Extraction of juglone from Pterocarya fraxinifolia leaves for dyeing,anti‐fungal finishing,and solar UV protection of wool

In many countries, the search for new sources of natural colourants has recently been intense. This paper deals with the extraction procedure, dyeing behaviour, antifungal activity, and ultraviolet protection of Pterocarya fraxinifolia as a new natural source of dyes. Juglone was found as the main extracted compound after characterisation by ultraviolet‐visible spectrophotometry and Fourier transform infrared spectroscopy. Mordanting and subsequent dyeing of wool with extracted juglone were then performed to study the dyeability and antifungal activities. Three metal salts, aluminium sulfate, copper sulfate, and iron sulfate, were used as chelating materials. The colorimetric properties of samples were evaluated using a reflectance spectrophotometer. Furthermore, the washing and light fastness properties were tested according to ISO 105‐CO3:1989 and ISO 105‐B01:2014. Interestingly, we found P. fraxinifolia to be a source of strong antifungal compounds against microorganisms. Extracted juglone also exhibited strong protection activity against solar ultraviolet rays.     

Extraction of polyphenolic substances from bark as natural colorants for wool dyeing

In Europe, considerable amounts of bark are available from wood‐processing industries such as forestry and timber production. Polyphenolic components can be collected by hot water extraction. The extracted compounds can then be applied as colorants in textile dyeing operations. In this study, a comparative assessment of four different tree species with regard to their colouristic potential for wool dyeing was performed. Aqueous extracts from alder, ash tree, spruce and oak bark were prepared and analysed for their total phenolic content and ultraviolet (UV) absorption at 360–370 nm. The extracts were used for meta‐mordant dyeing by adding iron sulphate mordant (FeSO₄ × 7H₂O). For comparison, iron salt‐based dye lakes were prepared and used in dyeing experiments. For each tree species, a specific correlation between the total phenolic content of the dyebath and the colour depth in terms of K/S and CIELab coordinates was observed, both for the aqueous extracts and the dye lakes. Based on this relationship, standardisation and quality control of raw materials and dye lakes can be installed as important stages in the industrialisation of natural colorants from bark. The preparation of concentrated dye lakes permits formation of a concentrated colorant as dye product, which then can be standardised and delivered to textile dyehouses, similar to synthetic dyes. The preparation of dye lakes offers a relevant route towards achieving the commercialisation of bark extracts as natural colorants.     

Dual permeation of acid dyes through nylon 6 membrane

Permeation of acid dyes in nylon 6 membrane was measured and analyzed by the dual sorption and diffusion mechanism, comprising partition and Langmuir-type modes. The results were compared with our previous work on diffusion in the same system by the film roll method. Diffusion coefficients of both dye species were found to be similar in magnitude.     

Extraction of natural dyes from Alpinia blepharocalyx K. Schum. for dyeing of silk fabric

Natural dyes were extracted from the leaves and stems of Alpinia blepharocalyx K. Schum. Analysis of the designed experiment revealed that extraction at a plant/water ratio of 1:20 could reach an optimal production of natural dyes when extraction was performed at 80 °C, for 4 h, under 20 min ultrasound, in the presence of 10 g/l sodium hydroxide, and with two extractions. The extracted natural dyes were applied to the dyeing of silk fabrics using different methods, including or excluding a mordant. It was found that mordants had a significant effect on the colour of dyed silk fabrics. The silk fabric dyed with the pre‐mordant method using potassium aluminium sulphate as a mordant showed a bright yellow with a higher colour strength. The optimal dyeing conditions were reached when the extracted natural dyes were pre‐mordanted with 10 g/l potassium aluminium sulphate at pH 6, and for a 20 min dyeing time.     

Dyeing of nylon with reactive dyes. Part 1. The effect of changes in dye structure on the dyeing of nylon with reactive dyes

The dyeing behaviour of seven red commercial cellulosic reactive dyes, all based on the same chromophore and possessing one or more reactive group, and one to three chromophore units, were evaluated on nylon. Fixation levels appeared to be independent of the number of either reactive groups or chromophore units. Also, the degree of sulphonation, per se, appeared to have little effect on fixation, whereas the type of reactive group was important. The major determinant of dye fixation appeared to be associated with the shape of the molecule and the type, not the number, of reactive groups.     

Developing critical extrusion parameters for nylon 6, nylon 66, and nylon 46 polyamide from the rheology data

This paper describes a new approach to the rheological characterization of engineering plastics such as nylon 6, 66, and 46 polyamides using a capillary rheometer. The melt viscosity data as a function of temperature, shear rate, and residence time were measured and evaluated to demonstrate how to accurately predict critical extrusion parameters, such as barrel temperature profile, stock temperature window, and the screw design requirements, for extruding strip, tubing, and profiles. The results of this work provide a practical and simple quality control tool to select a polyamide resin for optimum processing, and to develop critical processing parameters for extrusion.     

