawn and heat treated samples.
It is concluded that when spinning, drawing and heat treatment conditions are chosen adequately, the wet-spun fibers have good mechanical properties as that of the melt spun fibers. In addition, dyeing rate and moisture regain of wet spun fibers are larger than those of melt spun fibers. The cause of this behavior is discussed in terms of the cross-sectional and fine-structural characteristics of the wet-spun fibers.View full abstractDownload PDF (2777K) -
Tsuyoshi Kiyotsukuri, Hirozo Hasegawa, Rikizo Imamura1970 Volume 26 Issue 8 Pages 356-362
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSWet spinning of nylon 6 with molecular weight of 3×104 was studied by using five solvent systems of phenol (Ph), o-chlorophenol (OCP), sulfuric acid (SA), formic acid (FA) and dichloroacetic acid (DCA). Each of the solvent systems except OCP contained 10% water.
It is supposed from the data of solubility parameter, intrinsic viscosity, and Huggins' constant that FA, SA and Ph are very good, OCP is fairly good, and DCA is rather poor solvent for nylon 6. Coagulating behaviors of phenolic solvent systems (Ph and OCP) differ from those of other solvent systems, and it is expected that phenolic solvent systems results in the homogeneous and dense fiber structure, and other solvent systems results in the inhomogeneous and sponge-like coarse fiber structure.
The results of wet spinning are as follows; Fibers from Ph and OCP solvent systems have the homogeneous structure and good mechanical properties at lower alkali concentration in coagulating bath. Fibers from FA solvent system have the skin-core structure similar to viscose rayon, and have extraordinary low densities probably due to the presence of many voids. But when they are drawn, their fiber structure turns to homogeneous and their densities increase remarkably. The mechanical properties of drawn fibers from FA solvent system are best among five solvent systems. Fibers from DCA and SA solvent systems have the coarse fiber structure with macro-voids, and poor mechanical properties.
Moisture regains of wet spun fibers are generally greater than those of melt spun fibers, but vary considerably depending on solvent systems. Moisture regains of fibers from DCA and FA solvent system depend remarkably upon relative humidity, and that from FA solvent system decrease with drawing, while that from Ph solvent system depend slightly upon relative humidity, and increase with drawing. These intresting hygroscopic behaviors are probably due to the finestructural characteristics such as micro-voids which may be influenced by the type of solvent and the drawing ratio.View full abstractDownload PDF (2647K) -
Toru Takahashi, Ichiro Sato1970 Volume 26 Issue 8 Pages 363-368
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe orientation distribution of crystalline phase in the overall directions of cellophane is discussed quantitatively in terms of the degree of biaxial orientation function.
The orientation of the structural units in cellophane are closely related to the some mechanical and physical properties, and are important in terms of production and quality. It is desirable of course that the cellophane as a packaging material should be less in its ununiformity in the orientation of the structural units in the overall directions. But it is also desirable that it should be less in the anisotropy of mechanical properties and swelling; accordingly the difference between the values of _??_ and _??_ of each crystallographic axis should be small.
On the other hand, in terms of the adhesive properties or the reactivity in graftcopolymerization of vityl monomers, it is desirable that the value of _??_ should be close to 1.0.
The results of the experiments suggest that it is to some extent possible to establish the production conditions of cellophane to satisfy these purposes.View full abstractDownload PDF (341K) -
Kiroku Komatsu, Akira Katayama, Nobuhiko Kuroki1970 Volume 26 Issue 8 Pages 369-375
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSNickel-modified polypropylene fibers were dyed with 2-(6-ethoxy-2-benzthiazolyl-azo) p-cresol (I) in the presence of dispersing agent and the absorption isotherms were determined at 80° and 90°C. The resulting isotherms consisted of two parts, that is, a curved and a linear part. The linear part showed clearly the saturation.
The following investigations were carried out to examine the states of the dye (I) in the fiber.
(1) The result of the continuous variation method showed that the dye (I) formed 1:2 chelate compound with nickel in an aqeous alcoholic solution.
(2) The polypropylene film containing nickel stearate was dyed with the dye (I) and absorption spectra of the dyed film were measured. From the results of the absorption spectra it was concluded that the unchelated and chelated dye were present simultaneously in the film.
(3) Two nickel chelated dyes were synthesised by chelating the dye (I) with nickel stearate in benzene and with nickel sulfate in an aqueous alcohol. The IR-spectra showed that both the chelated dyes thus obtained were identical. The combining ratio of nickel to the dye (I) was determined to be 1:2 by the element analysis.
(4) When the nickel modified fiber was dyed with 0, 0-dihydroxyazobenzene derivative forming 1:1 chelate compound with nickel, it was found that the saturation value of this dye was about half of that of the dye (I).
From these results it is assumed that the dye (I) forms 1:2 chelate compound even in the hydrophobic environment such as polypropylene fiber and the equilibrium between unchelated and chelated dyes is established in the fiber.
The linear part of isotherm might correspond to the isotherm of the unchelated dye and the curved part to that of the dye chelated with nickel in the fiber.
