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Publications (64)
Experimental X-ray diffraction analysis procedures and calculation algorithms are proposed for determining the degree of crystallinity of flax fibres of varied purity and their cellulose component from the integral values of diffraction by the crystallite regions of the analysis sample and the reference standard, which are normalized, taking accoun...
Constructing phase diagrams for the mixtures of semicrystalline polymers and low molecular mass substances by DSC can meet with difficulties in the case of slow polymer crystallization. A problem of this kind is encountered for high-energy compositions poly[3,3-bis(azidomethyl)oxetane] (PBAMO)–2,4-dinitro-2,4-diazapentane (DNAP). In this study, the...
The influence of the spinneret draw ratio and subsequent solid-state stretching of polypropylene multifilament yarns (PMY) on changes in the orientation of crystallites and molecular chains in the polymer amorphous regions was studied using x-ray structure analysis. It was shown that crystallites and molecular chains of amorphous polypropylene (PP)...
The comparative research of composition and supramolecular structure of the flax fibers received by methods of a cottonization and a mechanical elementarization under the influence of the cyclic deforming loadings was conducted. It was shown that under the influence of cyclic loadings removal of a considerable part of impurity with the increase in...
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 LD...
The need to take into account the anisotropy of compact samples pressed from grinded
polypropylene (PP) fibres at a determination of the degree of polymer crystallinity by X-ray method was shown. It was proved that the breach of the spherical scattering symmetry of X-rays by PP
fiber samples is not connected with an amorphous phase of polymer. The...
The molecular-disperse distribution of tetraphenylporphine in solution-cast cellulose triacetate and diacetate films was established by X-ray structural analysis. It was shown that the low crystallizability during heat treatment is a characteristic feature of cellulose acetates membranes containing tetraphenylporphine. This could be due to fact tha...
A melting temperature of 90.4°C (complete amorphization) for macromolecular poly-3,3-bis(azidomethyl)oxetane is determined via the hydrostatic-weighing method. This value corresponds to the end of the endothermic peak of the DSC thermogram and is ~10°C higher than the maximum value. The amorphization of the polymer is found to proceed mainly owing...
The need to account for the anisotropy of compact samples pressed from ground polypropylene (PP) fibers was demonstrated during a determination of the degree of polymer crystallinity using x-ray structure analysis. The destruction of the spherical scattering symmetry of x-rays by PP fiber samples was proven to be unrelated to the polymer amorphous...
The degrees of crystallinity of powdered CTA and CDA that were calculated from x-ray crystal structure analysis (XSA) data were 27.9% and 6.7%, respectively. It was found that anisotropic placement of structural elements in cellulose acetate membranes destroyed the spherical scattering symmetry and hindered determination of the degree of crystallin...
We show that for orientational drawing of polypropylene multifilament yarns within the draw ratio range 4.2-5.6 at elevated temperature, we observe practically complete transition of the folded-chain lamellar crystallites to fibrillar crystallite formations of stretched chains, resulting in a significant increase in the relative breaking load for t...
We have developed a procedure for quantitative analysis of small-angle x-ray scattering by cellulose fibers swollen in water, enabling a comparative estimate of the interfacial surface area between the crystalline and amorphous phases and also the specific surface area of the crystallites. We show that the specific interfacial surface area between...
The effects of narrowly and widely dispersed fractions of ultradispersed polytetrafluoroethylene on the structures of melt-spun polypropylene fibrous materials and the ultimate tensile half-cycle characteristics of polypropylene filaments and nonwoven materials have been studied via X-ray diffraction analysis, optical microscopy, and differential s...
An x-ray structure analysis found that increasing the apparent jet spinning of polypropylene complex threads (PCT) from 1400 to 16,300% had practically no effect on the orientation of polymer crystallites but decreased substantially the ability to form a*-oriented packed lamellae in which the molecular chains were perpendicular to the thread axes....
An x-ray structure analysis found that increasing the apparent jet spinning of polypropylene complex
threads (PCT) from 1400 to 16,300% had practically no effect on the orientation of polymer crystallites
but decreased substantially the ability to form a*-oriented packed lamellae in which the molecular
chains were perpendicular to the thread axes....
We describe a technique for analysis of the specific internal surface area (SISA) of dry cellulose fibers by small-angle x-ray scattering, making it possible to rapidly evaluate the change in the polymer matrix — microvoid interface for cellulose-based materials when exposed to modifying factors. We demonstrate that treatment of cotton fibers with...
New approaches to the development of a biochemical pretreatment process, leading to an improvement of the finishing technology through its unification, are formulated. Evidence is provided that the multidirectional selective action of enzymes in complex lignin-containing polysaccharides promotes efficient delignification processes. New simplified,...
Hydrostatic weighing of a polymer in an immersion liquid using low-density polyethylene as an example was used to show that a condition for the lack of recrystallization of partially crystalline polymers upon annealing is the attainment at this temperature of thermomechanical equilibrium that determines the ratio of the amounts of macromolecule ele...
