The relations between the density of felt and the mechanical and frictional properties and crimps were statistically tested. The values of the physical properties used are previously reported (XXXIX). As the results, the greater the density of felt the lower is the resilience, and the higher the concentratoin of NaNO₂ (0_??_0.4%) in the carrotting solution the lower is the resilience.

View full abstract

Resilience is suppressed as the twist setting treatments are given to yarn for finishing. But S (twist set percentage of yarn) is not a constant.
The results on the yarn given by varied bath temperatures are as follows:
(1) At 10°C S of worsted yarn decreases from 95% to 85% and S of woollen yarn from 91% to 43%.
(2) This declining tendency goes on up to 40°C.
(3) As the setting property of fibers in woollen yarn bigins to appear at 60°C, value S rises again.

View full abstract

Purified cotton linters presoaked in AcOH, were acetylated at 70° and 90°C with a minimized amount of Ac₂O and H₂SO₄.
(1) The average degrees of polymerization of the triesters obtained were between 115 and 180 at 70°, and between 105 and 120 at 90°C. The acetylation was carried out using either 250% or 300% of Ac₂O, based on the weight of cellulose. The rate of the reaction is more strongly dependent on the amount of H₂SO₄ than on the amount of Ac₂O. The minimized amount of Ac₂O is 4 moles per glucose anhydride, and the value is almost the theoretical one, as a little more of Ac₂O than the theoretical value (3 moles per glucose anhydride) is usually required to acetylate the low molecular compounds which are decomposition product of cellulose by acetylation at higher temperatures.
(2) The more the amount of H₂SO₄ and the higher the temperature of the reaction, the faster the rate of reaction increases. The triesters were obtained by 0.7% and 0.5 of H₂SO₄ based on the weight of the cellulose at 70°C for 90 and 120 minutes, respectively.
(3) The minimized amounts of H₂SO₄ to obtain the triesters are 0.5% at 70°C and 0.2% at 90°C. The difference in these minimized amounts may be caused by the fact the rate of acetylation is determined by the cyclic reaction of H₂SO₄ which is affected by temperature.

View full abstract

Regarding the process of microstructure formation of viscose fiber, the fundamental study was done with Na-xanthate model filaments which contained Dithizone (Diphenyl-thiocarbazone) as indicator of Zinc. When the filament was immersed in various H₂SO₄-ZnSO₄ baths or H₂SO₄-ZnSO₄-Na₂SO₄ baths, on the cross-section of the filament clear periodic ring, which consisted alternately of Zn-xanthate layers and directly regenerated layers, was observed.
This periodic ring formation is influenced intricately by diffusion velocity of H₂SO₄ and ZnSO₄ and regeneration reaction velocity. In case that any of them is predominent, periodic ring does not appear. There is optimum combination of these factors.
The mechanism of this ring formation, which is related to the microstructure of the fiber, is considered from the view point of diffusion phenomena of reagents.

View full abstract

Acetylation catalysts are sorbed by cellulose in acetic acid or acetic anhydride solution, and the phenomena are important in the acetate industry to the pretreatment or acetylation of cellulose. In this report, the influence of any solvent mixed in acetic acid or acetic anhydride upon HClO₄ sorption, electric conductivity, or acetylation rate was studied, and their relation or mechanism was considered.
Various solvents can be separated into 2 series: I-series includes hydrocarbons and chlorhydrocarbons (cresol, nitrobenzene also), II-series those containing -0-, =CO, -CN groups. I-series solvents are indifferent to HClO₄ and so have influence of dielectric constant and dilution upon the ionization and dissociation of HClO₄-AcOH complex, i. e. smaller D. K. brings smaller conductivity, larger sorption, or larger acetylation rate. II-series solvents combine with HClO₄ by hydrogen bonding into complex formation and decrease HClO₄ sorption or acetylation rate almost independently of D. K. further than I-series.

View full abstract

The Procion Black HGS procedure, originally developed for the differentiation of the skin-core effect in viscose rayons, is found to give a characteristic staining on the cross-sections of 6-nylon filaments subjected to the irradiation in Fade-o-meter. As a result of comparative studies with several other microscopical staining methods, it is indicated that the photodegradation of 6-nylon filaments proceeds in a highly heterogeneous manner and is essentially an oxidative reaction due to photoactivated oxygen, giving rise to the formation and accumulation of certain aldehydic substances as relatively stable intermediates.
By means of electron microscope a marked microfibrillar structure is revealed of 6-nylon filaments having undergone a long period irradiation in Fade-o-meter. The photo-oxidative degradation must attack preferentially against the interfibrillar regions, thus unmasking the inherent fiber structure of nylon filaments.

View full abstract

Generally it is accepted that fibres are built up from fibre-forming high polymers. However, fibres also contain some of low-polymers; namely dimer, trimer, and tetramer, etc. We examined the effects of heat-treatment at low pressure on polyamides, polyesters and wool. When these fibres are heated to 80 -200°C at pressure of 10^-2 to 10^-8 mmHg, they give off low polymers as well as absorbed gases. Furthermore, the melt-spinning materials in synthetic fibres are evaporated in such conditions. For instance Nylon 6 is evacuated for one hour by a rotary pump at 100°C and Tetoron for one hour at 135°C. The sublimed materials are collected and crystallized on the inner wall of the vacuum system, and examined by microscope. Thus treated and untreated fibres were dyed in the exactly same condition and their cross-sections were compared through microscope. The treated fibres are found much better dyed. This fact suggests that electron-microscopic pores, or say artificial micellar spaces, are produced in surface-layer of these fibres by the above-mentioned treatments.

