Physicomechanical and spectral properties of modified fibre-forming polycaproamide

Conclusions The physicomechanical characteristics of fibre based on polycaproamide which has been modified at the synthesis stage with 1–5% by wt. of sodium 4,4-diaminostilbene-2,2-disulfonic acid have been investigated.Spectral-luminescent properties of solutions and films of the modified polycaproamide have been described.An evaluation of the ability of two types of dye to dye the modified polycaproamide fibres has been carried out, and it has been found that the introduction of diaminostilbene fragments helps raise the dyeability of the fibres with basic cationic golden-yellow 2K.Translated from Khimicheskie Volokna, No. 6, pp. 38–39, November–December, 1987.     

Deformation properties of modified polyacrylonitrile fibres

Conclusions Deformation properties of polyacrylonitrile fibres modified with alkali metal salts have been studied.The introduction of alkali metals by treatment of freshly spun gel-fibre with solutions of the appropriate salts aids in loosening fibre structure.Both the form of cation and also of the anion in the salt introduced affect the deformability of the modified fibres.Translated from Khimicheskie Volokna, No. 4, pp. 40–41, July–August, 1989.     

Some properties of modified polyacrylonitrile fibres

Fibre-forming copolymers of acrylonitrile and a monomeric quaternary ammonium salt, β-methacryloylhydroxyethyl-(N-dimethyl,methylene)ammonium iodide, were obtained by wet spinning and their physicomechanical and structural properties were investigated. It was found that the modified fibres have a set of valuable properties in comparison to the industrial fibre Nitron.     

Spontaneous elongation of acetate fibres in dimethyl sulfoxide vapors: dynamics, structure, energetics

The effect of a spontaneous change in the size (elongation-partial retraction) of di- and triacetate fibres in DMSO vapors in the 19–60°C range, accompanied by initiation of orientation events in the polymer matrix was detected. Sorption of DMSO vapors by the polymer in self-deformation of the acetate fibre does not obey Fick’s law and is described by extremal swelling curves that indicate the multistage character of the reaction of the sorbate vapors with the polymer. The energetics of spontaneous elongation of cellulose acetate in DMSO vapors was investigated, and the specific work of self-deformation and “negative” longitudinal viscosity were determined. The values of the specific heat was typical of transitions from the isotropic to the LC state. It was found that the stereomeric structure of the polysaccharide changes during a cyclic change in the size of the fibre, confirmed by inversion of the specific optical rotation sign. The data obtained can be described in terms of phase and conformational transitions and the mechanism of reaction of the polymer with the solvent vapors forming the LC phase with it. Translated from Khimicheskie Volokna, No. 5, pp. 38–44, September–October, 2008.     

Physicomechanical properties of filled natural rubber vulcanizates modified with phosphorylated cashew nut shell liquid

Effect of fillers like carbon black, silica, and china clay on the cure characteristics and physicomechanical properties of natural rubber (NR) modified with phosphorylated cashew nut shell liquid (PCNSL) in various proportions has been studied. Prominent cure retardation has been observed with progressive increase in concentration of PCNSL from 0 to 20 phr. The softening effect of PCNSL on the vulcanizate has been displayed by the linear decrease in hardness and tensile modulus and the increase in elongation at break with the increase in concentration of PCNSL. The results on the tensile and tear strengths of the vulcanizates showed that the reinforcing effect of the fillers were maximized at concentrations of PCNSL ranging from 5 to 10 phr. Also, the PCNSL-modified NR vulcanizates showed improved resistance to thermo-oxidative ageing and decomposition, especially at the higher concentration of 20 phr. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1303–1311, 1998     

Magnetic properties of PAN-based carbon fibres modified with magnetite nanoparticles

The magnetic properties of PAN-based carbon fibres modified with magnetite nanoparticles are presented and analyzed. PAN fibres and PAN-based carbon fibres modified with different amounts of magnetite are characterized by the use of magnetization measurements and Mössbauer spectroscopy techniques. The investigations revealed that magnetite (Fe₃O₄) decomposed into Fe_α, Fe_γ and cementite (Fe₃C). Precise analysis of the phase’s contents for different carbon fibres has been carried out in relation to the initial magnetite compound. Analysis of the Mössbauer spectra allowed the determination of the phase contents in fibres with different initial magnetite concentrations. Partial transformation of magnetite into γ-Fe induces catalytic carbonization and formation of a highly crystalline carbon matrix at 1000 °C. The apparent crystallite size in carbon fibres containing 30% magnetite was almost seven times higher than that found in the pure carbon fibres.     

Improving the physicomechanical properties of acetate fibres and films

Conclusions It is possible to modify acetate fibres during the spinning process by adding crosslinking agents (dimethylolethyleneurea or dimethyloldihydroxyethylurea) to the spinning solution with subsequent heat-treatment of the fibre.The modified fibres have improved elastic properties (crease resistance, resistance to double bending) while preserving their strength characteristics.Deceased.Translated from Khimicheskie Volokna, No. 1, pp. 38–40, January–February, 1983.