Use of diluted viscose waste in the process of preparing complex yarn for aircraft fabrics

Conclusions The possibility has been established of using dilute viscose wastes in the process of preparing a spinning solution for spinning complex viscose yarns which are used in the manufacture of aircraft fabrics.Empirical equations have been obtained for calculating the change with time of ripeness indices and of free NaOH content of viscoses having an -cellulose concentration of 5.0–8.4% by wt., plus calculated dependences which ensure determining the optimum ripeness index for spinning for viscoses which have been diluted in the range indicated.It has been shown that, with decrease in -cellulose and NaOH content of the spinning solution, the stiffness of complex viscose yarn is increased.Translated from Khimicheskie Volokna, No. 3, pp. 48–50, May–June, 1986.     

Viscosity properties of concentrated viscoses

Conclusions The physico-chemical properties of viscose containing up to 15% -cellulose by wt. have been investigated.It has been noted that increasing the -content of viscose affects principally the viscosity of solutions, but shows up only a little in the other characteristics of the viscose.At -cellulose contents up to 13.5% by wt. viscoses retain homogeneity and can present immediate interest for technological processing on appropriate selection of such parameters as temperature and NaOH/-cellulose ratio.Translated from Khimicheskie Volokna, No. 5, pp. 45–47, September–October, 1987.     

Change in polydispersity of degree of esterification of cellulose xanthate during the process of viscose ripening

Conclusions A method of determining the polydispersity of the degree of esterification () of the cellulose xanthate in viscose has been proposed, plus an algorithm for calculating it.The change in density of distribution of in cellulose xanthate during viscose ripening over a period of 96 h at 16°C has been studied.It has been found that the dispersion in density of distribution of in cellulose xanthate continuously decreases during ripening.Translated from Khimicheskie Volokna, No. 1, pp. 18–21, January–February, 1989.     

The effect of carbon black filling and cross-linking in stretched SBR networks: a 2H-NMR study

Summary The line splitting v in ²H-NMR spectra of deuterated benzene in stretched crosslinked SBR depended linearly on the classical stretch term ² – 1/ for samples with and without carbon black filling. The ratio LS = v/(² – 1/) was measured in dependence on the solvent fraction . The extrapolated value L of this ratio at =0 gave a linear dependence on the inverse molecular mass 1/M_c of inter-crosslink chains. This was expected according to a simple model of chain dynamics and offers a further NMR-method for M_c-determination even in filled networks. However, the slope of the L(1/M_c)-line increases with an addition of carbon black which indicates a higher molecular order. Three reasons for this could be discussed. However, one of them is preferable.     

Effects of crystallinity and supermolecular formations on the interfacial shear strength and adhesion in GF/PP composites

Aim of this study was to screen the morphological effects on the interfacial shear strength (i) in glass fibre (GF) reinforced isotactic polypropylene (iPP) model composites. i was determined by a modified single fibre pull-out technique. It was established that the relation between i (5–6 MPa) and the yield stress of the iPP (y30 MPa) is at about 1:6 and that the i values were not influenced by the mophological superstructure set under isothermal crystallization conditions. Increased i was only observed when specimens were produced non-isothermally, by quenching (i9 MPa). This improvement could not be related to thermal shrinkage stresses. The enhancement in i was attributed to better wetting and improved adhesion due to the enlarged amorphous PP (aPP)-phase. A schematic adhesion model considering the wetting behaviour of aPP and iPP was proposed.     

Upwind searching for an odor plume is sometimes optimal

A model is presented that suggests that the optimal strategy for an animal walking or crawling on a substrate while searching for the source of a chemical carried by a shifting wind or current may be to move upwind (or against the current). The requirements are that (1) the current direction fluctuates rapidly within a range that exceeds 30 ° on both sides of the mean direction, and (2) the searching animal can move accurately up- or downwind and, once within the influence of the chemical plume, can move efficiently to the source. Under these conditions, an upwind search is shorter (on the average) by 0.9–0.3 of the range of influence of the chemical stimulus. Thus, this strategy is relatively more important when the total search path is short, i.e., when sources are typically close by. The mean length of the downwind search path is given by L _d =d +r[(1/E) + cos ]/2 and the upwind search path by L _u =d +r[(2/E) – (/sin ) – cos ]/2 whered is the starting distance up- or downwind of the source,r is the range of stimulus influence,E is the efficiency with which the searcher moves to the source within the influence of the plume,a is the angle of the maximum extent of wind direction from the mean, and the average, , is taken over all starting positions across the wind direction that lead to search paths that intercept the area swept by the plume.     