View full abstract

The sulfidation-resistance value (S-W), proposed by Bartunek as a measure of reactivity of dissolving pulp, is the amounts of undissolved residue of pulp after emulsion xanthation at the definite concentration of sodium hydroxide solution, sufficient to mercerize cellulose, with 25% of carbon disulfide based on the pulp. So the Bartunek's S-W shows only a point on the emulsion xanthation solubility curve (S-W curve) as a function of the amounts of carbon disulfide added. In the previous paper, the significance of S-W curve as a measure of reactivity or filterbility of viscose from the pulp was studied.
In this paper, the relation between S-W curve and Bartunek's S-W is studied in order to research the significance of Bartunek's S-W as a measure of reactivity of dissolving pulp. The results are as follows:
Bartunek's S-W correlates not only to the amounts of carbon disulfide required for dissolving 50% of pulp, but also A₁, A₂ and A₃. Here, A₁ and A₂ are the average “dissolved-distances” per unit amount of carbon disulfide on the first and second inflexion points of calculated S-W curves respectively, and A₃ is the average amount of the dissolved per unit amount of carbon disulfide during the reaction (see Fig. 5). However Bartunek's S-W has no correlation to the characteristics of S-W curve, obtained in the previous paper as to the state of viscose solution.
From the above, the following conclusion may be drawn. Bartunek's S-W gives only an average measure of solubility in emulsion xanthation, and has no definite significance as a measure of reactivity of dissolving pulp or a measure of filterbility of viscose prepared from the pulp.

View full abstract

Acrylonitrile fibre can be dyed with acid dyes by the cuprous ion technique, and cuprous ion be produced by the reduction of cupric salt. In the case of applying hydroxylamine sulphate as most suitable reducing agent, acid dye in the bath is reduced simultaneously, and decomposed. Acid dyes used in the present experiment are monoazo dyes, and following results are obtained:
When dyes are reduced in boiling solution containg hydroxylamine sulphate, aromatic amines are formed according to the theoretical rate of the third order reaction. However, the rate of reaction and the order of rate are strongly dependent on the temperature and at 90° or 80°C. occurs the reaction of the second order or succesive reactions. The experiments indicated that the number of sulphonic groups in the chemical structure of dye and its substitute position have a large effect on the rate of reaction. The rate constant increases rapidly as the number of sulphonic group is raised, and the concentration of hydroxylamine sulphate has an effect on decomposition of dye. But the pH of the solution has a relatively little effect, if the solution has a pH of less than 5.0.

View full abstract

The retarding effect of surface active agents on absorption of acid dye with cuprous ion technique is discussed in relation to the rate of dyeing, and is analysed particularly from the viewpoint of the modern theory of diffusion into fibre.
Anionic auxiliary agents, which are expected to have an affinity between the fibres, act so as to retard the absorption of dye, in proportion to the concentration in the bath, and serve the purpose of obtaining more even dyeing. The retarding action of nonionic auxiliary agents is found, to a certain extent, to depend upon their concentration. Even a small addition, less than 1% on the weight of fibre, to a dyebath are usually regarded as unwise, as it promotes the absorption of dye. However, since there appeares retarding action at 2.5 and 5%, it seems they react with dye. In each case, surface active agents react upon positively charged fiber that produced cuprous ion co-ordinated with nitrile group. It shows closely analogous properties to the dyeing of wool with acid dye. The rate of dyeing curves at the temperatures, 90° and 100°C., which are usual for the dyeing, are analysed by diffusion equation in the non-steady state, and nearly equal diffusion constants are obtained by applying various theoretical equations.

View full abstract

Changes of the mechanical properties and durabilities of cotton and viscose fabrics finished with emulsion copolymers of N-methylolacrylamide (MAM) and acrylic esters, including ethyl and butyl acrylate, were examined. The results thus obtained are as follows.
(1) Durabilities to launderings of the polymer-treated and acid-cured fabric increase with higher MAM-content in polymer, partly due to the improvement of the tensile strength and elastic properties of the copolymer through the formation of cross links between polymer chains by acid-cure, and partly due to the reaction of methylolamide groups of the polymer with -OH groups of cellulose molecules.
(2) Such improvement of the tensile strength and elastic properties of the cured copolymer also causes the elevation of wrinkle recovery of cotton and abrasion resistance of both fabrics.
(3) In spite of the remarkable changes of the stress-strain properties of acrylate polymer with its copolymerization with only a minor amount of MAM, followed by acid cure, the treated fabrics do not show any marked change of such mechanical properties as wrinkle recovery and tear strength, which might be attributed partly to the decrease of the elastic recovery of the polymer at higher elongation due to the decrease of ultimate elongation by cross linking, and partly to a relatively small change of the ability of energy absorption of the polymer by such procedure.

View full abstract

When adhesion of rust occours to any fiber by any mistake during processing of textile, it can easily be removed by immersion into a diluted solution of oxalic acid. On the contrary, in the case of nylon it is found that these oxalic ferrates (ferrous oxalate and ferric oxalate) produce from rust is readsorbed in the solution. The higher the temperature is, the longer the time of immersion, the nearrer to pH 7, and then the adsorption of oxalic ferrates is increased.
The mechanism of the adsorption of the ferrates is based on Langmuir's absorption isotherm, and the ferrates on fiber change the colour of the fiber, degrade white nylon and produced britteness of the fiber on exposure to sunlight.

View full abstract