Dyeing of nylon with reactive dyes. Part 2. The effect of changes in level of dye sulphonation on the dyeing of nylon with reactive dyes

Four mono-functional reactive monochlorotriazinyl (MCT) dyes, each derived from the same chromophore and possessing a single monochlorotriazinyl reactive group, but differing only in degree of sulphonation, were synthesised and evaluated on nylon. The colour yield, degree of exhaustion, fixation, and the fastness properties of each dye were assessed. Initial exhaustion, at pH 4, was high for all dyes but percentage fixation, via covalent bond formation, increased with increasing levels of sulphonation. In all cases fixation efficiency reduced markedly with increasing concentrations of dye applied.     

Studies on dyeing and mechanical properties of nylon 6 filaments subjected to swelling treatments

Drawn nylon 6 filaments were subjected to swelling treatment with benzyl alcohol and aqueous solution of phenol and formic acid under slack condition and under tension. The pretreated samples were dyed with a disperse dye Foron Yellow SE-FL (C.I. Disperse Yellow 42). A considerable increase in the equilibrium dye uptake was observed as a result of swelling treatment. Studies on lateral order by X-ray methods showed that lateral order has increased considerably as a result of preswelling treatment. This apparent contradiction, viz., increase in lateral order and at the same time increase in dye upstake, is explained as due to increased void volume. Studies on mechanical properties showed that the percentage elongation is increased as a result of swelling treatment under slack condition in spite of increased lateral order. This is explained as due to the slippage of chain-folded crystallites.     

微波辐射提取石榴皮单宁的研究

以丙酮为提取溶剂,采用微波辐射提取石榴皮中的单宁,考察了溶剂浓度、微波功率、微波辐射时间、液料比等因素对单宁提取量的影响。结果表明,当溶剂体积浓度50%、微波辐射功率320 W、微波辐射时间5 m in和液料比18∶1(g/g)时,单宁的提取量为268.54 mg/g,比普通水浴提取提高了30.39 mg/g。     

Synthesis and dyeing properties of polyvinylamine dyes for cotton

Novel polyvinylamine dyes were designed and synthesised from poly(N‐vinylformamide‐co‐vinylamine) and reactive dyes, then used to dye cotton fibres by the dip‐pad‐steam process, with the dyeing methods being examined in detail. Each polyvinylamine dye was fixed to cotton without a crosslinking agent through covalent bonds formed between the reactive group of the dye and the cotton fibres. A fixation of 99% was achieved, with grades of 4 and 4‐5 wash and dry‐rub fastness, respectively.     

Use of azoic dyes for dyeing Terlon fibre

The use of components for formation of azoic dyes in certain stages of fabrication of Terlon fibres allows obtaining dyed fibres with high color fastness and preservation of the basic physicomechanical properties of the fibre.Russian Correspondence Institute of the Textile and Light Industry, Moscow. Avtokhimeks TOO. All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 3, pp. 13–14, May–June, 1995.     

Diffusion of dye mixtures in nylon 6. Binary mixtures of disperse dyes

The diffusion of binary dye mixtures of markedly different chemical constitutions (4-nitro-4′-aminoazobenzene and 1-amino-4-hydroxyanthraquinone) and of similar ones (1-amino-4-hydroxyanthraquinone and 1,4-dihydroxyanthraquinone) into nylon 6 film was examined. Apparent diffusion coefficients of dyes in the mixture within a single dyeing were determined by the film roll method at 60°, 70°, 80°, and 90°C. Diffusion coefficients of individual dyes used in a mixture of chemically dissimilar dyes are found to change little in comparison with single dyeings, while diffusion coefficients of dyes of similar structures are decreased appreciably. It is suggested that the latter effect is due to the interaction between two dyes in the fiber substrate.     

Model dyes for optimizing the dyeing of polyamide

Model disperse azo dyes, containing a salicylic moiety, hydrophobic alkyl chains and usual substituents, allowed the investigation of the effects of these structural variations on dyeing properties. By combining the results of both equilibrium and rate studies, some interesting structures for practical purposes could be identified.     

Interpretive nonlinear viscoelasticity: Dynamic properties of nylon 6, nylon 66, and nylon 12 fibers

Nonlinear response of nylon 6, nylon 66, and nylon 12 fibers to sinusoidal straining under relatively large strain amplitude is analyzed in terms of the changes in properties during the straining, i.e., the change in modulus, change in internal friction and change in structure which involves energy release or absorption in straining. Modulus generally increases with strain but it decreases with increase of strain amplitude, the effect of strain amplitude being largest with nylon 6 and smallest with nylon 66. Mechanical loss increase with the increase of strain amplitudes in nonlinear manner, and the magnitude of change is largest with nylon 66 and smallest with nylon 6. During the extension phase, structural change occurring in nylon 6 is predominantly an increase in order or orientation while that with nylon 66 is crack opening or cavitation. Various aspects of the experiments and analysis of the data are described in detail.     

