Fluoropolymer Fibres: Physicochemical Nature and Structural Dependence of their Unique Properties, Fabrication, and Use. A Review

Fluorine-containing fibre-forming polymers, fibres, and fibre materials have unique properties due to the presence of fluorine atoms. Totally fluorinated polymer materials are distinguished by the highest resistance to all kinds of chemical reagents and physically active media, low wettability by polar liquids, and other specific functional properties. In examining the physicochemical nature of the unique properties of fluoropolymer fibres and fibre materials with respect to the theory of chemical structure and D. I. Mendeleev's Periodic Table of the Elements, we found that they are due to the features of the fluorine atoms, which have the highest electronegativity of all elements, high ionization energy, high energies of bonds with carbon atoms, and simultaneously shield the molecular chain from external effects. Fibre-forming fluoropolymers, fibres, and fibre materials made from them have high resistance to external effects, biostability and bioinertness, and highly effective protective and other functional characteristics. This relates to the totally fluorinated materials PTFE, HFP, and CP-TFE-HFP to the greatest degree. Fibres and fibre materials based on totally fluorinated polymers (PTFE, HFP, CP-TFE-HFP) are placed in a special group for use in articles utilized in extreme conditions in exposure to especially aggressive media and other external active effects where the use of other kinds of fibres and fibre materials is difficult or impossible because of their low stability and rapid destruction.     

Modification of Polyester Fibres to Give Them Nonstick Properties

A method for modifying polyester fibres by incorporating a fluorine-containing polymer in the surface layer of the fibres was developed to give the fibres nonstick properties with respect to liquids of different chemical nature. It is best to use polyfluoroalkyl acrylate latex stabilized with a cationic or nonionogenic SF for modification, since it gives the fibre antistatic as well as nonstick properties.     

Complex Metal Cations as Modifiers of the Properties of Polyester Fibres

Treatment of Lavsan fabric with a solution of chromium(III) benzoate complexes causes the highest rate of fixation of acid dye by the fabric and the highest equilibrium sorption, 2.5 times higher than this index for untreated fabric. The fabric also acquires higher capillarity. A simple method is proposed for production of chromium(III) benzoate and salicylate complexes and their composition is investigated spectrophotometrically as a function of the ratio of chromium ions and acid molecules in the solution.     

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.     

Autoadhesive Bonding of Modified Polyester Fibres

An efficient method of autoadhesive bonding of polyester fibres in a high-strength nonwoven textile was developed. The method includes application of a small amount (0.25 wt. %) of a new organosilicon modifier — oligo(ethoxy)(isobutoxy)siloxane — on washed fibres and pressing under a pressure of 2 MPa for 2 min. The method allows reducing the pressing temperature by 5-6°C and elimiantes the use of 30-40 wt. % traditional bonding substances.     

Change in the Properties of Textile Materials Containing Polyester and Cellulose Fibres Caused by Moisture

The hygroscopic properties, swelling, and change in the mechanical properties of thread containing polyester and natural cellulose fibres and one-component thread (yarn) were comprehensively investigated. The kinetics of swelling of textile materials is described by an exponential equation, and the coefficients of this equation are determined. It is shown that for yarn made of fibre blends, the equilibrium sorption and swelling values are satisfactorily described by additive dependences on the component content. It is found that equilibrium swelling is 2-3 times greater than equilibrium sorption of water vapors from air due to different mechanisms of binding of moisture with the fibres. It is shown that the breaking characteristics of flax and cotton varieties of yarn increase in swelling due to an increase in the frictional interaction between the fibres.     

Solvent-assisted Dyeing of Nylon 6.6 and Polyester Fibres

The results of laboratory semi-bulk and bulk trial work on the dyeing of nylon 6.6, with anionic dyes in the presence of n-butanol, in an aqueous dyebath are described. The method gives improvements in coverage of barre which cannot be achieved in other ways, without detectable adverse effects on the physical properties of the nylon 6.6 or the colour and fastness properties of the dyes. Results of work by a similar, solvent-assisted dyeing method for polyester fibre are given. Improvements in migration and speed of fixation of dye in the presence of n-butanol are noted, but these are similar in magnitude to the improvements obtainable with conventional carriers for polyester dyeing at much lower concentrations. The method is likely to be commercially viable only if a substantial proportion of the butanol added to the dyebath can be recovered for re-use. This should theoretically be possible, but experimental confirmation of the process has not yet been obtained.     

