فناوری در رنگ، رنگ دهنده ها و پوشش دهنده ها
سال:1387 | دوره: | شماره: |تعداد مقالات:7

In this study, a derivative method is applied for the determination of dye concentration in fabrics dyed with tricomponent dye mixtures. The reflectance of spectra of the samples were recorded between 400 and 700 nm. Initially,the obtained (K/S) spectra were divided by the spectrum of a standard sample dyed with two of the components in the ternary mixture and the derivative spectra were calculated. Then, the amounts of the dyes were determined by implementing or carring measurements in suitably selective wavelengths in the required spectra derivative ratio. Results indicated that the developed spectra derivative ratio (K/S) method is more accurate than the normal Kubelka-Munk.

The development of an optical pH sensor based on immobilization of quinizarin (1,4-dihydroxyanthraquinone) on a triacetylcellulose membrane was described. The resulting membrane exhibited fast color change from yellow to violet, while changing the pH in alkaline region. The immobilized quinizarin showed a broader dynamic range from (pH 9.4-11.4) with respect to free form (pH 8.8-10.4). The sensor response was fully reversible and fast (<20 s) under the batch conditions with pH between 7 and 12.5. The sensor showed excellent long term stability (more than three months) and high reproducibility (R.S.D. less than 2%). The Ka values for free and immobilized dye were evaluated and the chemical reactivity of the quinizarin in solution and after immobilization was also described.

In this work, raw fibers of a local species of stabraq (milkweed) were scoured, bleached and blended with cotton fibers with a ratio of 75/25 (cotton/stabraq). The improved stabraq fibers, scoured and bleached cotton and the blended fibers were spun into fine yarns and then they were subjected to dyeing with two types of reactive dyes namely, cold brand and high exhaustion brand reactive dye at 1% omf in a liquor ratio of 20:1, in the exhaustion dyeing method. The extent of exhaustion, colour strength and other colorimetric parameters of the dyeing were determined and the results were compared. The results suggested that the dyeability of stabraq fibers with two reactive dyes used, resembles that of cotton yarns more closely, and the blended fibers exhibited superior dyeing behavior than the alone fibers.

Silk yarns were dyed by using commercial basic, reactive and pre-metallised acid dyes. An aftertreatment with a commercial synthetic tanning agent (syntan) was applied to the dyeings and the aftertreated dyeings were further treated with metal salts in an attempt to improve wash fastness properties. When all samples (untreated, syntanned and syntanned/ backtanned speciments) were subjected five times to a repeated wash testing (ISO 105CO1), it was found that the fastness, to repeated wash testing, was improved, as expected by an aftertreatment with the commercial syntan. Further, significant, the two-stage, syntan/metal salts aftertreatment raised the level of wash fastness of the syntanned samples.

Today, natural colorants are emerging globally due to their safety and environmental friendly characteristics. Natural dyes have been employed in dyeing Persian carpet piles for many years. Food and fruit industry wastes are one of the main sources of colorants which can be employed for textile coloration. Eggplant (Solanum melongena), a member of the family Solanaceae, is used in food recipes. Anthocyanin pigments are responsible for the dark purple color of its skin. In this research, dyeing wool fibers was carried out using powdered skin of eggplant. For this purpose, the Iranian wool was first treated with some metal salts including Fe(II), Sn(II), Cu(II), Cr(VI) and Al(III). These salts are commonly used as mordant to improve the wash and light fastness of natural dyed textiles. The wool fiber was then dyed with 50% owf powdered skin of eggplant. The colorimetric properties of the dyed yarns were evaluated using a reflectance spectrophotometer. The wash and light fastness of the samples were also measured according to ISO 105-CO5 and Daylight ISO 105-BO1. Results showed that skin of eggplant is a potential source for dyeing wool fibers.

As a very important coating material in different applications, bitumen is a complex mixture of different chemicals. It is generally accepted that the principle of time-temperature superposition (TTS) holds for this material. In this study rheological measurements were carried out on four different bitumens. Different representations of the experimental data were examined to check failure or holding of TTS for this complex system. Due to differences in dynamics of components, discontinuities were observed in versus G* curves for all four bitumens. It was concluded that the TTS fails to be applied for the studied bitumens.

Microwave dyeing was carried out under a variety of conditions in terms of the power and time of a microwave to investigate the effects of microwaving on the dyeability of acrylic fibers. It was found that the dyeability of acrylic fibers were significantly improved under microwave irradiation caused by the increased adsorption of the dye into fibers due to the local over heating and an amplified reaction probability between the dye and fiber. The physical properties of the acrylic fibers were elucidated using scanning electron microscopy (SEM), tensile strength measurements, and differential scanning calorimetry (DSC). The optimum time for the best dye uptake for given microwave powers was also reported.