Natural dyeing and antibacterial activity of atmospheric‐plasma‐treated nylon 6 fabric

Atmospheric plasma treatment as an environmentally friendly method was employed to modify the surface properties and improve the absorption of natural cationic dye on to nylon 6 fabric. Nylon fabric was treated in atmospheric air plasma, and the surface characteristics of the fabric were evaluated using attenuated total reflection Fourier Transform‐infrared analysis, scanning electron microscopy, and a wicking test. The effects of plasma treatment and mordanting with copper sulfate on the dye uptake of the samples were investigated. Plasma‐treated and mordanted samples showed the highest colour strength when dyed. The antibacterial activity of samples was evaluated according to AATCC test method 100‐2004. Premordanting with copper sulfate showed a synergistic effect on the antibacterial properties of the dyed fabric. The plasma‐treated and copper‐sulfate‐mordanted sample showed acceptable antibacterial activity against both gram‐negative and gram‐positive bacteria when dyed with an extract from Berberis vulgaris, berberine.     

The potential for high performance fiber from nylon 6

A review has been attempted in this article of the multidisciplinary character of the development of high performance fibrous materials. The effort has focused on both the theoretical recognition of the possibility of such materials and a recounting of significant aspects of the art for producing fiber with high performance characteristics.A knowledge of the primary valence bonds in a basic molecule, the atom configuration along the backbone of the molecule and the valence angles permits one to utilize spectroscopic inputs to compute the theoretical maximum modulus of elasticity in a given ideal fiber structure. An infinite replication of such molecules, all parallel one with the other is envisioned as this ideal structure. In order to obtain the ultimate modulus values, it is necessary to know the three-dimensional arrangements between chains, knowledge which is usually derived from X-ray diffraction studies. The ultimate tenacity, on the other hand, is dependent on some approximation of the intermolecular potential between polymer chains. The Morse potential,⁶¹ a strictly empirical relation describing the force of separation of polymer segments, has proved to be one of the simpler methods for obtaining an estimate of ultimate tenacity. Other intermolecular potentials may or may not provide similar estimates. The Morse potential provides an explicit elongation at the point of break if this is based on maximum force of separation. It varies with the value of U₀, the dissociation energy, and a parameter a, characteristic of an inverse length which is determined in turn by spectroscopic data.Based on the initial work of Flory, lattice techniques may be utilized for understanding and describing the development of order in infinite molecules when the ordering process is subjected to an external biasing probability imposed by the presence of some type of an ordering field. One could envision the macroscopic picture of extensional and stretching flows and similar macroscopic processes as resulting in the presence of this microscopic biasing probability. This probability influences the conditions for the formation of mesophases as a function of polymer concentration.Polymer nucleation has been described as being due to the development of a sequence of nuclei along a predetermined aligned structure. This structure is perhaps brought about by a particularly long molecular component accidentally extended in a particular direction due to some aspect of the microscopic processes. These processes are responsible for initiating and maintaining phase separation in the polymer solution or melt. Phase transformation of the ordered structures is carried out by the empirical art, leading to practical processes for the development of extended chain structures within the solidfying polymeric system.Quiescent crystallization from solutions of nylon 6 and similar polymers is often found to produce “lath-like” crystals. These are distinguished from the dynamically induced fibrous crystals known as shish kebabs. The latter had been found earlier in simpler polymeric systems that have led to high performance fibers, notably polyethylene.A casual examination of the crystal structures of nylon 6 formed by various extrusion and other proceses may suggest to the reader that the fibrous crystals of nylon 6 involve a structure where the hydrogen bonds between molecules tend to be aligned with the axis of the fibrillar structure. The molecules are oriented at right angles to the fibril axis. However, closer reading of this literature and review of the work by at least one author¹³¹ suggest that another backbone habitat can be formed, at least in the case of nylon 4. The work of Pennings⁹⁸ involves a strong solvent which permits, in quiescent crystallization, the formation of lath-like crystals which have the hydrogen bonding coinciding with the axis of the lath, which was also reported by Kyotani.¹²⁴This is to be contrasted with the work of the present authors,¹⁵⁷ involving the shearing of a highly concentrated polymer solution in meta-cresol, which suggests that fibrillar crystals may be obtained quickly in a threadline, producing a reasonably good fiber or filament which will have the proper orientation. This should involve an orientation of the primary backbone of the molecule parallel to the fibrillar axis. If this possibility exists, as one would expect from the theoretical work of Vasilenko,⁷³ we are led to believe that fibrils with the molecules oriented parallel to the fibril axis will be the dominant features in such fibers.Given that this is feasible, then one can lean on the results obtained in the commercial products known as Kevlar^® and Spectra^®, and conclude that a nylon 6 filament containing fibrils with microstructure of the kind suggested will, in fact, have a good chance to exhibit high performance characteristics. This is further supported by the Toyobo patent¹⁹ and the more recent results of Pennings²¹ which involved a different solvent from the ones used earlier,⁹⁸ suggesting that there is a possibility of producing a filament which has a tenacity of up to 1.16 GPa and modulus of up to 19 GPa.It is clear that a preferred process for the production of a high performance fiber may well involve a substantial departure from any traditional extrusion process, as evidenced by the work of Pennings on polyethylene. Even that early work on polyethylene has been further modified by Penning in an attempt to produce high performance properties in nylon 6. As further evidence of the use of nontraditional processes in forming high performance fibers we cite the work of Allied in producing high performance Spectra^® and of du Pont in producing high performance Kevlar^®. It, therefore, seems necessary that one should attempt to modify either a melt process or a solution process in trying to produce high performance fibers from nylon 6.Recently George^162,163 and Lim¹⁶⁴ have suggested that all high performance fibers involve at least a two-element sequence in which an initial fibril is converted into a chain-extended, close-packed form near the end of the total process of formation by a load induced phase change. Pennings¹⁶⁵ has shown this as well as Sawyer.⁸⁴ Very early work by Kauffman and George¹⁶⁶ deduced a change in the fiber diameter in the later stages of deformation of a drawn nylon 6,6 filament.In our opinion, the area that presents the most promise is the extrusion of plasticized melt. A similar sort of preliminary probe was reported by Sawyer in his Ph.D. thesis in 1984 involving polyethylene terephthalate, wherein he heavily plasticized the polymer and then melt extruded the result. The resulting fibers, while amorphous to X-ray diffraction, produced, when stretched and annealed in a restrained condition, extremely high birefringence. Small sections of this fiber also showed sonic moduli of 10 to 20 GPa. The principal result of this work seems to be that given an adequate molecular weight and a properly modified extrusion process it should be possible to obtain a high performance fiber having microfibrillar structure from the nylon 6 polymer system.     