Prediction of the Structural Parameters of Fabrics Made from Chemical Fibres. Part 2. Determination of the Structural Parametres and Mechanical Properties of Chemical Fibres

A method was developed for preparing the initial data for prediction of the structural parameters of fabrics made from chemical fibres. The values of the geometric and mechanical characteristics of polyester fibres and viscose yarn were obtained.     

Production and Use Of Polyester Fibres Today and Tomorrow

World production of polyester fibres and filaments in 2002 attained a record level: 20.4 million tons, including 11.8 million tons of complex filaments (+8%) and 8.6 million tons of fibres (+6%). The share of the former has increased at high rates in recent years and is now 58%, which is 16% higher than the share of fibres and twist. New kinds of fibres and filaments based on different polyesters are being manufactured on an industrial scale: liquid crystalline polymers — Vectran HS and Vectran M, poly(ethylene terephthalate) (industrial fibres), poly(butylene terephthalate) (fibres with high dyeability), and poly(trimethylene terephthalate) (fibres and filaments), as well as fibres with low combustibility, antibactericidal, conducting, and other fibres.     

Structural, Physicomechanical, and Sorption Properties of Ternary Acrylonitrile Copolymer Fibres

When itaconic acid (IA) is replaced by vinylcaprolactam (VCL) in ternary AN:MA:IA (acrylonitrile:methyl acrylate:itaconic acid) copolymers, fibres similar in structure to industrial Nitron fibre are obtained, and they have a higher capacity for orientation the larger the amount of VCL added to the copolymer. The fibres obtained have higher physicomechanical properties and higher hydrophilicity and dyeability with disperse dyes than Nitron fibres. The values of the diffusion coefficient of equilibrium-sorbed dye, activation energy, and some thermodynamic properties are calculated. An increase in the VCL content in the copolymer and an increase in the temperature cause an increase in the degree of fixation of the disperse dye in the fibre. In ordinary dyeing conditions, a high residual dye content in the fibre can be attained.     

Some Relationships between Dyeing Kinetics of Polyester Fibres and Their Structural Changes Caused by Heat-Treatment and Dveine Conditions

The rate of dyeing of a poly (ethylene terephthalate) has been characterized as a function (a) of the tension applied before heat setting, (b) of the shrinkage allowed during heat setting, and (c) of the tension applied before dyeing. Very small variations in applied tension lead to very significant differences in rate of dyeing. Furthermore, in order to correlate the dyeing results with changes in the fibre, the structure of the polyfethylene terephthalate fibre was determined as a function of the tension applied before either heat setting or dyeing. The structural parameters studied were crystallinity, crystalline orientation, birefringence, amorphous orientation factor and water swelling at 130d?C. The variations in dyeing kinetics may be due to changes of amorphous orientation on the one hand and to changes in tortuosity, size and volume of pores on the other.     

Molecular Mechanisms of Disperse Dyeing of Polyester and Nylon Fibres

The kinetics of the dyeing of polyester fibres with disperse dyes have previously been discussed in terms of a model in which the only forces of interaction between dye and polymer are those that give rise to mutual solubility. The rate and extent of dyeing depend on the size and shape of the dye molecules and the detailed structure of the fibre. The concentration profiles of dye within single filaments of polyesters and nylons have now been determined by a new method termed ‘optical sectioning’, in which an image of a filament is scanned by a narrow slit. The dye distributions are found by comparing experimental transmission values with those calculated by a computer for a model system in which various parameters can be adjusted. For the polyester-dye systems the rate constant of transfer of dye from dyebath to fibre (k₁) was the same as the rate constant of diffusion away from the interface (k₂). Some nylon-dye systems, on the other hand, behaved as if k₂ = k₁, whereas others behaved initially as if k₁ = k₂ but later as if k₂ > k₁. Apparent diffusion coefficients were also derived from sorption measurements and were found to fall as the dye concentration in the fibre increased. Measurement of the orientation of the dye molecules by optical dichroism showed that the dye molecules entering the filaments late in the dyeing process were more highly orientated than the earlier ones. The decrease in diffusion coefficient has been interpreted in terms of the observed higher orientation, as resulting from a greater entropy of activation in the diffusion process.     

