Vol 48, No 2 (2016)

Rheological studies of wet-spinning of fibers were carried out. A solution (18%) of acrylonitrile (60%) and vinylchloride (40%, SKhN-60) in DMF was used. The main rheological characteristics of fiber-jet tension were the apparent longitudinal viscosity and the fiber structuring time; the shear characteristics, the complex (Newtonian) viscosity and equilibrium relaxation time. An attempt was made to relate these rheological tensile and shear characteristics to each other. Two methods were used to calculate the longitudinal viscosity. The first used the segment structuring time (length) to calculate the tensile strains and; correspondingly, the longitudinal viscosity. The apparent viscosity was λ_a = 1.2.105 Pa.s for a spinning solution Newtonian viscosity of 5.15 Pa.s and spinneret extrusion of unity. This was approximately equal to values for spinning solutions that were obtained by other researchers. The second method was used for the first time to determine the longitudinal viscosity. The equilibrium relaxation time was used to calculate tensile strains and; correspondingly, the longitudinal viscosity. The obtained longitudinal viscosity was called the equilibrium value (6.81 Pa.s). Equations determining the length of the structured fiber-jet segment were obtained theoretically and validated in practice.

X-ray diffraction analysis shows that in complex polypropylene filaments (CPF) modified with lowdensity polyethylene (LDPE) the latter is present as a single anisotropic phase. It has been proven that LDPE promotes further crystallization of polypropylene (PP) in the production of CPF due, apparently, to the mutual influence of the PP chains and LDPE within the amorphous phase providing increased segmental mobility of the molecules and the additional formation of small crystallites of PP, in particular, in the transition from lamellar sheet structure to fibrillar formations of stretched chains during orientational drawing. The PP crystallization effect manifests to the maximum extent at low concentrations of LDPE in CPF – 0.5-7.5 wt. %. Introduction of high density polyethylene (HDPE) into CPF to a lesser extent promotes crystallization of PP in comparison with LDPE, which can be due to structural features of the crystalline phases of polyethylene present in the fibers determining their different effect on the mobility of macromolecules in the matrix of fibers and, consequently, the crystallization of polypropylene during thermal drawing of the fibers.

Methods of capillary viscometry, spectroscopy, and conductometry were used to investigate the compatibility of components in a biopolymer composite made of polyvinyl alcohol, products of enzymethermal degradation of collagen, and maltodextrin in aqueous solutions. The optimum proportion of maltodextrin ensuring high physicomechanical properties of biopolymer films was determined.

The optimal parameters for modifying polyacrylonitrile (PAN) fiber to produce flame-resistant materials were established from kinetic absorption studies of the flame-retardant system components and the combustion indexes of the modified fibers. The absorption parameters were determined. The absorption of the flame-retardant systems by PAN fibers obeyed the Freundlich equation for the non-linear dependences of the flame-retardant concentrations on the fibers as a function of their bath concentrations.

The results of experimental determination of rigidity of glass, carbon, and organic yarns are reported. It is shown that glass yarn, from which triaxial Armaton TKh 700 fabric is made, has the highest coefficient of rigidity and organic yarn, from which SHM fabric is made, has the lowest coefficient of rigidity. The rigidity coefficients of EE380 and EE106 fabrics, which are very close in glass fibre composition, differ by more than 70%. All glass fibres are close to each other in expansion angle values. Expansion angle of carbon fibres is smaller than that of glass fibres, and organic fibres have the smallest expansion angles, which indicate that the latter are least creasy.

The antiseptic properties of a cotton linen set modified with silver hydrosol were investigated. The biocidal, bactericidal, and bacteriostatic stability of the modified materials to moist treatments was determined.

Graphs of the time dependence of the kinetic parameters for the process of drying are obtained by analyzing experimental data on the drying of linen fabric with a surface density of 240 g/m². A new design is proposed for the heating system of a drum-type drying machine and includes a channel system to deliver steam to the drying drums. The possibility of grouping the drums into blocks inside a certain steam group is discussed.

from a study of the adsorption of the cationic surfactant (SA) catamine AB from aqueous solutions onto the surface of polyester fibers are reported. It was found that a bimolecular layer was formed after adsorption of this SA. The SA molecules in the first adsorbed layer reacted with polyester polar groups to form an interpolymer complex. A specific adsorption potential, i.e., intermolecular interaction of SA hydrocarbon groups with fiber hydrophobic sections, was also apparent. The second adsorption layer was formed exclusively via reaction of hydrocarbon radicals of the first and second adsorbed layers. The effect of catamine-AB adsorption on the polyester-fiber electrokinetic surface potential was investigated. It was found that the negative electrokinetic potential decreased as the adsorbed SA layer formed on the fiber surface. The isoelectric surface state was observed at a catamine concentration of ~5·10^–2 g/L, after which the fiber became overcharged. This indicated that the SA adsorbed to form a bilayer structure.

The binding coordinates of carbon-fiber diagnostic sensors were determined experimentally. Stress—strain states of constructions to be diagnosed using carbon fibers and a finite-element method were presented.

This article examines how the distribution of the total gear ratio among the stages of a lever-rod transmission affects the force in the drive of the mechanism. It is shown that a uniform distribution of the ratio among the stages does not ensure the lowest possible value for the total corrected moment of inertia in the drive.