جستجوی مقالات مرتبط با کلیدواژه « natural dyes » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

The color sensitivity of the dyeing recipe is one of the most important parameters for controlling the dyeing process. This work studied the effect of color depth on the color sensitivity of a recipe of wool dyeing with weld natural dye. For this purpose, the woollen yarn was dyed with weld at low and high color depth using pre-mordanting method. The color sensitivity of the dyeing recipe was evaluated by measuring the color depth (K/S), color difference, and color sensitivity coefficient. The color sensitivity coefficient was measured by 10 % change in parameters of the dyeing recipe, such as dye concentration, mordant concentration, temperature, time, pH, and L.R. Also, the simultaneous color sensitivity of two, three, four, five, and six parameter combinations were measured by experimental and computational methods. The measured color sensitivity by the computational method was higher than the experimental method. In general, the color sensitivity at low color depth is more than high color depth.

The purpose of this study is to review and develop advanced strategies for using natural dyes in the art of handwoven carpet industry in the country. The current research is a descriptive-analytical type with an applied nature. The statistical population of this study includes 32 beneficiaries that have been purposefully identified and selected. Using the SOAR strategic model and Shannon's entropy method, information was collected via interviews and then analyzed, and strategies were developed to describe the organization's strengths, opportunities, ideals, and results. Based on the results from this research model, the strategies of using wastes, food waste, and agriculture industries as absorbents, and sources of natural dyes in handwoven carpet dyeing, strengthening and developing the cultivation of natural dyes, and optimal productivity in handwoven carpet production was introduced. The scores for benefiting techniques, new scientific methods in dyeing to enhance absorption and improve color stability are respectively 0.2209, 0.1652, and 0.1479. These effective strategies strengthen and develop natural dyes in the art of the handwoven carpet industry. 

Nowadays dyeing of textiles with natural dyes has been considered according to environmental effects based on lower using of the synthetic dyes and chemical auxiliaries. In present research, the dyeing parameters including; type of mordant, concentration of mordant and concentration of clove have been investigated. The color strength (K/S) value and the color coordinates (L*, a*, b*, C*) of samples were obtained using calorimeter in CIELab color space. The results showed the dyed samples in presence of Cu and Al as mordant have higher lightness (L*) compare with dyed samples dyed with Fe. The ultraviolet protection results showed higher blocking effect of sample in presence of clove against photodegradation of methylene blue (MB) under sunlight irradiation. The antibacterial assessment of the dyed samples showed reduction of bacteria rate against S. aureus (95%). Also washing fastness assessment of the dyed samples showed the great durability of clove on wool in presence of mordant.

Nowadays, despite the presence of synthetic dyes, due to the environmental damage caused by these substances, the approach of returning to natural sources has been revived. Meanwhile, the indigo plant is one of the best plant sources to achieve blue color. Much research has been conducted to extract dyes from indigo and woad since long ago. The purpose of this research is to collect the studies done in this field and, secondly, to use the results of previous research by researchers to improve the extraction methods. The results of the research showed that several methods, such as traditional, hot water, microbial, enzyme, microwave, etc., could be applied. It was also found that variables such as oxidation speed, oxidation time, alkaline environment of fermentation, type of alkaline material, resting time of fermentation, etc. influence the extraction process of indigo and woad dyes, the effect of pH is much important.</em>.</em>

Today, along with the increasing importance of environmental issues and the concept of social responsibility in societies, it seems necessary for consumers of different products to recognize the factors affecting the green mental image. Therefore, the importance of developing a new green product and its role in creating an organizational brand and positive imagery in the minds of customers is increasing and is one of the factors creating a competitive advantage for organizations. The main purpose of this study is to design and analyse a model to investigate the effect of two strategies of fibers and the use of natural dyes in the supply chain of raw materials in the development and visualization of green handmade carpet products by consumers, with structural equation modelling approach in Smart Pls software. In order to collect field information, a researcher-made questionnaire was used in the statistical population of handmade carpet consumers in Isfahan. The results showed that the development of the concept of green in the product and the intention to buy and consume them is an initiative and innovation that in addition to the prosperity of the green market, is an activity with high social value in human life. It was also found that the use of natural dyes in the dyeing of pile yarns has a stronger effect in creating and associating the concept of green product in handmade carpets than the raw material strategy.

Using natural dyes is one of the main features and advantages of eco-friendly Iranian hand-woven carpet, which has numerous adherents. This work studies the past, present, and future application of natural dyes for dyeing piles of the hand-woven carpet. Several investigations have been done on preparation, mordanting, and dyeing with natural dyes, as well as the use of a dyeing machine for dyeing the pile of hand-woven carpets. At the end of this research, little information is provided about the future of the use of natural dyes for dyeing piles of the hand-woven carpet. Studies show that if the extracted natural dyes produced  at high volume and reasonable prices, in the future, the hand-woven carpet piles can be dyed by fiber dyeing machine, yarn dyeing machine, hank dyeing machine, and bobbin yarn dyeing machine.

