共查询到20条相似文献,搜索用时 31 毫秒
1.
AbstractThe focus of this work is to extract a natural dye for colouring camel wool as a substitute for synthetic dyes used in the Sadu House of Kuwait. Their target is to keep the tradition of tent and rug production natural in all its manifestations. Therefore, our task was to find an abundant source that provides a colour preferably red to purple. Hibiscus rosa sinensis (HRS) is an abundantly available plant in Kuwait that was explored for extraction of the red dye to colour camel wool permanently. The powdered petals of red flowers of HRS was extracted with 5% acetic acid which yielded a deep red colour that showed a great potential for woollen fibre dyeing. The use of mordants like alum and some metal salts manifested a wide range of fixed colours which intensified at 85 °C. The colours produced had excellent fastness and was accepted by the Sadu House. 相似文献
2.
ABSTRACTA series of crosslinking agents with different chain lengths were used to explore their effect on electro-optical properties of dye-doped polymer dispersed liquid crystals (PDLCs) film prepared by nucleophile-initiated thiol-ene click reaction. The influences of dye contents and temperatures on electro-optical properties were also investigated. It was found that the increase in chain length of crosslinking agent leads to the increase in driving voltage and the decrease in memory effect. The decrease in reaction temperature causes a decrease in driving voltage and an increase in transmittance. Particularly, the dye content could be optimised to obtain promising materials with minimum driving voltage and high contrast ratio for display applications. 相似文献
3.
New natural dye extracted from red prickly pear was used for dyeing wool with different types of mordents. The effect of mordant concentration on the color strength was discussed; the results obtained indicated that the color strength decreases with the increase of mordant concentration. The effect of the dye bath pH, salt concentration, dyeing temperature and dyeing time was also studied. The color strength and the dye uptake have exhibited high values. Good fastness properties of the dyed fabric were achieved.Antimicrobial activity of wool fabric dyed with this dye was tested according to diffusion agent. Test organisms as Escherichia coli, Bacillus subitilus, Pseudomons aeruginosa and Staphylococcus aureus were used and the results indicated that the samples exhibited a high inhibition zone.According to the available literature, this is the first report concerning a natural dye for fabric from fruits of red prickly pear plants. 相似文献
4.
This research has explored the effect of laccase (Denilite ІІ S) on the physical properties of the wool fabric and confirms
the anti-felting of wool. In the experiment, laccase was applied to a wool fabric and different characteristics including
weight loss, strength, alkali solubility, felting shrinkage, water drop absorption, and dye ability with madder were studied.
The surface morphology of the wool fabrics was also observed by scanning electron microscope. The results indicated that the
wool fabric treated with laccase has a higher water drop absorption, lower felting shrinkage, and lower values of a
* and b
*. Treatment of a wool fabric with 10% or lower percentage of laccase reduced the fabric weight but increased the tensile strength.
However, using higher concentration of laccase reduced fabric weight and tensile strength. The dyeing of laccase pre-treated
wool fabric with madder indicated a lower lightness. 相似文献
5.
Abstract The amount of methyl red, adsorbed on bare silica gel, has been determined for 32 samples having a specific surface area ranging from 10 m 2/g to 500 m 2/g, as determined by a BET method. A linear relationship between amount of dye adsorbed and specific area exists up to about 300 m 2/g. Beyond this value the amount of adsorbed dye does not increase correspondingly, which is believed to be due to the relative increase of micropores in the silica gel structure. It is proposed that the easily performed determination of the adsorbed methyl red can serve to estimate that part of the silica gel surface which is available for chromatographic interactions. 相似文献
6.
Abstract The surfactant-to-dye binding degree method was used to determine morphine hydrochloride and codeine phosphate. Neutral red and bis(2-ethylhexyl) sulfosuccinate (AOT) were used as the dye and surfactant, respectively, to form dye–surfactant aggregates. Addition of the drug resulted in a decrease in the dye–surfactant binding degree, proportional to the drug concentration. This was measured by monitoring the absorbance changes of the dye at 532 nm. Under the optimum conditions, the calibration graphs were linear up to 32 and 28 µg mL ?1 for morphine hydrochloride and codeine phosphate, respectively, with the corresponding detection limits of 0.40 and 0.35 µg mL ?1. 相似文献
7.