Evaluation of the purity of viscoses having various viscosities from their filterability through a screen

Conclusions A relationship has been derived which permits one to compare purities of viscoses having different viscoities on the basis of figures for their filterability through a screen having a mesh size of 71 × 71 .Thereupon the filterability of viscoses having different viscosities is recalculated to a filterability at a definite, selected viscosity.Translated from Khimicheskie Volokna, No. 2, pp. 21–22, March–April, 1988.     

Characteristics of Heterophase Radical Graft Polymerization of Methyl Methacrylate on Polymer Fibres

Graft copolymers with graft PMMA were synthesized using the Cu²⁺—H₂O₂ redox system. The conditions for obtaining graft PCA—PMMA and HC-PMMA of 40–60 composite composition with grafting efficiency at the 85% level are found. The effect of the polymer matrix on the kinetic and thermodynamic properties of graft polymerization of MMA is revealed. Possible schemes of the reactions of graft polymerization of MMA to polycaproamide and hydrated cellulose are proposed based on quantum chemical calculations of the enthalpy of formation of the graft copolymers.The research was conducted under MNTPP Project No. 203 Chemical Engineering (Section 2 General Chemical Engineering) in the scientific-industrial program Higher-Education Research on Priority Directions in Science and Engineering.__________Translated from Khimicheskie Volokna, No. 1) pp. 19–23, January–February, 2005.     

Lamellar Morphology of Poly(3-hydroxybutyrate)/Poly(ethylene oxide) Blends as Studied via Small Angle X-ray Scattering

The lamellar morphology of a melt-miscible blend consisting of two crystalline constituents, poly(3-hydroxybutyrate) (PHB) and poly(ethylene oxide) (PEO) have been investigated by means of small angle X-ray scattering (SAXS). The blend was a crystalline/amorphous system when temperatures lay between the melting point of PEO (ca. T _m ^PEO=60C) and that of PHB (ca. T _m ^PHB=170C), while it became a crystalline/crystalline system below T _m ^PEO. The crystalline microstructures of the blends were induced by two types of crystallization history, i.e. one-step and two-step crystallizations. In the one-step crystallization, the blends were directly quenched from the melt to room temperature to allow simultaneous PHB and PEO crystallization. The two-step crystallization involved first cooling to 70C to allow PHB crystallization for 72 h followed by cooling to room temperature (ca. 19C) to allow PEO crystallization. In the crystalline/crystalline state, two scattering peaks have been observed in the Lorentz-corrected SAXS profiles, irrespective of the crystallization histories, meaning that crystallization created separate PHB and PEO lamellar stack domains. One-step crystallization yielded lamellar stack domains containing almost pure PHB and PEO lamellae. Two-step crystallization generated almost pure PHB lamellar domains and the PEO lamellar domains with inserted PHB lamellae. In the crystalline/amorphous state, the composition dependence of the amorphous layer thickness (l _a), the presence of zero-angle scattering, and the volume fraction of the PHB lamellar stack (_s) revealed that both one-step and two-step crystallizations, generated the interfibrillar segregation morphology, where the extent of interfibrillar segregation of amorphous PEO increased with increasing PEO content.     

Adaptive control system for the viscosity of viscose

Conclusions A structure and algorithm have been developed for an adaptive system for control of viscose viscosity in the manufacture of artificial fibres.The control system has been introduced into the ACS TP for viscose tire cord manufacture of the Svetlogorodsk Khimvolokno PO.Translated from Khimicheskie Volokna, No. 5, pp. 22–25, September–October, 1986.     

A study of the acidic and catalytic properties of pure and sulfated zirconia–titania and zirconia–silica mixed oxides

Protonated pyridine (PyH⁺) was not found on ZrO₂ (Z) or ZrO₂–TiO₂ (ZT), but was detected on sulfated oxides (ZS, ZTS) by IR spectroscopy. In contrast, ZrO₂–SiO₂ samples containing about 30–80 mol% ZrO₂ showed Brønsted acidity both in nonsulfated (ZS) and sulfated (ZSS) forms. The total acidity was determined by NH₃TPD. Introduction of sulfate ions increased the sitespecific catalytic activity (TOF) in the conversion of cyclopropane or nhexane. The effect of sulfate ions was more significant on samples rich in zirconia. Results suggest that Zr is homogeneously distributed in ZS samples rich in silica. Zirconiabound dimeric sulfate, generating strong acidity, could not be formed in these preparations due to the absence of fairly large ZrO₂ domains.     