One of the main and essential problems in the dyeing units of the textile industry is the volume of pollutants produced, which has endangered the health of the environment through ground water pollution. Despite not causing respiratory and skin allergies and good compatibility with humans and nature, natural dyes can cause environmental problems by creating effluents. The resulting dyeing effluents often contain metal ions and colored compounds that can be harmful to the health of organisms and cause various diseases. Usually, different natural dyes such as madder, weld, walnut shell, and cochineal are used with different concentrations during the dyeing process. Besides, along with pre, simultaneous and post-mordanting methods, various mordants such as aluminum sulfate, copper sulfate, and potassium dichromate are applied. In this research, a review study has been conducted on the effect of using these dyes, types of applied mordant, and different dyeing methods on parameters such as BOD, COD, and TDS of resulted effluents.

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. Natural dyes are non-carcinogenic, produce soothing and exclusive color to the textiles, and have better biodegradability and higher compatibility with the environment. However, with the increased interest in natural plant dyes a greater importance was given to using mordant in dyeing processes. The mordants classified into two main groups: natural and metal mordant. The action of the mordant is purely chemical bonding, which is fixed on the fibers in combination with any given colorants. This paper presents the latest research on metal mordant and the development of natural mordant for use in the fiber dyeing process. For this end, an attempt structure properties to improve dyeing properties and to test landscape perspective.

In this study the natural colorants of Jasir, Madder and Pomegranate skin are considered to be compatible with wool yarns. To this end, the ability to dye each of the dyes of aluminum doped and dentinite sulfates was used as one of the most commonly used methods. The calculation results of this method showed that the dyeing curve of the three colors of dessert and reno are similar to each other. While the ability to dye wool yarn varies with dye of the skin of the pomegranate, it differs from that of the other two dyes. In this way, the similarity of the dyeing ability of the two gestures and the rhine reflects the relative adaptability of these colored materials. While the difference between the dyeing curve of pomegranate skin is low compatibility with jersey and rhinos. After calculating the ability to dye, dyeing of woolen yarn was done by combining two colors in three different dimensions. Then the degree of color matching was measured through common computational relationships. The computational results show that the colors of Madder and Jashir are in good harmony with each other. While the combination of pomegranate peel with any of the two dyes of Madder and Jashir results in low compatibility with weak to weak grades. In addition, the results of this study showed that the two concentrations of dye in the mixed bath and the use of the tooth affect the degree of compatibility and change the degree of color compatibility. Overall, the results of this study showed that the dye of Madder and Jashir are very consistent with each other and can be considered in the bathroom for the coloring of wool. While it is not possible to combine two colorful materials with pomegranate peel due to poor compatibility grade.

The raising of global warming and environmental pollution has increased the use of biodegradable polymers. On of the most important polymers in this kind are poly (lactic acid) (PLA), which has can be produced by the melting process which is the most efficient method for the fiber production. Poly (lactic acid) is a biodegradable alternative to poly (ethylene terephethalate) (PET) , in many technical textiles and clothing products. Although PLA is similar to PET in various aspects, PLA has different dyeing conditions from it. The results of researches show that PLA absorption isotherm with natural and synthetic dyes follow from nernst and langmuir isotherms. This paper reviews the recent developments in the dyeing of PLA fibers and textiles with disperse, vat, cationic and natural dyes.

Today, due to the concerns about the importance of environmental issues, the tendency of applying of natural dyes for dyeing the textile materials has been increased. In this regard, it is preferred to apply the natural additives instead of synthetic materials for pre-, meta- and post treatment processes. As instance, the use of herbal mordant instead of those of mineral or metal for dyeing process of natural fibers has been extremely attracted attentions. However, replacement of metal mordant by the herbal ones will influence both the colorimetric attributes as well as the color fastness of the final product. In this report, the basic concepts and studies related to definition of colorimetric attributes of natural dyes employed for cotton, woolen and silk textiles have been considered, firstly. Then, the effect of applying of natural dyes on different fastness properties, i.e., light fastness, wash fastness, wet and dry rubbing fastness have been reviewed.

Many types of colorants obtained from plants, animals and microbes sources have been investigated for their usage in different kinds of application. Much research into new natural colorants sources along with low cost and eco-friendly are in progress for their varied production and application in different domains. This paper present recent research performed in the area of application of natural colorants, with specific emphasis to technological development in natural textile and fabrics dyeing, food colorants and dye-sensitized solar cells. Finally, some newly discovered applications of natural colorants have been presented.

There is a demand for food colorants from natural sources that can serve as alternatives to the use of synthetic dyes. Anthocyanins demonstrate a high potential to be used as natural colorants due to their attractive orange, red and purple hues and water solubility that allows their incorporation into aqueous food systems. Different factors affect the color and stability of these compounds. For this reason many studies have been conducted with the aim of increasing the stability of these substances. There are several mechanisms applied in the process of anthocyanins stabilization whose main mechanisms are including: encapsulation and copigmentation. Encapsulation method has some drawbacks as the requirement for sophisticated equipments and high percentage of losses obtained in the process. Copigmentation can be a valuable, natural tool for improving the color of anthocyanin rich food products. Anthocyanin copigmentation gives brighter, stronger, and more stable colours than those of natural anthocyanin. This study provides an overview of copigmentation reaction types and the factors which affect its properties.