Summary The visible absorption spectra of dye crystals and the cross-section of wool fibre dyed with metal complex dye (C. I. Acid Yellow 161) were measured by means of a microspectrophotometer. The spectrum of crystal showed sharp and high maximum at 410 nm referred to as the peak from single crystal of the dye. The spectrum of the cross-section of dyed fibre showed two peaks of 410 nm (crystal-band) and 435 nm (monomeric state of the dye). Also, the electron diffraction pattern of the cross-section of dyed wool fibre showed the reflection ring of chromium. These results suggested that the dye should be present in the wool fibre in the monomeric, aggregate or crystalline state.
Zusammenfassung Mit Hilfe des Mikrospektrophotometers wurden die Absorptionsspektren im Sichtbaren von Farbstoffkristallen und von Querschnitten der mit Metallkomplex-Farbstoff (C. I. Acid Yellow 161) gefärbten Woll-Fasern gemessen. Die Kristall-Spektren zeigen ein scharfes und hohes Maximum bei 410 nm, das der Bande des Farbstoffkristalls zugeordnet werden muß. Die Spektren der Querschnitte gefärbter Fasern zeigen zwei Banden: seine bei 410 nm (Kristallbande) und eine bei 435 nm (Monomerbande). Auch zeigen die Elektronenbeugungen an Querschnitten gefärbter Fasern die Ring des Chromes. Dies läßt vermuten, daß in den Wollfasern Monomeres, Aggregate oder Kristalle des Farbstoffs existieren. 相似文献
8.
An amphiphilic crown-containing styryl dye ( 1) was synthesized, and the effects of irradiation, temperature, and alkali and alkali-earth metal ions on the conductivity
and optical spectra of its solutions in dioctyl phthalate were studied. Compound 1 in the trans-form almost completely exists as ion pairs (IP). Irradiation at a long-wavelength absorption maximum (λ max) results in a reversible increase in the conductivity and, hence, a degree of dissociation of IP (α); these parameters decrease
when complexes with metal ions are formed. The relaxation times for the photoinduced conductivity coincide with a decrease
in the extinction within experimental error in the 20–60°C temperature range. The photoinduced increase in α is caused by trans—cis-isomerization and an increase in steric hindrances for the interaction of the ClO 4
− anion with the N + atom of benzothiazolium in the cis-form of 1. The activation energies for the dark cis—trans-relaxation, absolute α values, and thermodynamic parameters of dissociation of IP in the trans-form, as well as the α values in a photostationary mixture of cis—trans-isomers, were estimated. The decrease in α after binding with metal ions is likely caused by the redistribution of the positive
charge to benzothiazolium through the conjugated system of 1. Correlations between the decrease in conductivity (decrease in α) and the hypsochromic shift Δλ max after the formation of complexes between 1 and metal ions were observed.
Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1296–1301, July, 1997. 相似文献
9.
Abstract We have observed the diffusion constants of a dye in several liquid crystals by forced Rayleigh scattering. In a liquid crystal which has a standard phase sequence of N-S A-S C, the diffusion anisotropy changes at the N-S A phase transition and increases with decreasing temperature in S A and S C phases. The diffusion constants exhibit a rather smooth decrease with decreasing temperature except an anomaly at the S A-S c phase transition. In a liquid crystal which has the antiferroelectric S CA phase, however, the diffusion constants show discontinuous increase and decrease at the S A-S c and the S c-S cA phase transition temperatures, respectively: the diffusion constant in S C is larger than that in the higher temperature S A phase. Anomalous signal increase and profile were observed at the phase transition temperatures, and were ascribed to the complementary transient grating due to the coexistence of two phases. 相似文献
10.