A description is given of a special holder for the x-ray diffractometric analysis of oriented fibers. Use of the holder makes it possible to obtain flat compact specimens and, when slit collimation is used, keeps the conditions for the scattering of radiation by the specimens constant as the fibers rotate about the horizontal axis. The article disc...
Biodegradation of flax fibers differing in the chemical composition, structure of cellulose, and content of concomitant natural
impurities (pectin compounds, lignin, hemicellulose) was studied. The effect exerted on the biodegradation by silver nanoparticles
immobilized in the fiber was evaluated.
Substituted formyl azobenzenes are effective light and thermal stabilizers of polyethylene even in concentrations 20 times
lower than for industrial stabilizers. X-ray structural analysis showed that the presence of mesogens in the LDPE matrix prevents
crystallization of the polymer as a result of exposure to light and heat, preserving the strength...
Comparative analysis of the characteristics of supramolecular structures of dry and swollen cotton fibers makes it possible
to differentiate structural regions accessible to water. The revealed features of water desorption from cotton cellulose (exceptionally
low rates at the final stages, presence of residual moisture) are related to the removal o...
The molecularly disperse distribution of tetraphenylporphine (TPP) in cellulose triacetate (CTA) films fabricated from solution
was established by x-ray structural analysis. It was shown that low crystallizability during heat treatment is a characteristic
feature of CTA membranes containing TPP. This could be due to the position of the porphyrin mo...
It was shown that in treating PET fibre materials with a solution of ultradisperse, low-molecular-weight polytetrafluoroethylene
in supercritical carbon dioxide, an ultrathin layer of fluoropolymer that gives the fabric a high degree of water repellency
is formed on the surface.
The effect of heat treatment of Armos fibre in different conditions on the supramolecular structure of the polymer was investigated
by x-ray structural analysis. The analysis of the physicomechanical indexes of fibres treated with heat in different conditions
showed that it was more effective in the presence of superheated steam. It was found that...
Abstract The important dependence of the x-ray diffraction parameters of cotton fibres on the compacting conditions and type of material in production of compact preparations was demonstrated. The method of determining the polymorphous composition of cellulose in the crystallite regions of cotton fibres for anisotropic materials was substantiated....
It was shown that in going from the mesomorphic γ-modification of PA-6 to the stable α-form, formation of intermediate structures
can play an important role. It was found that the formation of the polymorphous α-modification in conditions of heat treatment
at 180°C takes place due to the amorphous regions of the polymer.
It was found that the structure of cotton fabrics restricts swelling of the fibres required for spinning alkaline cellulose
and polymorphous conversion of the polymer in treatment with sodium hydroxide solutions. The necessity of individually selecting
the concentration conditions of mercerization for fabrics of different structure for the optimum...
It is shown that the important change in the x-ray diffraction parameters in preparation of compact products from microcrystalline cellulose and ground cotton fibres by pressing is not due to the amorphous phase of cellulose. A method for determining the degree of crystallinity of cellulose in anisotropic materials using an external standard that e...
X-ray structural analysis showed that both the crystallite content and the degree of perfection of their surface layer increase during dampening of cotton cellulose. The maximum structural ordering of cellulose is attained at a fibre moisture content 14.8%. The determining role of the absorption mechanism of dissolution of water in amorphous region...
For dry and moistened cotton fibers, diffuse components of coherent X-ray scattering are resolved and quantitatively estimated using various methodical procedures for sample preparation, measurements, and processing of experimental data. The changes in the diffraction patterns of diffuse X-ray scattering were found to be different below and above t...
Alteration of the crystal structure of cotton fibers during their absorption of water vapor at 293 K over the entire 0-100% range of relative air humidity was quantitatively studied using the X-ray diffraction technique. It was shown that the ordering of cotton cellulose as a function of the moisture content is nonmonotonic in character, which is d...
Swelling of the aramid fibres Kevlar, Armos, SVM, and VMN in dimethylformamide at 298 K is accompanied by an increase in the proportion of ordered regions inaccessible to liquids and a decrease in the molecular orientation in accessible, less ordered regions of the polymer. Addition of small amounts of a thermodynamically active liquid to a solutio...
A specific change in the initial modulus of elasticity and stress relaxation is the most important consequence of the structural
reorganizations of the aramid fibres Armos, VMN, and SVM caused by dissolution of acetone and ethanol in the bulk of the polymer.
Thermodynamic parameters of dissolution of n-alcohols (C1-C4), isobutyl alcohol, acetone, aceto-nitrile, and isoamyl alcohol in amorphous strictures of cellulose esters were studied by the reversed-phase gas chromatography. It was shown that the sorption of low-molecular-mass substances in cellulose trifluoroacetate occurs mainly in the cavities be...
The caustic-soda mercerizing of cotton fabrics with 14-23% aqueous solutions at 20°C for 20 sec is studied. During this interval cellulose I is converted into cellulose II. The results are used to construct an algorithm for optimizing the alkali concentration to improve the strength and lustre of bleached cotton fabrics in different weaves.
