Variant for Prediction of Deformation of Synthetic Fibres

A new function with certain advantages over the previously used functions is proposed for use as the integral relaxation kernel for predicting the stress—strain states of synthetic fibres and other textiles by calculation in the region of nondestructive loads using an indicial equation. The range of prediction of the viscoelastic properties was expanded and the working equations were simplified. Correction of the calculation of the viscoelastic properties with the points on the experimental stress—strain diagram will allow increasing the reliability of prediction of deformed states.     

Effect of the Level of Preliminary Deformation on the Stiffness of Synthetic Fibres

The deformation stiffness of synthetic fibres increases significantly (by 3 and more times) as a result of preliminary stretching. The stress—strain diagram of the initial synthetic fibre can be used to predict the character of the change in the deformation stiffness in different stages of preliminary elongation. In the stretching segments where destructive processes are weakly manifested, the stiffness of the stretched fibres increases with an increase in the deformation. In the region of intensive molecular destruction processes, the deformation stiffness of the stretched fibres almost does not change, which is due to overlap of competing processes: structure ordering and molecular chain breaking.     

Dynamic Relaxation of Synthetic Fibres

The stress regions where amplitude-modulated oscillations (AMO) appear, intensify, weaken, and disappear were determined for PET, Armos, SVM, Terlon synthetic fibres and monofilament PET fibres. The reappearance of AMO caused by the structure of the random copolymer was also found in Armos synthetic fibre. It was found for all fibres investigated that AMO do not appear at temperatures close to the glass transition temperature or any other “softening” point. A method is proposed for determining the temperature after which AMO do not appear. AMO were also not observed in many synthetic fibres (for example, polypropylene, polyethylene) in the devitrified state. The various explanations of AMO with respect to the structural and kinetic features of oriented polymers, related to the inhomogeneity of the supramolecular structure of oriented polymers, combined with the activating effect of an external load on the relaxation spectrum are examined. __________ Translated from Khimicheskie Volokna, No. 4, pp. 44–46, July–August, 2005.     

Sewing Threads of Cotton and Synthetic Fibres

A comprehensive series of mono- and di-substituted derivatives of Brilliant Green has been prepared and the various electronic absorption spectra have been determined. Substituents in the 3- or 4-position have little effect on the intensity of the first band, but the wavelength of maximum absorption is shifted to an extent which is linearly related to the appropriate Hammett substituent constant. Substitution in the 2-position leads to a pronounced increase in the intensity of the long-wavelength band.     

Changes in the Properties of Synthetic Fibres in Thermal Aging

Thermal aging of complex lavsan, nitron, and anid fibres and lavsan and nitron yarn was investigated in the temperature region above the glass transition temperature (120, 150, 180°C) in the free state and with shrinkage for up to 300 h. It was shown that thermal aging of chemical fibres in the general case includes periods of structural and thermochemical aging. The kinetic characteristics of thermal shrinkage of chemical fibres and yarn in the first period of thermal aging were investigated. An exponential curve of shrinkage in time was obtained and can be used to predict the behavior of fibres and yarn in the first period of aging in the free state. The kinetics of the change in the strength and relative elongation at break was investigated in prolonged thermal aging of chemical fibres and yarn in the free (with shrinkage) and fixed (without shrinkage) states. The exponential dependence of the change in the fibre breaking characteristics on the duration of heat treatment was demonstrated. The change in the properties in prolonged thermal aging in the free and fixed states in the first stage of aging takes place differently. With shrinkage, the strength decreases and the deformability increases as a result of relaxation phenomena in the first stage, followed by a symbatic decrease in the strength and deformability as a result of thermal degradation processes in the second stage. In heat treatment in the fixed state, the change in the mechanical properties in the first stage is slight, while the strength and deformability simultaneously decrease in time as a result of thermal aging in the second stage. The quantitative characteristics found can be used to predict the change in the mechanical properties of chemical fibres and yarn in conditions of prolonged exposure to heat.     

Trends in the Development of Synthetic Fibres for Armor Material

Aramid fibres are still the fundamental variety of organic high-strength high-modulus fibres used in soft armor. In our opinion, fibres with high mechanical, primarily strength, indexes and with the corresponding level of supermolecular structure and its organization should be used for articles with different classes of protection. New kinds of chemical fibres and thread whose potentials as initial materials for soft armor could exceed the level of current textile materials are being developed throughout the world.     