Abstract Among the vinyl monomers, acrylonitrile is the only monomer used for the production of synthetic fibers. Other vinyl monomers lack cohesive forces between the molecular chains of their polymers and, hence, can not compete with acrylonitrile [1]. Acrylic fiber has replaced wool in many major applications, particularly in hand knitting and hosiery garments. The majority of knitting yarns are usually bulky yarns which go into the manufacture of pullovers, sweaters, socks, etc. Acrylic fiber has been able to replace wool considerably in these applications. Blankets and carpets are other applications where acrylic fiber competes with wool [2] because of its high elasticity, color brilliancy, volumenosity, easy shampooing, resistance to pilling, good light and colorfastness values, etc. 相似文献
11.
Abstract Photograft copolymerization of methyl methacrylate on reduced wool (reduction done by treatment with thioglycollic acid, TGA) was studied at nearly 30°C using a Ce 4+ -oxalic acid redox initiator system in a limited aqueous system (2.7 mL water for 0.15 g wool). Reduction of wool for 16 h with 15% TGA solution produced optimum grafting effects. Percent grafting and grafting efficiency under different sets of conditions were studied and compared, and the mechanism of grafting discussed. Generation of grafting sites (radical centers) on reduced wool was more effective in the presence of light than in the dark. Percent grafting of 250–350% and grafting efficiency of 65-80% over a conversion range of 60–90% in 3–5 h were easily obtained. 相似文献
12.
The mesogenic behaviours of two azo dye liquid crystals, 1 and 4, differ because of the different length of terminal alkyl chains; azo dye 1 shows a SmB phase, azo dye 4 shows nematic and SmA phases during thermal processing. The molecular stackings of these two azo dye liquid crystals are compared on the basis of crystallographic studies to explain such unexpected mesogenic behaviour. 相似文献
13.
A string of novel heterocyclic mono azo dyes were synthesized and their utilization in dyeing different fabrics as wool and nylon were discussed. Thienopyridine azo dyes 4 and 6 were prepared by reaction of chloro acetamidederivative 2 with diamino compounds to yield 3 and 5 , followed by reaction with NaNO 2/HCl and coupling with nucleophilic reagent. One-pot reaction of chloro acetamide 2 with ammonium thiocyanat in solvent ethanol gave the unexpected thienopyrimidine derivative 7 , which contain two active sites, the former is primary amine that was able to form diazonium salt that coupled with N, N-dimethylaniline, resorcinol, and/or self-coupling to afford the azo dyes 8-10 , and the latter is active methylene group that underwent coupling with different diazonium salts to give the azo thienopyrimidine derivative dye 11-15 . The dyeing performance of these azo dyes had been investigated in terms of their dyeing behavior and fastness properties on different fabrics. Results showed that the color strength (K/S) values, as well as, washing, rubbing, and resistance to acid, alkali and light showed high efficiency of these heterocyclic mono azo dyes to dye wool rather than nylon fibers. 相似文献
14.
We have described a novel red biochrome, 514 Da in size, produced by solid-state cultivation of a bacterial isolate obtained
from garden soil. The growth requirements of the isolate, the chemical characteristics of the biochrome produced, and the
application of the biochrome in dying of silk, wool, and cotton fabrics have been studied. The biochrome obtained after 52 h
of incubation and having a λ
max of 535 nm was used for dyeing the fabrics. We found that silk, wool, and cotton fabrics dyed with this new natural red compound
have high color strength values and dye uptake along with good color fastness as well as antibacterial activity. 相似文献
15.
Quantitative HPLC and colorimetry are used to study color variations in dyeings with indigo, 6-bromoindigo, and 6,6′-dibromoindigo, the main components of the historic dye Tyrian purple. For the first time, visible light is identified conclusively as a cause of debromination of the leuco form of 6-bromoindigo. A dyeing run using 6-bromoindigo alone is found to yield a dyed fabric containing large amounts of indigo, when the vat is exposed to visible light. The extent of debromination is dependent upon the pH of the dye bath and also the source of the visible light. This information allowed development of a dyeing procedure which is demonstrated to give consistent colors through two passes. Quantitative HPLC analysis of extracts from the dyed fabrics indicates that the leuco form of 6-bromoindigo vs. the leuco forms of indigo and 6,6′-dibromoindigo has the strongest affinity for wool fabric. This is postulated to be due to attractive electrostatic interactions between the leuco form of 6-bromoindigo and wool. 相似文献
16.