Structure of polyurethane spinning solutions and its effect on properties of spandex fibre

Conclusions The supermolecular structure of solutions of polyurethane and of polytetramethylene ether glycol has been studied. It has been found that spinning solutions having a large content of gel-particles are obtained from a more structurized polytetramethylene ether glycol.Correlation analysis of the dependences of physico-mechanical fibre indices on parameters of the low-molecular compounds of spinning solutions has shown that the specific load and load at 300% extension vary directly proportionally to the concentration and inversely proportionally to the size of particles in the spinning solution, and shrinkage in hot water varies in the opposite way.Translated from Khimicheskie Volokna, No. 1, pp. 37–38, January–February, 1989.     

Generalized analytical expressions for Tafel slope,reaction order and a.c. impedance for the hydrogen evolution reaction (HER): mechanism of HER on platinum in alkaline media

Following the generally accepted mechanism of the HER involving the initial proton discharge step to form the adsorbed hydrogen intermediate, which is desorbed either chemically or electrochemically, generalized expressions for the Tafel slope, reaction order and the a.c. impedance for the hydrogen evolution reaction are derived using the steady-state approach, taking into account the forward and backward rates of the three constituent paths and the lateral interactions between the chemisorbed intermediates. Limiting relationships for the Tafel slope and the reaction order, previously published, are deduced from these general equations as special cases. These relationships, used to decipher the mechanistic aspects by examining the kinetic data for the HER on platinum in alkaline media, showed that the experimental observations can be consistently rationalized by the discharge-electrochemical desorption mechanism, the rate of the discharge step being retarded on inactive platinum compared to the same on active platinum.Nomenclature C _d double-layer capacity (µF cm^–2) - E _rev reversible electrode potential (V) - F Faraday number (96 487 C mol^–1 ) - R gas constant - T temperature (K) - Y _f Faradaic admittance (^–1 cm^–2) - Y _t Total admittance (^–1 cm^–2) - Z _f Faradaic impedance ( cm²) - i _f total current density (A cm^–2) - i _nf nonfaradaic current density (A cm^–2) - j - k ₀ ¹ rate constant of the steps described in Equations 1 to 3 (mol cm^–2 s^–1 ) - j - qmax saturation charge (µC cm^–2) - Laplace transformed expressions for i, and E - _{1 3} symmetry factors for the Equations 1 and 3 - saturation value of adsorbed intermediates (mol cm^–2) - overpotential - coverage by adsorbed intermediates - angular frequency This paper is dedicated to Professor Brian E. Conway on the occasion of his 65th birthday, and in recognition of his outstanding contribution to electrochemistry.     

Pheromone biosynthesis in lepidoptera

Pheromone components for many lepidopteran species are produced by the use of unique chain-shortening and 9, 10, and 11 desaturase systems. Correlations in the Tortricidae indicate that the pheromone components derived from 9 and 01 desaturases are found in the more primitive species (those possessing morphological plesiomorphies). The precise blend ofZ andE acetates in a number of species is regulated in the final reduction sequence from acyl intermediates. Preliminary research has been conducted on the characterization of the various desaturase enzymes used and on the important blend regulating sequence. Initial purification work on the 11 desaturase enzyme found in the cabbage looper moth is reported.     

Connection between the supermolecular structure of viscose with characteristics of the cellulose and with the properties of fibres and films obtained

Conclusions -- The supermolecular structure of spinning solutions from viscose manufacturing operations in the Balakovskii Khimvolokno PO has been studied by the turbidity spectrum method.-- Multiple and paired correlation equations have been obtained for the parameters of viscose supermolecular structure and the characteristics of the cellulose and the physicomechanical characteristics of hydrocellulose fibres and films.Translated from Khimicheskie Volokna, No. 5, pp. 42–45, September–October, 1991.     

Synergistic Sex Pheromone Components of White-Spotted Tussock Moth, Orgyia thyellina

In 1996, the exotic white-spotted tussock moth (WSTM), Orgyia thyellina (Lepidoptera: Lymantriidae), was discovered in Auckland, New Zealand. Because establishment of WSTM would threaten New Zealand's orchard industry and international trade, eradication of WSTM with microbial insecticide was initiated. To monitor and complement eradication of WSTM by capture of male moths in pheromone-baited traps, pheromone components of female WSTM needed to be identified. Coupled gas chromatographic–electroantennographic detection analysis of pheromone gland extract revealed several compounds that elicited responses from male moth antennae. Mass spectra of the two most EAD-active compounds suggested, and comparative GC-MS of authentic standards confirmed, that they were (Z)-6-heneicosen-11-one (Z6–11-one) and (Z)-6-heneicosen-9-one, the latter termed here thyellinone. In field experiments in Japan, Z6–11-one plus thyellinone at a 100:5 ratio attracted WSTM males, whereas either ketone alone failed to attract a single male moth. Addition of further candidate pheromone components did not enhance attractiveness of the binary blend. Through the 1997–1998 summer, 45,000 commercial trap lures baited with 2000 g of Z6–11-one and 100 g of thyellinone were deployed in Auckland towards eradication of the residual WSTM population.Dedicated to my dear mother in honor of her 75th birthday     