Theory of Extremal Mechanical and Thermal Properties of Fibres and Needle Crystals. Comparison With Experimental Data

The current status of the problem of the extremal mechanical properties (modulus of elasticity, strength, thermal stability) of fibres and filamentary crystals that I elaborated over more than 50 years is presented. Two new integral energy indexes of the structure of polymers are proposed and evaluated — energy density of interatomic and intermolecular interactions, which determine many of the properties of oriented polymers and are important for predicting the mechanical properties. In addition to the theoretical modulus of elasticity and the theoretical strength of polymers (like the strength at absolute zero according to H. Mark and G. M. Bartenev), two new, practically important indexes are proposed — the maximum attainable moduli of elasticity and maximum attainable strength (in the given temperature-time conditions) are proposed. Models are developed and comparative calculations of the theoretical and maximum attainable moduli of elasticity, maximum attainable strength, and maximum thermal stability are performed with different methods for a number of linear (aliphatic and aromatic) and laminar (including carbon) structures. A comparison is made with the maximum values of the mechanical and thermal properties of the fundamental types of fibres and needle crystals based on aliphatic and aromatic polymers and materials with covalent bonds of laminar and three-dimensional structures. Oriented materials with the maximum possible properties among all of the elements of periods 2 and 3 in the Mendeleev Periodic System and their compounds — hexagonal boron nitride, graphite, and the linear carbon polymer, -carbyne, as a material with the highest modulus and strength possible in nature, are determined. New integral coefficients of completion of the structure of fibres as the ratios of the moduli of elasticity and strength attained to their maximum attainable values are proposed and evaluated. These coefficients characterize the level of the actually attained properties of oriented polymeric materials and consequently the perfection of the manufacturing technology. Ways of obtaining oriented polymeric materials with the maximum possible properties are discussed.     

合成纤维空气过滤材料的应用分析和评价

通过比较,分析评价了合成纤维过滤材料的各项性能,说明了它在空气过滤中获得广泛应用的原因。     

The Properties of Textile Materials Made from Modified Synthetic Fibres

Textured PCA fibre, which has a higher active surface and altered surface microtopography in comparison to standard PCA fibre, is characterized by better wettability. Capillary impregnation of knit fabric containing 50% textured PCA fibre and 50% cotton fibre is much greater (by 4.4 times) than capillary absorption of fabric based on standard PCA fibre. The knit investigated is a shrinkable fabric (group 3) used for mass production based on normative shrinkage values (12-14%). Incorporation of textured PCA fibres in the structure of knits based on cotton fibres increases the strength properties of the fabric by five times and markedly increases its stretchability.     

改进合成纤维染色牢度的新纺织化学品

合成纤维是纺织品服装的主要纤维源泉.随着人们对穿着要求和服用性能的不断提高,用合成纤维制成的织物的染色牢度满足高标准的要求已成为市场上的迫切需要.本文阐述了改进用于合成纤维染色的分散染料、酸性染料和金属络合染料的色牢度的新染料和新助剂,它们有利于纺织印染企业对染料和助剂的正确选择.     

Variant of the Relaxation and Retardation Spectra for Amorphous Crystalline Synthetic Fibres

The relaxation (retardation) spectrum of amorphous crystalline synthetic fibres is totally determined by the mean statistical relaxation (retardation) time and the structural coefficient that essentially characterizes the intensity of the relaxation (creep) process. With respect to the physical meaning, the relaxation function (retardation function) is obtained by integration of the relaxation (retardation) spectrum. Methods are developed for determining the relaxation and retardation spectra.     

Physicochemical Properties of Reinforcement of Epoxy Composites with Modified Synthetic Fibres

Modified synthetic fibres and filaments are thus distinguished by better adhesive properties, have a reinforcing effect in composite material, and affect curing of epoxy oligomer and formation of the structure of PCM made from them to a greater degree than standard fibres of the same chemical nature.     

Thermal and Mechanical Properties of Flax Fibres as Potential Composite Reinforcement

Scutched and hackled long flax fibres varying in retting degree, namely green, under‐retted and normally retted flax, and elementary fibres were tested for their mechanical and thermal properties. Tensile tests were performed on individual fibres and on bundles. The thermal stability is evaluated with thermogravimetric analyses (TGA) and determination of the mechanical properties after thermal exposure. For the investigated samples, no significant influence of the retting degree on tensile strength can be determined. Exposure to different temperatures results in a weight decrease and affects the mechanical properties of the fibres.     

新型节能减排环保型合纤用染料的发展

节能减排和环境保护是我国经济发展的基本国策,我国印染行业为了实现行业振兴开发了和正在开发不少节能减排新工艺与新技术。丈中阐述了为适应印染行业需要而发展的新型合成纤维用节能减排环保型染料和它们的应用,它们在振兴印染工业中将起着重要的作用。     

Activation of Synthetic Fibres with Transition Metal Salts in Dyeing with Anionic Dyes

The results of studies of the role of transition metal salts in increasing the sorption capacity of synthetic fibres are analyzed. A possible mechanism of activation of poly(ethylene terephthalate) fibres by transition metal compounds with organic ligands in dyeing with anionic dyes is proposed.__________Translated from Khimicheskie Volokna, No. 1, pp. 40–42, January–February, 2005.     

Estimation of the Parametres of Mechanotropic Gelation in Wet Spinning of Fibres

A mathematical analytical model of stretching of a jet of polymer solution was constructed. Estimations of the total mechanotropic gelation time, longitudinal rate, and rate gradient were obtained. It was shown that the order of the total gelation time for such a process in the system considered is within the limits of 1-10sec.