Wool is the most important animal fiber used in textile industries, but its photostability is very low. Scientists have searched for new ways to increase the photostability of wool. As TiO 2 nano particles have features suitable for new applications, the UV-blocking power of nano TiO 2 may be used for protecting fabrics against UV rays. Treatment of wool with TiO 2 can be effective for controlling photodegradation. This study focused on protecting wool fabric against UV rays using nano TiO 2. To this end, oxidized and raw wool were treated with citric acid as the cross-linking agent and different concentrations of nano TiO 2. The whiteness and yellowness of wool fabric samples were reported. XRD patterns proved the existence of TiO 2 nano-particles on the wool surface. Finally, the results revealed that nano TiO 2 is a suitable UV absorber on wool fabric and its effect depends on concentration. 相似文献
17.
Treatment of dye 3 with sodium methoxide, morpholine, or diphenylphosphine gives the respective substituted derivatives 4, 5 and 6 in high yields. The reaction of 3 with sodium acetate followed by workup affords ketone 7 which is also obtained by demethylation of a methoxy derivative 4 under non-hydrolytic conditions. 相似文献
18.
Abstract Solar cells based on titania require the use of sensitizing dyes in order to make the absorption band coincident with the solar spectrum. The most successful sensitizing dyes are based on Ru‐bipyridyls and are chosen for their absorption and redox characteristics. In addition to absorbing visible light, the sensitizing dye injects an electron from its excited state into the band gap of the titania. The injected electron must be conducted through the titania to an electrode upon which the titania is coated. One of the energy wasting pathways available to the injected electron is back transfer to an oxidized dye species on the surface of the titania. We have discovered a simple means of alleviating this energy wasting pathway by anchoring aromatic amines, i.e., co‐sensitizers, at low concentration along with the Ru‐based bipyridyl sensitizing dye to the surface of titania nanoparticles. Our results indicate that there is a significant increase in cell efficiency (~15% at AM 1.5, area ≥1 cm 2) primarily due to an increase in current when these species are present on the surface in combination with the dyes. We will report our preliminary results on a series of co‐sensitizers, and we will compare these to literature findings which use similar compounds as either co‐adsorbed species on titania or as substituents on the sensitizing dye molecule itself. 相似文献
19.
Abstract A biosensor for continuous determination of lactate is presented. Lactate monooxygenase was immobilized covalently on nylon membranes, and the consumption of oxygen was measured by following, via a fiber optic bundle, the changes in the fluorescence of an oxygen-sensitive dye dissolved in 10- and 25-um silicone membranes placed beneath the enzyme layer. Oxygen is consumed as a result of the oxidation of lactate by the enzyme, and the decrease in its partial pressure is indicated by the fluorescent dye. For two types of sensors (with different nylon membranes and different thicknesses of the indicator layer) the analytical ranges were 2–50 mM and 0.3–6.0 mM, with response times (t 90) of 2.3–3.0 and 4.0–6.0 min, respectively. 相似文献
20.
Structural changes in wool fibers after annealing, i.e., storage at 45°C and 80% RH, have been investigated by using the method of laser Raman spectroscopy and by measuring birefringence and density of wool. The results show that CH 2 groups in wool give parallel Raman dichroism which increases very significantly after annealing. No increase in birefringence and density occurred after annealing. A hypothesis has been put forward which states that for minimum energy considerations in wool fibers the existence of intrahelix crosslinks other than hydrogen bonds is important. It is highly probable that a large number of electrovalent intrahelix crosslinkages exist between the suitable side groups on the main polypeptide chain in the α-helix of annealed wool. 相似文献
|