Carbon black as a dulling agent for nylon 6 filaments and the lightfastness of dyes on dulled filaments

Nylon 6 filaments containing 0–1.5% carbon-black pigment are dyed to different depths of shade. The colour on the substrate is evaluated on CIELAB a* b* diagrams at given concentrations of carbon black and dye. The carbon-black pigment acts essentially as a neutral dulling agent and only with a few dyes does it appear to alter the hue angle slightly. Thus, it is possible to use nylon 6 filaments containing carbon-black pigment to produce dull shades by the overdyeing process. The dyed samples thus produced are exposed to mercury-lamp light as well as daylight. The lightfastness is evaluated visually using the Blue Wool Scale. There is a remarkable improvement in the lightfastness of all dyes on nylon 6 containing carbon-black pigment. The carbon black in the filament appears to protect both the dye and the polymer from the degrading action of actinic radiation. However, the remarkable improvement in the lightfastness is essentially due to the optical effect.     

Dyeing properties of oxygen low-temperature plasma-treated wool and nylon 6 fibres with acid and basic dyes

Wool and nylon 6 fibres treated with oxygen low-temperature plasma were dyed with acid and basic dyes. Despite the increase of electronegativity of the fibre surface caused by the plasma treatment, the rate of dyeing of wool was increased with both dyes, while that of nylon 6 was decreased with the acid dye and increased with the basic dye.     

Biconstituent fibers from segmented polyurethanes and nylon 6

The characteristics of Monvelle, a new biconstituent fiber from nylon 6 and a segmented polyurethane, are reviewed briefly, and some of the technical problems inherent in producing such a fiber are discussed. The characterization of two series of polyurethanes which can be melt spun is given in detail. The chemical composition of the hard segment was maintained constant, being derived from 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol, in all polymers. In one series using poly(butylene adipate) of MW 2000 as the soft segment, the average hard segment content was varied from 33% to 54%. In the other series, the hard segment content was held at 43%, and three additional soft segments, each at MW 2000, were used: poly(ethylene adipate), polycaprolactone and poly-1,4-oxybutylene glycol (PBG). Characterizations include molecular weight distributions, thermal analysis, rheological studies, and selected small-angle and wide-angle x-ray diffraction and polarized light microscopy. Crystallinity, melt viscosity, and activation energy of flow increased with increasing hardsegment content. Changes in the polyester soft segments had little effect on the properties studied, but with PBG the crystalline melting point of the polymer, without annealing, was higher and the melt viscosity was slightly higher than corresponding polyester-based samples, in agreement with previous reports of sharper phase separation in polyether urethanes, compared to polyester urethanes.