At present, a higher demand is put towards the use of natural dyes due to increased awareness of the environmental and health hazards associated with the synthesis and use of synthetic dyes. This research was conducted using onion outer skins as a potential source of natural plant dyes. In this study, extraction of dye was carried out in aqueous boiling method. Premordanting technique was followed using different mordants, namely alum, ferrous sulphate, tin, tannic acid, tartaric acid, and their combinations on silk fabric. Fabric samples dyed without using any mordant were then compared with the dyed samples pretreated with the mordants. The range of colors developed on dyed materials was evaluated by measuring the color values with respect toK/Svalues and color coordinates. It was concluded that the color values were found to be influenced by the addition of mordants, and thus different fashion hues were obtained from the same amount of dye extract using different mordants. Ferrous sulphate was found as the most influential mordant.ΔEcmcvalues between unmordanted (Reference dyed) and metallic mordanted fabric samples were found higher than those between unmordanted and nonmetallic mordanted fabric samples. The dyed samples were evaluated for color fastness to washing, light, drycleaning, rubbing, and perspiration. The color fastness properties were found to be satisfactory and improved in many cases. From the fastness results, it was obvious that these dyes can also be applied on silk fabric without using any mordant if required.

Some common problems of textile dyeing industries include uneven or faulty dyeing and formation of color patches on the fabric surface during dyeing and downstream processing of textiles materials. Such problems in the finished quality of fabric are generally tackled through a chemical stripping process which is a common practice in dyeing industries for the deep shade batches. However, reactive dyes cannot be stripped satisfactorily from cellulosic materials due to the formation of co-valent bonds between dye and fiber. This research was undertaken using 2.5% and 5% bi-hetero reactive dyes on pretreated cotton fabric and dye stripping was carried out in alkali reductive stripping process. The aim of the work was to investigate the effects of dye stripping on the quality of cotton fabric. Strength loss, weight loss, pilling resistance and absorbency of stripped fabric were calculated. Though with the increase of concentration of stripping chemicals and temperature, stripping percentages were improved; processing damage to the fabric such as losses in strength, weight and pilling resistance ratings was found. In contrast, increased fabric absorbency was found due to stripping. This is explained that during stripping, alkaline solution as an intracrystalline swelling agent is effective in loosening the crystalline region of cotton in addition to the amorphous region. Stripping agent can also attack such crystalline region. As a result, cotton fiber can release maximum number of hydroxyl groups which previously formed covalent bonds. This is the reason behind the stripped fabric having more water absorbency.

The aim of the study was to evaluate the performance of dyes extracted from mango leaves in silk dyeing. Extraction medium was optimized by extracting dyes from fixed quantity of crushed leaves under pH values from 3 to 12. The maximum relative color strength of the extracted dye liquor was found to be at pH 10. The optimum dye extraction conditions i.e., the temperature, time, and material-to-liquor ratio were found to be 98°C, 60 min, and 1:10, respectively. Dyeing was carried out with the optimized dye extract on mordanted and unmordanted silk fabrics. The dyed materials were evaluated by measuring the color yield and fastness properties. It was concluded that the color values were found to be influenced by the addition of mordants, consequently different fashion hues were obtained from the same dye extract using different mordants. It can also be said that mango leaves have good potentiality for dyeing of silk fabric.

Silk nanofibers have been produced and examined in recent years for a range of advanced biomedical and biotechnological applications. Their fabrication involves the canonical approach of dissolving native silk fibers in a highly concentrated (mostly lithium-ion-based) chaotropic salt, followed by spinning fibers from the solution. Such methods of production involve the use of harmful chemicals and expensive and slow desalting steps. There is an alternative but less explored route to produce silk nanofibers: top-down processing to exfoliate nanofibers directly from native silk fibers. This approach takes advantage of the assembled bundles of silk nanofibers present in native silk fibers. Here, we report the use of this approach to produce silk nanofibers for the first time at a significant scale. We have demonstrated that tens of grams per batch of nano-microfibrillated silk (NMFS) can be produced without the use of chemicals; this is in sharp contrast to other reported methods that typically involve a microgram scale and/or chemically intensive top-down processing. We have adapted a combination of milling and the homogenization approach to prepare NMFS containing approximately 80% fibers with a diameter of less than 300 nm. Such fibers (1% w/v) produced a stable gel-like continuous network in water. The average aspect ratio was more than 50.

At present, customers are more conscious about the quality of clothing items. As a result, it becomes more challenging for the manufacturers to maintain the consistent dyeing quality. Unlevelness is generally unaccepted in commercial dyeing, except some cases such as stone-washed, acid-washed or pigment-dyed textiles. The aim of the study was to evaluate the color levelness quality of fabric dyed with vegetable dyes. For this purpose, dyeing was carried out on silk fabric with the aqueous extracts of mango, guava and henna leaves. Then the levelness of colored fabric was evaluated by spectrophotometric measurements in terms of color difference, ∆E value. It was concluded that unmordanted dyed samples have better color levelness quality than the mordanted ones. The unmordanted samples dyed with mango and guava leaves extracts showed excellent levelness quality while the unmordanted ones dyed with henna leaves extracts showed good levelness quality. On the other hand, the mordanted dyed samples showed good leveling quality for the three vegetable dyes except ferrous sulphate mordanted sample dyed with henna leaves extract. Again, among the mardanted samples the levelness quality was comparatively better in case of alum mordanted dyed samples and the average ∆E value was increased gradually when moved from alum to tin and finally to ferrous sulphate.