Tuning the Properties of Shape-Memory Polyurethanes via the Nature of the Polyester Switching Segment

Shape-memory polymers that contain semicrystalline domains with a melting temperature (T_m) above and a crystallization temperature (T_c) below physiological temperature as fixing elements are useful to create medical devices or implants that can be custom-shaped inside or around the body. With the goal to expand the palette of materials that exhibit such properties, a series of segmented polyurethanes (PUs) containing different crystallizable polyester segments is investigated. The nature of the polyester, its molecular weight, and the ratio of hard to soft segments are systematically varied and the effect on the mechanical, thermal, and shape-memory properties of the various PUs is studied. Poly(1,12-dodecylene dodecanoate), poly(1,6-hexylene dodecanoate), and poly(ethylene sebacate) (PES) are selected as crystallizable polyester segments. The PES-based PUs display T_c values of 25–35 °C and a T_m of 60–63 °C, and allow good shape fixing at 37 °C.     

N-异丙基丙烯酰胺功能性共聚物的结构及特性研究进展

N-异丙基丙烯酰胺共聚物是一种新型的智能材料,可用于制备药物控释材料、酶的固定材料、脱水剂等。概述了N-异丙基丙烯酰胺共聚物及其各类共聚单体的大分子结构、氢键效应及刺激响应性等特性。     

The Effect of Dye Penetration on the Resultant Colour of Polyester Fibres

Presented at the 13th Congress of the International Federation of Associations of Textile Chemists and Colourists in London on 21 September 1984. The colours of a series of ring-dyed polyester filaments, in which the dye distributions were measured by an optical sectioning method, were compared with the colours of uniformly dyed filaments of the same overall dye content. Colour measurements were made on randomised pads of chopped fibre using a Zeiss RFC3 colorimeter. It was found that the colour differences between ring-dyed and uniformly dyed filaments were greatest for light dyeings. Because the dye distributions in ring-dyed filaments can change during subsequent textile processing the need to avoid ring dyeing is emphasised.     

Carbon Fibres with Specific Physical and Physicochemical Properties Based on Hydrated Cellulose and Polyacrylonitrile Precursors. A Review

A wide assortment of carbon fibres (CF) made from readily available hydrated cellulose (HC) and PAN staple fibres and twists, textile and other fibre materials, including heat and chemical-resistant composites, has been developed. The use of these materials is based on their unique thermal, physical, physicochemical, and biological properties. The precursor fibres have their own characteristics and the properties of the CF and CFM made from them are correspondingly different. The economic aspects of their fabrication differ slightly, and CF made from PAN perhaps now have some advantages. However, in the near future, the price ratio will vary in support of cellulose fibres since products made from crude oil, natural gas, and coal are gradually becoming more expensive. The economics of small-tonnage fibres with original specific properties should be taken into consideration based on the efficiency of their use. The uniqueness of these fibres gives those which are irreplaceable and most effective the right to life. In this respect, all of the CF and CFM examined are important and promising. Far from all of the possible applications of these fibres have been discovered and implemented, which makes them even more promising for the future.     

尼龙和聚酯短纤维的长度对其与天然橡胶氯丁橡胶复合材料性能的影响

本就尼龙，聚酯短纤维的长度对尼龙－天然橡胶以及聚酯－氯丁橡胶复合材料的物理性能和溶胀性能的影响进行了理论研究。实验结果表明：这两种短纤维橡胶复合材料的撕裂强度，２０％定伸应力随短纤维长度增加而增大，抗溶胀能力增强，拉伸强度则在短纤维最佳长径比条件下最好。尼龙，聚酯短纤维经Ｄ法预处理后，其复合材料的各基性能均有较大提高。