It was shown that acetone and ethanol dissolved in aramid fibres at the level of 2–8 vol. % cause alterations in the fine
structure of these fibres. The direction and degree of the changes in the structure of the fibres are a function of the features
of the molecular structure of the polymer.
The fine structure of the aramid fibres Armos, SVM, and VMN was investigated by x-ray diffraction. It was found that the fine
structure of Armos, SVM, and VMN fibres is characterized by rigorous longitudinal ordering due to simultaneous shifting of
the neighboring macromolecules and the formation of unusual layers as a result. A new methodological...
The presence of ranges of concentration changes in sodium hydroxide solutions has been detected where sudden increases occur in the breaking strength of cotton fabrics and yarns during mercerizing. The dependence of these concentration boundaries on the type of material processed is shown. Mercerizingsolutions, the concentration of which ensures a...
It is shown that the washing of cotton fabrics with water containing up to 10-20% sodium hydroxide after mercerizing reduces the fibre diameter whilst ensuring that the cellulose remains in the plasticized condition. A method for stabilizing the dimensions of the fabrics whilst processing them on chain mercerizing lines is described which reduces b...
A study shows that, when cotton fabrics are processed with 15-21% solutions of sodium hydroxide, only 30-40% of the fabric shrinkage is caused by a reduction in yarn length. Mathematical modelling is used to show that the reduction in yarn diameter during fabric extension in the course of mercerizing considerably facilitates the stretching of texti...
It is shown that there is a need to forecast the limit concentrations of sodium hydroxide to ensure the specified level of structural modification in rapid mercerizing (20sec) of scoured cotton fabrics having different constructions and weights.
The effect of microwave radiation on the fibre structure and properties of cotton fabrics is considered. Treatment up to 10 min does not reduce the fabric strength; a further increase in treatment time sharply degrades the cellulose. The degree of crystallinity of the cotton cellulose is not altered. The effect of microwave treatment on porosity is...
Studies of caustic-soda mercerizing of cotton fabrics show that the level of structural modification of fibres which increases the sorption properties depends solely on the volume characteristics of the material. There is a critical inverse volumetric mass value for scoured and bleached cotton fabrics above which the structure does not affect the c...
The linear relationship between the content of structural modifications of cellulose in cotton fibres and the standardized intensity of X-ray diffraction reflexes is noted. Equations based on X-ray diffraction reflex intensity for modified fibres and for initial and mercerized fibres as standards have been used to calculate the content of structura...
The effect of thermal and azeotropic methods of dye fixing on the structural changes and relaxation processes in polyester fibres is studied by X-ray analysis on samples taken from yarns and fabrics. It is shown that azeotropic mixtures of benzyl alcohol and water, which plasticize the polyester fibre, relax the internal stresses without appreciabl...
The effect of fabric tension on structural modifications in the caustic-soda mercerizing of woven cotton fabrics is investigated. Rapid and slow conversion of cellulose I to cellulose II during mercerizing under tensionless and tensioned conditions is reported. The reasons for the insignificant effect of the processing conditions on rapid mercerizi...
A method, applicable to any cellulosic fibre regardless of polymer modification, based on determination of integral scattering with the aid of a computerized diffractometer, has been developed. Its use for normalizing the X-ray scattering power of cotton and rayon fibres is described.
The effect of swelling agent concentration on structural changes in the cellulose during the caustic-soda mercerizing of cotton fabrics is discussed on the basis of the barium activity number.
A 20% sodium hydroxide solution was found to have a plasticizing effect on cotton fabric treated at 100 degrees C, resulting in uniform impregnation. After treatment the fabric was cooled with water to bring about a transition of cellulose I to cellulose II similar to the amount converted by heating at 100 degrees C. Even impregnation in the fixed...
The constructions of woven cotton fabrics are examined in relation to the effects produced during caustic-soda mercerizing. With an increase in the mercerizing time, the cellulose II content of the fibres tends towards an equilibrium value which depends considerably on the fabric construction; the basic modification of the polymer occurs at the rap...
X-ray analysis was carried out on initial bleached cotton fabric after treatment with sodium hydroxide or liquid ammonia in order to determine the extent of the polymorphic modification content of cellulose in fibres. By treating the fibres with liquid ammonia, a complete conversion of initial cellulose to cellulose III was achieved, giving fibres...
The structural and physical/chemical changes in flax fibres caused by liquid-ammonia mercerizing are investigated by X-ray analysis and infrared spectroscopy. The fibre structure does not have a significant effect on liquid-ammonia penetration. Results indicate that processing with liquid ammonia improves the physical/chemical characteristics of th...
The transition was accompanied by a reduction in the transverse size of the crystallites, the appearance of regions with fairly high orientation of the chains along the fibre axis but low orientation in the perpendicular direction, and longitudinal shift in the alignment of the chains. These changes are explained by precrystallite region formation.