Effect of carbon disulfide consumption on the basic properties of viscose prepared from radiation-modified cellulose

Conclusions -- The process of preparing viscose from radiation-modified cellulose using carbon disulfide in the range of 6–32% of the weight of -cellulose in the xanthation has been investigated.-- Equations have been given which describe the dependence of the degree of esterification of the cellulose xanthate, the ripeness index, the byproduct content, the viscosity, and the filterability of the viscoses on CS₂ consumption in xanthation within the range 6–32% by wt.-- It has been found that a decrease in consumption of CS₂ primarily affects the viscosity of the viscoses obtained, and then it affects figures which characterize the content of byproducts, degree of esterification of the cellulose xanthate, ripeness, and the filterability of the spinning solutions.Translated from Khimicheskie Volokna, No. 5, pp. 51–53, September–October, 1991.     

Relationship between the solubility of water vapour in caprolactam and its partial pressure and temperature

Conclusions It has been shown that the solubility of water vapour in a caprolactam melt decreases sharply with an increase in temperature, and also in the presence of acetic acid and a protective gas. Therefore, to increase the concentration of water in a caprolactam melt it is advantageous to use non-volatile molecular weight regulators and water vapour as the protective gas in the first section of a continuous polymerization tube.First communication in a series Investigation into the chemistry and technology of polycaproamide.Ivanov Chemical Technology Institute. Translated from Khimicheskie Volokna, No. 3, pp. 7–9, May–June, 1969.     

Available nitrogen in soils and its determination by the ‘Nmin-method’ and by electroultrafiltration (EUF)

Excess nitrogen fertilizer rates are an environmental hazard. To avoid excess rates, the level of available nitrogen in the soil must be known and considered for assessing the nitrogen fertilizer rate. In arable soils nitrate and exchangeable ammonium in the rooting depth of a crop are directly available to plant roots. These two nitrogen forms are recovered with the Nmin method and they are considered in assessing the nitrogen fertilizer rate for arable crops.Besides nitrate and ammonium recovered by the Nmin method from soil samples taken in early spring, a considerable amount of organic soil nitrogen may be mineralized during the growth period and contribute to crop nutrition. The nitrogen mineralization potential can be determined in incubation tests. The absolute quantities of mineralized nitrogen thus obtained, however, are much higher than the mineralization rates under field conditions. It is for this reason that incubation tests have not obtained a major importance for assessing nitrogen fertilizer rates.With the electro-ultrafiltration (EUF) method nitrate, ammonium, and a minor portion of organic soil nitrogen are extracted from a soil suspension. There is experimental evidence that this organic nitrogen (=Norg) is easily mineralizable. Based on field experiments with cereals and maize formulae were established by which the nitrogen fertilizer rate can be calculated. In these formulae nitrate, ammonium and organic nitrogen extracted by EUF are considered.Advantages and drawbacks of the Nmin method and EUF method are discussed.     

On the Charge Carrier Concentration in Sodium–Calcium Aluminophosphate Glasses

The dc and ac conductivities of the xNa₂O–(35 – x)CaO–7.5Al₂O₃–57.5P₂O₅glasses (mol %) with x= 0–35 are studied in the frequency range from 20 Hz to 1 MHz at different temperatures. It is found that the dc conductivity strongly depends on xonly for glasses with x 10. For glasses with x 5, the dc conductivity is virtually composition independent. The dependence of the ac conductivity plotted on the log(()/_dc) vs. log(/_dc) coordinates is analyzed. The ac conductivity represented in these coordinates depends on xonly for glasses with x 5, in which the dc conductivity does not depend on x. For glasses with xin the range from 10 to 35, all the isotherms of the ac conductivity closely coincide with each other. This result is discussed in the framework of two hypotheses: (1) the conductivity () is determined by the dynamic polarization (of the Maxwell–Wagner type at low frequencies) of the material due to spatial fluctuations of the density of paths providing the migration of sodium ions and (2) the concentration of charge carriers is independent of x.