The curved part was treated by Bjerrums method and the equilibrium constants of the chelate formation in the fiber were calculated graphically. From these results the thermodynamic parameters to the chelate formation of the dye (I) with nickel were obtained.View full abstractDownload PDF (429K) -
Izumi Fumoto, Akira Katayama, Nobuhiko Kuroki1970 Volume 26 Issue 8 Pages 376-381
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIsotherms were measured for distributions of model disperse dyes (benzene, azobenzene, p-amino-azobenzene, p-nitroazobenzene, 4-amino-4′-nitroazobenzene, 4-N-methylamino-4′-nitroazobenzene, and 4-N, N-dimethylamino-4′-nitroazobenzene) between water and n-heptane and between water and 3.5% chlorinated n-heptane at various temperatures. From the results the thermodynamic parameters were calculated for the process which consists of the transfer of one mole of the dye molecule from n-heptane to 3.5% chlorinated n-heptane.
Dye in n-heptane (mole fraction) → Dye in 3.5% chlorinated n-heptane (mole fraction)
The unitary free energy changes accompanied by the process were all negative. This indicates that the dye molecules were more stable in chlorinated n-heptane than in n-heptane. From the thermodynamic parameters obtained in this work the interaction between the dye molecule and chlorinated n-heptane molecule was discussed. It was concluded that the ability of the chlorine atom of chlorinated n-heptane to form hydrogen-bonds with proton-donating groups of the dye molecule might be a main source of the stability of the dye molecule in chlorinated n-heptane.
The fact that an introduction of an amino group into the dye molecule caused a marked increase in enthalpy change supported this conclusion.View full abstractDownload PDF (414K) -
Izumi Fumoto1970 Volume 26 Issue 8 Pages 382-388
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSPolyolefine were treated with bromine gas or bromine aqueous solution in the presence or absence of light. Crystallinity and crystallite size of the bromine treated polyolefine fiber were determined by means of X-ray diffraction. The results show that bromine can penetrate not only through the amorphous region but also into the semi-crystalline region of polyolefine fibers. The bromine treated polyolefine fibers contained less than 4% of bromine and showed no decrease in tensile strength. On the other hand, the bromine treated polypropylene film contained about 10% bromine and showed a marked swelling in water and devitrification.
In the infrared absorption spectra of the bromine treated polyolefines there were weak absorption bands due to C-O-, C=O and H2O. The presence of C-Br bond, however, was not cleared in this investigation. This fact suggests that most of bromine atoms in the bromine treated polyolefine are not chemically bonded with the polymer, but merely absorbed physically on the internal surfaces of the polymer, presumably in the form of Br2 or HBr.
The bromine treatment had a marked effect on the dyeing property of the polyolefines. That is, the bromine treatment considerably increased an equillibrium dye up-take of disperse dyes on the polyolefines. This increment of dye up-take might be attributed to the following factors:
a) an increase in swelling of the polymer,
b) interactions between disperse dyes and the polar groups in the polymer, such as C-O, C=O and C-Br, resulting form the treatment with bromine.View full abstractDownload PDF (489K) -
Mikio Karasawa, Minoru Sekido, Noriko Choji1970 Volume 26 Issue 8 Pages 389-396
Published: August 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIn the previous papers 1), 2), the mixture dyeing of 6-nylon and acetylated 6-nylon with mixtures of monobasic dye acids were reported.
In the present paper, the adsorption in the single dyeing of dibasic and tribasic dye acids has been studied. Then, the mixture dyeing of mono-, di- and tribasic dye acids has been examined in detail, to discuss their behavior “Blocking effect” in mixture dyeing on the ground of the results obtained in the single dyeing.
The dyes used are C. I. Acid Orange 7, Blue 25, Red 88 (monobasic), C. I. Food Yellow 3, C. I. Acid Blue 45 (dibasic) and C. I. Acid Red 18 (tribasic).
The adsorption isotherms of the dye acids in single dyeing and mixture dyeing for 6-nylon were determined at 90°C.
The results obtained are as follows:
1) From the adsorption isotherms in single dyeing (Figure 1), it is suggested that the adsorption of di- and tribasic dye acids is similar to that of monobasic dys acids on 6-nylon, that is, of L+C type proposed by Giles.
2) Assuming that the adsorption of dye acids on 6-nylon is of L+C type, the constants [S], a and k in the equation (1) can be calculated from experimental data of single dyeing (see Table 2).
3) The adsorption isotherms of a mixture of monobasic dye acids (D1, D2), or dibasic dye acids can be calculated from the equation (2) by using the constants [S]′, [S2]′, a1′, a2′ and k1′, k2′ calculated from the equation (3)_??_(5) where N1 and N2 are numbers of equivalent of D1 and D2, respectively, and the equivalent ratio N1/N2 is limited from 1/2 to 2.
4) In binary mixture dyeing of dye acids (D1, D2), adsorption ratio [D1]φ/([D1]φ+[D2]φ), where [D1]φ and [D2]φ, are the amounts of equilibrium adsorption, varies with pH of dyebath, and it is thought that the variation of the adsorption ratio involves the blocking effect in mixture dyeing. When the both differences in a and k between each dye acid in single dyeing were small, the blocking effect was very small. On the contrary, when the one or both of these differences were great, the effect was large (see Table 3, Figure 11, 12).
5) It has been found that the blocking effect in the binary mixture dyeing can fairly well be estimated from the constants obtained in single dyeing of each dye acid.View full abstractDownload PDF (560K)
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