Preparation of polyamide fibres from liquid-crystal solutions of mixtures of rigid- and flexible-chain polymers

Conclusions The process of preparing heat-resistant polyamide fibres from a mixture of stiff-chain copolyamides and the flexible-chain polycaproamide, and properties of these fibres, have been investigated.It has been shown that the behavior of the mixtures is caused to a considerable extent by the chemical structure of the copolyamides.Composite fibres have been prepared having a low density, which are recommended for the development of new light thermally insulating materials.Translated from Khimicheskie Volokna, No. 6, pp. 31–32, November–December, 1988.     

Structural features and properties of composite and ultrathin fibres from melts of polymer mixtures

Kiev Technological Institute of Ligh Industry. Translated from Khimicheskie Volokna, No. 3, pp. 45–47, May–June, 1992.     

Matrix-fibrillar fibres from mixtures of thermodynamically compatible polymers

Conclusions The mechanisms of formation of a matrix-fibrillar fibre structure from melts of mixtures of thermodynamically compatible polymers on application of a mechanical field have been studied:a mechanism which is inherent to thermodynamically incompatible polymers (for melts of potentially mutually soluble polymers which are nonuniform in composition);the jet-fibre transition, which can be effected by a nucleation or spinodal mechanism in the amorphous separation of a homogeneous system, or as a crystallization separation on application of a mechanical field to the system.Translated from Khimicheskie Volokna, No. 2, pp. 51–53, March–April, 1985.     

Limiting value of the elastic modulus of composite fibres based on flexible-chain polymers

Conclusions It has been shown theoretically that the elastic modulus of model composite fibres which are matrices of a flexible-chain polymer filler with fibrils of an ultra-high-modulus polymer can have values which exceed the elastic modulus of the fibrillar crystallite.The author expresses his thanks to V. A. Smirnova and V. I. Grishchenko for performinig the necessary calculations.Translated from Khimicheskie Volokna, No. 3, pp. 12–15, May–June, 1987.     

Water vapor sorption and structural features of mixed fibres from rigid-chain copolymers

Conclusions Sorption isotherms for vapors of an active and an inactive sorbate have been measured for fibres prepared from mixtures of two rigid-chain copolyamides.It has been shown that the investigated mixed fibres have low specific surface values (with respect to the inert sorbate). The experimental values of water vapor sorption for these are less than those calculated by an additive scheme, the greatest decrease being observed at a content of 10% by wt. of the second rigid-chain component (CA) in the mixture.Ideas about interpolymer interactions which are displayed in extreme form at a definite composition of the mixed fibre (at a CA content of 10%) have been proposed to explain the nonadditive change in water vapor sorption by the mixed fibres.Translated from Khimicheskie Volokna, No. 1, pp. 11–13, January–February, 1989.     

Some features of the process of strengthening fibres from fluorine-containing polymers

Conclusions An anomaly in mechanical properties in spinning F2M fluorinated copolymer has been detected.The reason for preference for using a multistage scheme for strengthening fluoropolymers has been analyzed.Translated from Khimicheskie Volokna, No. 1, pp. 31–32, January–February, 1990.     

Structural features and strength of carbon fibres

Conclusions -- Dimensions, orientation of the ordered regions, and also the heterogeneous structure parameters have been determined for a number of foreign and domestic high-strength and high-modulus carbon fibres (CF). Characteristic features of the behavior of the heterogeneous structure of CF with change in dimensions of the ordered regions have been noted.-- It has been shown that small dimensions of the ordered and unordered regions are characteristic of high-strength CF together with an increased mean density of the unordered and porous phases.-- An attempt has been made to establish correlations between the ultimate strength of CF in extension and the heterogeneous structure parameters of the fibre.Translated from Khimicheskie Volokna, No. 1, pp. 47–49, January–February, 1991.     

Structural features and properties of fibres based on mixtures of an ethylene-vinylacetate copolymer with a copolyamide

Conclusions By x-ray analysis, we have confirmed the previously expressed hypothesis of a forced deformation of SÉVA on flow of an SÉVA—SPA mixture as a result of specific interaction of the components at the interface: the degree of orientation of the SÉVA macromolecules in the microfibres is higher than in a monofilament from the starting polymer.It has been shown that ultrathin SÉVA fibres are characterized by a porosity, caused by micro- and macro-hollows, which causes a decrease in their strength as compared with the strength of ordinary SÉVA fibres.Kiev Technological Institute for Light Industry. Translated from Khimicheskie Volokna, No. 2, pp. 39–41, March–April, 1992.